Method of monitoring peracid concentration by conductivity measurement, and peracid composition

Abstract

To provide a method of monitoring peracid concentration by conductivity measurement, and to provide a peracid composition.SOLUTION: Peroxycarboxylic acid compositions comprising compatible ionic compounds to deliver conductivity signals to enable monitoring of peroxycarboxylic acid concentration by conductivity when diluted for use are disclosed. Methods of measuring peroxycarboxylic acid concentration by conductivity are also disclosed. Beneficially, conductivity measurement allows a user to determine concentration of a peroxycarboxylic acid at a point of use without cumbersome titration steps to determine the concentration, providing various benefits in an application of use in cleaning, sanitizing or disinfection of a surface.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority under 35 U.S.C. § 119 to Provisional Application U.S. Ser. No. 62 / 855,209, filed May 31, 2019, which application claims priority under 35 U.S.C. § 119 to Provisional Application U.S. Ser. No. 62 / 855,209, filed May 31, 2019, the entire contents of which are incorporated herein by reference, including, without limitation, the specification, claims, and abstract, and any figures, tables, or examples thereof.

[0002] The present invention relates to peroxycarboxylic acid compositions containing ionic compounds compatible with the peroxycarboxylic acid composition to deliver a conductivity signal that allows for monitoring of peroxycarboxylic acid ("peracid") concentration by conductivity when diluted for use. A method for measuring peroxycarboxylic acid concentration by conductivity is also provided. Beneficially, conductivity measurement allows users to determine the concentration of peroxycarboxylic acid at the time of use without a tedious titration step to determine the concentration, providing various advantages in application. [Background technology]

[0003] Peroxycarboxylic acid compositions can be made by acid-catalyzed equilibrium reactions and are often generated in chemical plants and then shipped to customers for on-site use. Due to the inherent manufacturing, storage, transportation, and stability limitations of peroxycarboxylic acids, on-site generation of peroxycarboxylic acids is increasingly sought after. Regardless of the source of peroxycarboxylic acids, stability issues remain, presenting challenges for the accurate dosing and application of peroxycarboxylic acid concentrations. Depending on the specific peroxycarboxylic acid, half-lives can vary from minutes to hours to weeks to months.

[0004] Despite their inherent stability limitations, peroxycarboxylic acids are highly useful and effective in various technical fields such as cleaning, disinfection, sterilization, etc. Therefore, accurate dosing and delivery of peroxycarboxylic acids is necessary to reliably achieve the desired cleaning, disinfection, sterilization, or sterilization.

[0005] A conventional method for ensuring accurate dosing and delivery of cleaning compositions, such as peroxycarboxylic acids, is titration, a well-known and well-practiced method for determining the concentration of solution components. Titration of various chemicals is typically performed by adding a titrant to a solution, where the titrant reacts with the selected components. Once the entire reactant reacts with the known titrant, a measurable or noticeable change occurs, indicating that the reaction is complete. In some cases, the noticeable change includes a color change. For example, the color change can vary significantly between the various chemicals in the titration.

[0006] Titration can be a tedious process and requires careful practice by a chemist or other skilled operator. In some cases, data obtained by titration may be desirable, but having a chemist or other technician on hand to perform the titration may not be practical. Automated titrators can attempt to determine when complete reaction has occurred, and appropriate titration calculations can be performed to determine the amounts of components in solution. However, for some reactions, it may be difficult to accurately determine the reaction endpoint in an automated process. Furthermore, automated systems may require long periods of time to complete the process, which may be undesirable or unacceptable when solutions must be monitored at specific time intervals. While titration devices have advanced, this process is not favored in many areas where cleaning compositions, such as peroxycarboxylic acids, are dispensed. Instead, common practice is to simply over-dispense or deliver the cleaning composition, ensuring that the minimum required threshold is provided. However, this can result in unnecessary over-dispensing of chemicals and chemical waste, increasing costs.

[0007] Thus, there remains a need for methods for accurately determining the dosing and delivery concentration of peroxycarboxylic acids. Summary of the Invention [Problem to be solved by the invention]

[0008] It is therefore an object of the present disclosure to provide compositions that include ionic compounds that are compatible with peroxycarboxylic acids, such that conductivity measurements can determine the concentration of peroxycarboxylic acids.

[0009] It is a further object of the present disclosure to provide organic peroxycarboxylic acid compositions that can be measured by conductivity in a use solution.

[0010] Another object of the present disclosure is to formulate organic peroxycarboxylic acid compositions containing ionic compounds that are compatible with peroxycarboxylic acid, i.e., peroxyacetic acid, and that can be measured by conductivity in a use solution.

[0011] Other objects, aspects and advantages of the present invention will become apparent to those skilled in the art in view of the following disclosure, drawings and appended claims. [Means for solving the problem]

[0012] An advantage of the present invention is that it allows for monitoring of the peroxycarboxylic acid concentration by conductivity when diluted for use. Conductivity measurement allows the user to determine the concentration of peroxycarboxylic acid at the time of use without a tedious titration step to determine the concentration, providing various advantages in use.

[0013] In one embodiment, a method for monitoring peroxycarboxylic acid concentration includes providing a use solution of a peroxycarboxylic acid composition including an ionic compound, contacting a conductivity probe or sensor with the use solution, and detecting the conductivity signal to determine the peroxycarboxylic acid concentration in the use solution.

[0014] In a further embodiment, the peroxycarboxylic acid forming composition with conductivity monitoring capability includes a C1-C22 carboxylic acid, a hydrogen peroxide source, water, an ionic compound, and a stabilizer.

[0015] In a further embodiment, the peroxycarboxylic acid composition with conductivity monitoring capability comprises about 5-20 wt. % peroxyacetic acid, about 15-40 wt. % acetic acid, about 5-50 wt. % hydrogen peroxide, water, about 5-50 wt. % ionic compound, and about 0.001-5 wt. % stabilizer.

[0016] While multiple embodiments are disclosed, still other embodiments will become apparent to those skilled in the art from the following detailed description, which shows and describes illustrative embodiments. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not restrictive. [Brief explanation of the drawings]

[0017] [Figure 1] 1 shows graphical measurements of peroxyacetic acid concentration and conductivity measurements using Formulation 1 of the evaluated peroxycarboxylic acid compositions disclosed in the Examples. [Figure 2] 1 shows graphical measurements of peroxyacetic acid concentration and conductivity measurements using Formulation 2 of the evaluated peroxycarboxylic acid composition disclosed in the Examples. [Figure 3] 1 shows a graphical measurement of the effect of ionic compounds in evaluated peroxycarboxylic acid compositions disclosed in the Examples on antimicrobial efficacy against Staphylococcus aureus and Escherichia coli in use solutions. [Figure 4] 1 shows a graphical measurement of the effect of ionic compounds in evaluated peroxycarboxylic acid compositions disclosed in the Examples on antimicrobial efficacy against Pseudomonas aeruginosa in use solutions. [Figure 5] 1 is a graph of calcium phosphate solubility in peroxyacetic acid formulations showing dissolved calcium in solutions of Oxonia Active (0.20%, 0.24%, and 0.28% v / v) and Formulation 2 (0.11%, 0.15%, and 0.20% v / v) with calcium phosphate addition (300 RPM, 5 minutes, 25° C.). [Figure 6]1 is a graph of calcium carbonate solubility in peroxyacetic acid formulations showing dissolved calcium in solutions of Oxonia Active (0.20%, 0.24%, and 0.28% v / v) and Formulation 2 (0.11%, 0.15%, and 0.20% v / v) with calcium carbonate addition (300 RPM, 5 minutes, 25° C.). [Figure 7] 1 shows a graph of a SADT study of peroxycarboxylic acid compositions containing ionic compounds for conductivity monitoring.

[0018] Various embodiments of the present invention will now be described in detail with reference to the drawings, wherein like reference numerals represent like parts throughout the several views. Reference to various embodiments does not limit the scope of the invention. The figures presented herein are presented for illustrative purposes only and are not intended to limit the various embodiments according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0019] Embodiments are not limited to the particular peroxycarboxylic acid composition containing an ionic compound and / or the method of measuring the peroxycarboxylic acid composition concentration using a conductivity method, which may vary and will be understood by those skilled in the art. Surprisingly, peroxycarboxylic acid compositions can be accurately measured by conductivity, allowing users of the compositions to quickly determine the concentration for administering the composition, which provides various advantages and uses not previously available for peroxycarboxylic acid compositions.

[0020] It should be further understood that all terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting in any manner or scope. For example, as used in this specification and the appended claims, the singular forms "a," "an," and "the" may include plural referents unless the content clearly dictates otherwise. Furthermore, all units, prefixes, and symbols may be denoted in their SI-accepted form. Numerical ranges recited within this specification include numbers within the defined range. Throughout this disclosure, various aspects are presented in range format. It should be understood that the description in range format is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the invention. Thus, the description of a range should be considered to specifically disclose each and every numerical value within that range (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5) along with all possible subranges.

[0021] In order to make the present invention more readily understandable, certain terms are first defined. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the embodiments of the present invention pertain. Many methods and materials similar, modified, or equivalent to those described herein can be used to practice the embodiments of the present invention without undue experimentation, and preferred materials and methods are described herein. In describing and claiming the embodiments, the following terminology will be used in accordance with the definitions set forth below.

[0022] As used herein, the term "about" refers to variations in numerical quantities that may occur, for example, due to typical measuring and liquid handling procedures used to make concentrates or use solutions in the real world, due to inadvertent errors in these procedures, and due to differences in the manufacture, source, or purity of ingredients used to make a composition or practice a method. The term "about" also encompasses amounts that differ due to different equilibrium conditions for a composition resulting from a particular initial mixture. Whether modified by the term "about," the claims include equivalents to the amount.

[0023] The terms "actives" or "percent actives" or "percent actives by weight" or "actives concentration" are used interchangeably herein and refer to the concentration of ingredients involved in cleaning expressed as a percentage minus inactive ingredients such as water or salt.

[0024] As used herein, the term "free" refers to a composition that is completely devoid of the component or that has such a small amount of the component that it does not affect the performance of the composition. The component may be present as an impurity or contaminant and must be less than 0.5% by weight. In another embodiment, the amount of the component is less than 0.1% by weight, and in yet another embodiment, the amount of the component is less than 0.01% by weight.

[0025] As used herein, the terms "mixed" or "mixture," when used in reference to a "peroxycarboxylic acid" or "peroxycarboxylic acid composition," refer to a composition or mixture that includes two or more peroxycarboxylic acids.

[0026] The terms "weight percent," "wt%," "percent by weight," "% by weight," and variations thereof, as used herein, refer to the concentration of a substance as the weight of that substance divided by the total weight of the composition multiplied by 100. As used herein, it is understood that "percent," "%," and the like are intended to be synonymous with "weight percent," "wt%," and the like.

[0027] The methods and compositions may comprise, consist essentially of, or consist of the components and ingredients described herein, as well as other ingredients. As used herein, "consisting essentially of" means that the methods and compositions may include additional steps, components, or ingredients so long as the additional steps, components, or ingredients do not materially alter the basic and novel characteristics of the claimed methods and compositions.

[0028] Peroxycarboxylic Acid Composition According to embodiments, the peroxycarboxylic acid composition includes peroxycarboxylic acid, carboxylic acid, oxidizing agent, water, ionic compound, and optional additional ingredients such as stabilizers. The composition can include additional functional ingredients and can be provided as a concentrate or a use composition. Exemplary peroxycarboxylic acid-forming compositions, by weight percent, are shown in Tables 1A and 1B, and peroxyacetic acid-forming compositions are shown in Table 2. [Table 1] [Table 2] [Table 3]

[0029] In weight percent, exemplary peroxycarboxylic acid compositions are shown in Tables 3A and 3B, and peroxyacetic acid compositions are shown in Table 4. The peroxycarboxylic acid compositions are balanced compositions. [Table 4] [Table 5] [Table 6]

[0030] In various aspects of the embodiments, including those set forth in Tables 1-4, the peroxycarboxylic acid composition meets the requirements for organic certification by the National Organic Program. In some embodiments, the ionic compound and oxidizing agent, together with the peroxycarboxylic acid composition, meet the requirements for organic certification.

[0031] Peroxycarboxylic Acid Composition Peroxycarboxylic (or percarboxylic) acids generally have the formula R(COH) n where, for example, R is an alkyl, arylalkyl, cycloalkyl, aromatic, or heterocyclic group, and n is 1, 2, or 3, and is referred to by the prefix "peroxy" after the parent acid. The R group can be saturated or unsaturated, and substituted or unsubstituted. The composition can include a mixture or combination of several different peroxycarboxylic acids. Such compositions are often referred to as mixed peroxycarboxylic acids or mixed peroxycarboxylic acid compositions. For example, in some embodiments, the composition can include one or more C1-C4 peroxycarboxylic acids and one or more C5-C6 peroxycarboxylic acids. 12 Contains peroxycarboxylic acid.

[0032] As referred to herein, the methods and compositions of use can include either peroxycarboxylic acids (or peroxycarboxylic acid compositions including peroxycarboxylic acids, carboxylic acids, hydrogen peroxide, water, and any additional components), or mixed peroxycarboxylic acids (or peroxycarboxylic acid compositions including two or more peroxycarboxylic acids, two or more carboxylic acids, hydrogen peroxide, water, and any additional components).

[0033] Peroxycarboxylic acid compositions can be formed by combining one or more carboxylic acids with an oxidizing agent (e.g., hydrogen peroxide). Peroxycarboxylic acid compositions, monitored by conductivity, have a pH of about 2-9 in use solutions, or about 2-5, or less than about 5, when diluted from various types of water. In a preferred embodiment, the peroxycarboxylic acid composition is constituted as peroxyacetic acid.

[0034] Carboxylic Acid The peroxycarboxylic acid composition is formed by combining at least one carboxylic acid with an oxidizing agent. In some embodiments, at least two, at least three, or at least four or more carboxylic acids can be used. Carboxylic acids for use with the compositions of the present invention include C1-C 22 In some embodiments, the carboxylic acid for use with the compositions of the present invention is a C5-C 11 Carboxylic acids. In some embodiments, the carboxylic acid is a C1-C5 carboxylic acid. Examples of suitable carboxylic acids include, but are not limited to, formic acid, acetic acid, propionic acid, butanoic acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, dodecanoic acid, and branched isomers thereof, lactic acid, maleic acid, ascorbic acid, citric acid, hydroxyacetic acid, neopentanoic acid, neoheptanoic acid, neodecanoic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, and mixtures thereof.

[0035] Preferred carboxylic acids include those that are organic compounds and / or have organic certification, such as acetic acid to produce peroxyacetic acid.

[0036] In some embodiments, the carboxylic acid is included in the peroxycarboxylic acid-forming composition in an amount of at least about 5% to about 50%, about 15% to about 50%, about 15% to about 40%, or about 15% to about 30% by weight. Further, without limitation in accordance with the present invention, all recited ranges are inclusive of the numbers defining the range and include each integer within the defined range.

[0037] oxidizing agent Peroxycarboxylic acid compositions are formed by combining at least one carboxylic acid with an oxidizing agent. Examples of inorganic oxidizing agents include the following types of compounds or sources of these compounds, or alkali metal salts that contain or form adducts with these types of compounds: hydrogen peroxide or the following hydrogen peroxide donors: Group 1 (IA) oxidizers, such as lithium peroxide, sodium peroxide; Group 2 (IIA) oxidizers, such as magnesium peroxide, calcium peroxide, strontium peroxide, barium peroxide; Group 12 (IIB) oxidizers, such as zinc peroxide; Group 13 (IIIA) oxidizers, such as boron compounds such as perborates, e.g., sodium perborate hexahydrate of the formula Na[BiOMOH)].6H0 (also called sodium perborate tetrahydrate); NaBiO[(OH)].4H0 (perborate sodium peroxyborate tetrahydrate, of the formula Na[BiO)iOH] (also called sodium perborate monohydrate); Group 14 (IVA) oxidizers, such as persilicates and peroxycarbonates, also called percarbonates, such as persilicates or peroxycarbonates of alkali metals; Group 15 (VA) oxidizers, such as peroxynitrite and its salts; peroxyphosphoric acid and its salts, such as superphosphoric acid; Group 16 (VIA) oxidizers, such as peroxysulfuric acid and its salts, such as peroxymonosulfuric acid and peroxydisulfuric acid, and their salts, such as persulfates, e.g., sodium persulfate; and Group VIIa oxidizers, such as sodium periodate, potassium perchlorate, etc. Other active inorganic oxygen compounds may include transition metal peroxides and other such peroxygen compounds, and mixtures thereof.

[0038] In some embodiments, the compositions and methods of the present invention use one or more of the inorganic oxidizing agents listed above. Suitable inorganic oxidizing agents include ozone, hydrogen peroxide, hydrogen peroxide adducts, Group IIIA oxidizing agents, or hydrogen peroxide 30 donors of Group VIA oxidizing agents, Group VA oxidizing agents, Group VIIA oxidizing agents, or mixtures thereof. Suitable examples of such inorganic oxidizing agents include percarbonates, perborates, persulfates, perphosphates, persilicates, or mixtures thereof.

[0039] Hydrogen peroxide is one suitable example of an inorganic oxidizing agent. Hydrogen peroxide can be provided as a mixture of hydrogen peroxide and water, for example, as liquid hydrogen peroxide in an aqueous solution. Hydrogen peroxide is commercially available in concentrations of 35%, 40-70%, and 90% in water. For safety reasons, 35-50% is commonly used.

[0040] Preferred oxidizing agents include those that are organic compounds and / or have organic certification, such as hydrogen peroxide.

[0041] In some embodiments, the oxidizing agent is included in the peroxycarboxylic acid-forming composition in an amount of at least about 10% to about 70%, about 15% to about 70%, about 20% to about 70%, or about 25% to about 65% by weight. Further, without limitation in accordance with the present invention, all recited ranges are inclusive of the numbers defining the range and include each integer within the defined range.

[0042] water In some embodiments, the peroxycarboxylic acid-forming composition can include water. Water can be added separately to the composition or can be provided in the composition as a result of its presence in an aqueous material added to the composition. In some embodiments, the composition contains about 0% to about 30% by weight water, about 0.1% to about 30% by weight water, about 0.1% to about 20% by weight water, or about 0.5% to about 15% by weight water. It is understood that all values and ranges between these values and ranges are encompassed by the methods of the present invention.

[0043] ionic compounds The peroxycarboxylic acid composition contains at least one ionic compound for delivering a conductivity signal that allows for monitoring of the peroxycarboxylic acid concentration by conductivity when diluted for use. The ionic compound must be compatible with the peroxycarboxylic acid without reducing its stability and / or antimicrobial effectiveness. Suitable ionic compounds include, but are not limited to, alkaline earth metal salts, such as alkali metal salts, magnesium salts, and hydronium salts.

[0044] Preferably, the ionic compound is a magnesium salt. Exemplary magnesium salts include, but are not limited to, magnesium acetate, magnesium benzoate, magnesium citrate, magnesium formate, magnesium hexafluorosilicate, magnesium hydroxide, magnesium lactate, magnesium molybdate, magnesium nitrate, magnesium perchlorate, magnesium phosphonate, magnesium salicylate, magnesium sulfate, magnesium sulfite, hydrates thereof, and mixtures thereof.

[0045] Preferred magnesium salts include magnesium sulfate, magnesium acetate, and magnesium nitrate. More preferred magnesium salts include those that are GRAS approved for direct food contact, such as organic compounds and / or magnesium sulfate.

[0046] Exemplary aluminum salts include, but are not limited to, aluminum acetate, aluminum benzoate, aluminum citrate, aluminum formate, aluminum hexafluorosilicate, aluminum lactate, aluminum molybdate, aluminum nitrate, aluminum perchlorate, aluminum phosphonate, aluminum salicylate, aluminum sulfate, hydrates thereof, and mixtures thereof.

[0047] Hydronium salts have the general formula HO +A- is a salt of an acid having the formula (A). Exemplary hydronium salts include, but are not limited to, hydronium sulfate, hydrogen sulfate, nitrate, phosphate, phosphonate, sulfonate, acetate, formate, citrate, lactate, and gluconate. Preferably, hydronium sulfate, i.e., sulfuric acid, H2SO4, is used in the peroxycarboxylic acid composition to provide conductivity because it is highly efficient at delivering conductivity.

[0048] As an added benefit, the use of hydronium salts, e.g., sulfuric acid, provides additional benefits for scale removal and biofilms. While not limited to a particular mechanism of action, sulfuric acid provides a low pH that not only prevents and removes mineral scale, but also beneficially provides effective biofilm destruction and removal. In one embodiment, biofilm efficacy is achieved at a pH of about 3 or less, or preferably about 2.3 or less. Thus, in preferred embodiments, compositions containing hydronium salt ionic species (particularly sulfuric acid, in some embodiments) at levels of at least about 5% by weight provide effective performance against biofilms and provide stabilized peroxycarboxylic acid compositions with traceable conductivity.

[0049] In some embodiments, the ionic compound is included in the peroxycarboxylic acid composition in an amount of at least about 5% to about 50%, about 10% to about 50%, about 10% to about 40%, or about 15% to about 40% by weight. Further, without limitation in accordance with the present invention, all recited ranges are inclusive of the numbers defining the range and include each integer within the defined range.

[0050] In one embodiment, the ratio of ionic compound to peroxycarboxylic acid in the composition is about 5:1 to 1:5 to ensure a reliable conductivity signal. In other embodiments, increasing the ratio of ionic compound to peroxycarboxylic acid may provide additional conductivity signal benefits. In some embodiments, the ratio of ionic compound to peroxycarboxylic acid in the composition is greater than 5:1, e.g., 6:1, 7:1, 8:1, 9:1, 10:1, or greater. Without being limited to a particular mechanism of action, a concentration of at least about 5% by weight of ionic compound provides a sufficient concentration to ensure a reliable conductivity signal. This differs from the use of hydronium salts, e.g., sulfuric acid, or mineral acid catalysts in peroxycarboxylic acid compositions to catalyze or accelerate the reaction to form an equilibrium peroxycarboxylic acid composition, because such concentrations are in lower amounts, e.g., less than about 1% by weight, or less than about 2% by weight. However, such conventional use of mineral acid catalysts does not provide the composition with water conductivity.

[0051] Additional Functional Ingredients The components of the peroxycarboxylic acid composition can be combined with various functional components suitable for use as disclosed herein. In some embodiments, the peroxycarboxylic acid composition, including peroxycarboxylic acid, carboxylic acid, hydrogen peroxide, ionic compound, and water, constitutes a majority or substantially all of the total weight of the composition. For example, in some embodiments, little or no additional functional components are disposed therein.

[0052] In other embodiments, additional functional ingredients may be included in the composition. The functional ingredient imparts desired properties and functionality to the composition. For purposes of this application, the term "functional ingredient" includes materials that, when dispersed or dissolved in a use solution, such as an aqueous solution, and / or a concentrated solution, provide beneficial properties in a particular use. Some specific examples of functional materials are described in more detail below, although the specific materials described are provided merely as examples, and a wide variety of other functional ingredients may be used. For example, many of the functional materials described below relate to materials used in cleaning. However, other embodiments may include functional ingredients for use in other applications.

[0053] In some embodiments, the peroxycarboxylic acid composition may include stabilizers. In other embodiments, the peroxycarboxylic acid composition may include optical brighteners, defoamers, anti-redeposition agents, bleaching agents, solubility modifiers, dispersants, metal protectants, soil anti-redeposition agents, stabilizers, corrosion inhibitors, builders / sequestering / chelating agents, enzymes, aesthetic enhancers including fragrances and / or dyes, additional rheology and / or solubility modifiers or thickeners, hydrotropes or couplers, buffers, solvents, additional cleaning agents, etc. These additional ingredients may be preformulated with the composition or added to the use solution before, after, or substantially simultaneously with the addition of the composition.

[0054] According to embodiments of the present invention, various additional functional ingredients may be provided in the composition in amounts of about 0% to about 50% by weight, about 0.01% to about 50% by weight, about 0.1% to about 50% by weight, about 1% to about 50% by weight, about 1% to about 30% by weight, about 1% to about 25% by weight, or about 1% to about 20% by weight. Further, without being limited according to the present invention, all ranges recited are inclusive of the numbers defining the range and include each integer within the defined range.

[0055] stabilizers The peroxycarboxylic acid composition may include a stabilizer. The stabilizer prevents or slows the decomposition of the peracid in the equilibrium peroxycarboxylic acid composition. According to embodiments of the present invention, various stabilizers may be provided in the composition in amounts of about 0% to about 20% by weight, about 0.1% to about 20% by weight, about 1% to about 20% by weight, about 1% to about 10% by weight, or about 1% to about 5% by weight. According to preferred embodiments, various stabilizers may be provided in the composition in amounts of about 0% to about 5% by weight, about 0.001% to about 5% by weight, about 0.01% to about 1% by weight, or about 0.05% to about 0.5% by weight. Furthermore, without limitation according to the present invention, all recited ranges are inclusive of the numbers defining the range and include each integer within the defined range.

[0056] Suitable stabilizers for use in peroxycarboxylic acid compositions include, for example, pyridine carboxylic acid compounds. Pyridine carboxylic acids include, for example, dipicolinic acid, including 2,6-pyridinedicarboxylic acid (DPA). In a further embodiment, the stabilizer is picolinic acid or a salt thereof. In one embodiment of the present invention, the stabilizer is picolinic acid or a compound represented by the following formula (IA): [ka] (Wherein, R1 is OH or -NR 1a R 1b and R 1a and R 1b are independently hydrogen or (C1-C6) alkyl, and R 2 -OH or -NR 2a R 2b and R 2a and R 2b are independently hydrogen or (C1 to C 6) alkyl, and each R 3 are independently (C1-C6) alkyl, (C2-C6) alkenyl, or (C2-C6) alkynyl, and n is a number from 0 to 3, or a salt thereof.

[0057] In a further aspect of the invention, the peracid stabilizer has the following formula (IB): [ka] (In the formula, R 1 -OH or -NR 1a R 1b and R 1a and R 1b are independently hydrogen or (C1-C6) alkyl, and R 2 -OH or -NR 2a R 2b and R 2a and R 2b are independently hydrogen or (C1 to C 6) alkyl, and each R 3 are independently (C1-C6) alkyl, (C2-C6) alkenyl, or (C2-C6) alkynyl, and n is a number from 0 to 3, or a salt thereof. Preferred stabilizers include organic compounds such as dipicolinic acid.

[0058] Additional stabilizers suitable for use in the peroxycarboxylic acid composition include, for example, phosphonic acid or phosphonate salts and aminocarboxylic acids (aminocarboxylic acid-type sequestering agents). Suitable phosphonic acid and phosphonate salts include, for example, 1-hydroxyethylidene-1,1-diphosphonic acid (CHC(POH)OH) (HEDP), ethylenediaminetetrakismethylenephosphonic acid (EDTMP), diethylenetriaminepentakismethylenephosphonic acid (DTPMP), cyclohexane-1,2-tetramethylenephosphonic acid, amino[tri(methylenephosphonic acid)], (ethylenediamine[tetramethylene-phosphonic acid)], 2-phosphenebutane-1,2,4-tricarboxylic acid, or salts thereof, such as alkali metal salts, ammonium salts, or alkyloylamine salts, such as mono-, di-, or tetra-ethanolamine salts, or mixtures thereof. In some embodiments, the chelating agent comprises 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP). Preferred stabilizers include organic compounds such as HEDP.

[0059] Suitable aminocarboxylic acid type sequestering agent or stabilizer includes, but is not limited to, acid or its alkali metal salt, for example, aminoacetic acid and its salt.Suitable aminocarboxylic acid salts include, for example, N-hydroxyethylaminodiacetic acid, methylglycine diacetic acid (MGDA), hydroxyethylenediaminetetraacetic acid, nitrilotriacetic acid (NTA), ethylenediaminetetraacetic acid (EDTA), N-hydroxyethyl-ethylenediaminetriacetic acid (HEDTA), glutamic acid N,N-diacetic acid (GLDA), diethylenetriaminepentaacetic acid (DTPA), iminodisuccinic acid (IDS), ethylenediaminedisuccinic acid (EDDS), 3-hydroxy-2,2-iminodisuccinic acid (HIDS), hydroxyethyliminodiacetic acid (HEIDA), and alanine-N,N-diacetic acid, and mixtures thereof.

[0060] In a preferred embodiment, at least two stabilizers are included in the composition, such as dipicolinic acid and HEDP.

[0061] In some embodiments, the stabilizer is phosphorus-free and the peroxycarboxylic acid composition is phosphorus-free.

[0062] In some embodiments, the weight ratio of ionic compound to stabilizer in the composition is from about 8:1 to about 15:1, or from about 8:1 to about 13:1. Compared to the conventional use of some ionic compounds (e.g., metal salts) for stabilization of peroxycarboxylic acid compositions, significantly higher concentrations of ionic compound are required to deliver a conductivity signal, which uses a molar ratio of metal salt to chelating agent or stabilizer of from about 5:1 to about 1:14.

[0063] How to use Peroxycarboxylic acid compositions have many uses. They are suitable for cleaning and disinfecting compositions, such as those suitable for cleaning hard surfaces and objects and removing dirt, scale, and / or biofilm from such surfaces and objects, including clean-in-place (CIP) and clean-out-of-place (COP) applications. They are also suitable for disinfecting water sources, treating membranes, laundry applications, sterilizing instruments and / or devices, and the like. For various uses of peroxycarboxylic acid, it is desirable for users to easily identify the concentration of peroxycarboxylic acid to be administered and / or dispensed for a particular use. This not only provides a sufficient concentration for the intended cleaning (including removal of dirt, scale, and / or biofilm), disinfecting, and / or sterilizing effect, but also reduces overuse or consumption of the peroxycarboxylic acid composition. In a preferred embodiment, the peroxycarboxylic acid composition is a disposable composition.

[0064] In addition to the advantages described herein, conductivity measurements allow the user to determine the concentration of peroxycarboxylic acid at the time of use without a tedious titration step to determine the concentration, providing various advantages in use.

[0065] Advantageously, according to some embodiments, the peroxycarboxylic acid-containing use solution is provided in a stabilized, phosphorus-free composition. In yet another embodiment, the peroxycarboxylic acid-containing use solution is an organic peroxycarboxylic acid composition. In a further embodiment, the use solution is further a stabilized, phosphorus-free, organic peroxycarboxylic acid composition.

[0066] In some embodiments, compositions containing hydronium salt ionic species (e.g., sulfuric acid) at levels of at least about 5% by weight provide effective performance against biofilms and provide stabilized peroxycarboxylic acid compositions capable of tracking conductivity. Embodiments using hydronium salts, such as sulfuric acid, provide advantages for descaling and / or biofilm removal at acidic pHs in the use solution, i.e., pHs below about 3 or below about 2.3. Without being limited to a particular mechanism of action, sulfuric acid provides a low pH that not only prevents and removes mineral scale, but also beneficially provides effective biofilm destruction and removal. Further embodiments in which the compositions contain hydronium salt ionic species (e.g., sulfuric acid) provide advantages in effectiveness against non-biofilm bacteria, such as Listeria spp., including Listeria monocytogenes, in addition to biofilms.

[0067] The methods disclosed herein are suitable for use in monitoring and / or detecting the concentration of peroxycarboxylic acid compositions circulated within a system and / or cleaning application (e.g., before and / or during an application). In a further aspect, the methods are suitable for use in monitoring and / or detecting the concentration of peroxycarboxylic acid compositions stored and / or contained prior to an application.

[0068] The disclosed method is suitable for testing use solutions, which are particularly useful to users of the composition at the point of use, because the use solution (rather than the concentrate) is applied to a surface. Use solutions can be prepared from concentrates by diluting the concentrate with water at a dilution ratio that provides a use solution with the desired disinfecting and / or other antimicrobial properties. The water used to dilute the concentrate to form the use composition may be referred to as dilution water or diluent and may vary depending on location. Typical dilution factors are approximately 1 to approximately 10,000, but will depend on factors including water hardness, the amount of soil, scale, and / or biofilm to be removed, and the like. In one embodiment, the concentrate is diluted at a ratio of about 1:10 to about 1:10,000. Specifically, the concentrate is diluted at a ratio of about 1:100 to about 1:5,000. More specifically, the concentrate is diluted at a ratio of about 1:250 to about 1:2,000.

[0069] The frequency with which the peroxycarboxylic acid concentration of the use solution is monitored (e.g., monitoring frequency) will vary depending on the desired use application. For example, the monitoring device may be programmed to monitor the concentration of peroxycarboxylic acid in the use composition initially prior to the time of delivery. Alternatively, the concentration may be monitored every 15 minutes, every 30 minutes, every hour, every 2 hours, daily, or other suitable time. The monitoring frequency / interval may vary depending, among other things, on the particular application for which the use composition is intended and the corresponding threshold concentration of peroxycarboxylic acid.

[0070] Detection sensitivities using ionic compounds can range from a few ppm to over 10,000 ppm, which advantageously allows for detection of peroxycarboxylic acid concentrations for delivery to a variety of applications requiring 1 ppm or greater.

[0071] The detection method can be carried out at any suitable temperature. In some embodiments, the method of the present invention is carried out at a temperature ranging from about 0°C to about 70°C, e.g., from about 0°C to about 4°C or 5°C, from about 5°C to about 10°C, from about 11°C to about 20°C, from about 21°C to about 30°C, from about 31°C to about 40°C, including about 37°C, from about 41°C to about 50°C, from about 51°C to about 60°C, or from about 61°C to about 70°C.

[0072] The method for measuring peroxycarboxylic acid concentration using conductivity includes contacting a peroxycarboxylic acid composition with a conductivity sensor or probe. The methods described herein are not limited by the specific sensor, probe, and / or cell used to measure the conductivity of the acidic peroxycarboxylic acid composition, as long as the sensor, probe, and / or cell is compatible with the acidic peroxycarboxylic acid composition. Conductivity is measured in units of mS / cm (equivalent to expressing conductivity measurements as μS / cm).

[0073] Conductivity probes provide an electroanalytical method for measuring product parameters. An exemplary conductivity sensor includes two electrodes and operates by applying a voltage between the two electrodes and measuring the resulting current. The relationship between the magnitude of the current and the voltage allows the resistance, and therefore the conductivity, of the product to be determined.

[0074] The use of sensors (which may also be referred to as optical cells and / or optical detectors) also provides electroanalytical methods for measuring product parameters. Exemplary sensors are disclosed in methods and / or apparatus in, for example, U.S. Patent Publication No. 2012 / 0014912, and U.S. Patent Nos. 8,835,874, 8,229,204, 8,143,070, 8,119,412, 8,187,540, 8,084,756, 8,076,155, 8,076,154, 7,572,687, and 7,169,236, which are incorporated by reference.

[0075] In one embodiment, the method includes providing a sensor, probe, and / or cell in a position that contacts the peroxycarboxylic acid composition to measure a sample of the use solution. Without being limited to the specific sequence of events of the method described herein, conductivity can be measured at various points in the sequence of events generally described herein. In one embodiment, conductivity is measured in a stream or volume of peroxycarboxylic acid composition prior to administration. In a further embodiment, conductivity is preferably measured at the outlet and / or reservoir of a generator for the peroxycarboxylic acid composition. For example, in various applications, an on-site generator for peroxycarboxylic acid composition can be used, and the concentration of the peroxycarboxylic acid composition can be measured at the inlet, piping, outlet, and / or reservoir (e.g., storage) of the generated peroxycarboxylic acid composition. In a further embodiment, conductivity is measured in a stream or vessel that delivers the peroxycarboxylic acid composition in a use application.

[0076] In one embodiment, the concentration of the peroxycarboxylic acid composition can be measured by first measuring the conductivity of water as a baseline or control, and the difference between the conductivity measurement of the peroxycarboxylic acid use solution and the water control is used to measure the concentration of peracid.

[0077] In one embodiment, measuring the conductivity of a peroxycarboxylic acid composition is used to determine whether the concentration of peroxycarboxylic acid meets at least a minimum threshold concentration for a desired application (e.g., stain, scale, and / or biofilm removal, or other application). For example, application-specific concentrations may include aseptic bottle rinse, which typically requires about 1000-5000 ppm peracid, or central disinfection, which typically requires about 100-1000 ppm peracid.

[0078] In one embodiment, suitable carriers or solvents for forming the use solution of the peroxycarboxylic acid composition include various types of water. In one embodiment, deionized water, soft water, and / or hard water (e.g., 5 grains or greater) can all be used to measure conductivity. Advantageously, conductivity measurements can be achieved without being limited to a particular type of water.

[0079] Thereafter, a method for measuring peroxycarboxylic acid concentration using conductivity may include applying or contacting the composition to equipment, surfaces, substrates, etc., that require cleaning, disinfecting, sanitizing, etc.

[0080] Conductivity measurements can be combined with a variety of other measurements and measurement devices that may be desired for peroxycarboxylic acid compositions, i.e., peroxycarboxylic acid compositions generated on-site. One or more measurement devices can be combined with the device to measure conductivity. Exemplary measurement devices are those suitable for measuring one or more reaction kinetics or system operations for the generation of peroxycarboxylic acid compositions, including, for example, devices for measuring weight, flow rate (e.g., flow meters or switches), pH, pressure, temperature, and combinations thereof. Examples of additional suitable measurement devices include, for example, thermometers, out-of-product alarms, peroxide monitors, IR / UV / VIS spectroscopy, NMR, and pressure switches.

[0081] Conductivity measurements using a conductivity sensor can be combined with various control systems. In some embodiments, it may be desirable to couple the conductivity measurement functionality with any controller or software platform. The software platform can provide a user or system with the ability to select a desired peroxycarboxylic acid formulation for on-site production based on the conductivity measurement. For example, the controller or control software for operating the system may enable the user or system to select additional peroxycarboxylic acid formulations, as well as the desired volume and dosage concentration of the formulation for on-site production, based on the conductivity measurement. In further embodiments, the control software can determine the timing, sequencing, and / or selection of raw material (e.g., reagent) supply to the system, the mixing time, and total reaction time required to produce the user- or system-selected peroxycarboxylic acid formulation. Various other aspects of the control system, including, for example, options for display by the control software platform (e.g., display screens for the user interface), are known to those skilled in the art. Examples of suitable controllers are disclosed herein and further in various embodiments of those disclosed in U.S. Pat. Nos. 7,547,421 and 8,075,857, both entitled "Apparatus and Method for Making Peroxycarboxylic Acid," which are incorporated herein by reference in their entireties.

[0082] The conductivity measurement can be combined with or include a data output means. The data output means is useful for sharing information related to the peroxycarboxylic acid composition measured by conductivity and / or the peroxycarboxylic acid composition produced on-site and also measured by conductivity. For example, the information backbone can be used to collect and disseminate data from the process of producing the peroxycarboxylic acid composition, including, for example, consumption, distribution, or use of the composition, and additional formulation production-related data. Such data can be generated in real time and / or provided in a historical log of operational data that can be detected or stored by a user or system. These and other embodiments of data output means, information sharing, remote system operation, and the like that can be adapted for use in the methods described herein are further described in, for example, U.S. Pat. Nos. 8,162,175, 7,292,917, 6,895,307, 6,697,706, and 6,377,868, and U.S. Patent Publication Nos. 2005 / 0065644, 2004 / 0088076, and 2003 / 0195656, which are expressly incorporated herein by reference.

[0083] In embodiments employing a control system and / or data output means, a user or system can monitor usage and operation, including, for example, dispensing chemicals, managing chemical distribution to various use locations, communicating with a system operator to control and monitor chemical distribution, allocation, and / or blending, etc. According to additional embodiments, a user or system can remotely control the system, including programming the system and managing the data output. [Example]

[0084] Embodiments of the present invention are further defined in the following non-limiting examples. It should be understood that these examples, while illustrating specific embodiments of the present invention, are given by way of illustration only. From the above description and these examples, one skilled in the art can ascertain the essential features of the present invention and can make various changes and modifications to the embodiments of the present invention to adapt them to various uses and conditions without departing from the spirit and scope of the present invention. Thus, various modifications of the embodiments of the present invention, in addition to those shown and described herein, will be apparent to those skilled in the art from the foregoing description. Such modifications are also intended to fall within the scope of the appended claims.

[0085] The compositions in Table 5 were analyzed in the examples, and iodometric titrations were performed to determine the peracetic acid and hydrogen peroxide content using the procedure described in QATM 317. This method involves two steps to measure peracetic acid and hydrogen peroxide content. The first step is an iodometric titration, suppressing the oxidizing properties of hydrogen peroxide through dilution and low temperature (ice water; the presence of ice does not interfere with the titration chemistry in the reaction flask). In the second step, the same sample is used to measure the hydrogen peroxide content by adding sulfuric acid and a molybdenum catalyst, reagents that rapidly accelerate the oxidation of iodide to hydrogen peroxide. The hydrogen peroxide concentration is determined by taking the difference between the volume of titrant used for the peracetic acid endpoint and the volume required to reach the hydrogen peroxide endpoint.

[0086] 1. Titration of Peracetic Acid: Dispense the peracetic acid sample into a 250 mL Erlenmeyer flask. Add approximately 200 mL of ice water (0°C to 10°C) to the flask. Add 2 mL of 2% starch indicator and 5 mL of 10% KI (potassium iodide) to the flask. Place the flask on a stir plate and immediately titrate with 0.1 N sodium thiosulfate to a colorless endpoint that lasts at least 20 seconds. Record the volume of the titrant (EP1).

[0087] 2. Hydrogen Peroxide Titration: Do not refill the buret from the peracetic acid titration. Add 12 mL of 9 N sulfuric acid and 10-15 drops of 1 N ammonium molybdate to the flask. The solution will return to a blue-black color. Titrate to a second colorless endpoint, lasting at least 20 seconds. Record the volume of the titrant (EP2).

[0088] The peracetic acid and hydrogen peroxide content is calculated as follows: Peracetic acid content:

number

number

[0089] Example 1 The conductivities of Formulation 1 (ionic compound MgSO4) and Formulation 2 (H2SO4) ionic compounds were compared at a peroxyacetic acid concentration of 120 ppm using various water sources to determine any effect on conductivity. Conductivity was measured with a LMIT09 conductivity measuring device (with temperature compensation capability) manufactured by Ecolab Engineering GmbH, Siegsdorf, Germany.

[0090] The conductivity of peroxycarboxylic acid formulations using various water sources was compared and the results are shown in Table 6. Oxonia Active (5.25–6.4% POAA, 25.6–29.4% H2O2) was used as a positive control for comparison. [Table 8]

[0091] For waters above 17 grains, 500 ppm NaHCO3 was added to the 17 grain water to provide an increased water hardness threshold for conductivity measurements. As indicated, the conductivity of the water alone was tested first. The conductivity of the control, Formula 1, and Formula 2 was then tested, with the data in parentheses indicating the difference between the evaluated formula and the water.

[0092] The results show that using DI (deionized) water, the control, Formula 1, and Formula 2 detected active concentrations of peroxyacetic acid. However, when using soft water and 5 grains, only Formulas 1 and 2, which contain ionic compounds, were able to accurately measure concentrations by conductivity, as evidenced by a difference of more than 0.1 mS / cm. The results show that water with very high levels of hardness and alkalinity, 17 grains or more, was able to achieve the conductivity of Formula 1.

[0093] Example 2 Further testing of Formulations 1 and 2 was conducted to evaluate the effect of peroxyacetic acid concentration on conductivity measurements. Measurements were performed at increasing concentrations in 5-grain water. The results are shown in Figures 1 and 2, which show the relationship between peroxyacetic acid concentration and conductivity readings upon dilution with 5-grain water. As demonstrated in the figures, a linear response between peroxyacetic acid concentration and conductivity readings was observed for both Formulations 1 and 2, providing a basis for monitoring peroxyacetic acid concentration by conductivity in use solutions.

[0094] Example 3 After demonstrating the suitability of the ionic compounds in Examples 1 and 2 for conductivity measurements, further testing was performed to confirm that the ionic compounds did not negatively interfere with the antimicrobial effect of the peroxycarboxylic acid.

[0095] Oxonia Active (5.25-6.4% POAA, 25.6-29.4% H2O2) was used as a positive control for comparison, as well as Oxonia Active with added H2SO4 and MgSO4 in separate test formulations. The test concentration (POAA) was identical between Oxonia Active and the H2SO4 and MgSO4 compositions. Formulations 1 and 2 were also analyzed. Staphylococcus aureus and E. coli were exposed to each formulation for 30 seconds. The log reduction of Staphylococcus aureus and E. coli was then measured. ATCC numbers tested ranged from 7-8 logs.

[0096] The results are shown in Figure 3 and show substantially similar performance for all formulations evaluated as measured based on less than a 1 log difference in antimicrobial efficacy compared to the control. All formulations provided greater than a 5 log reduction against both S. aureus and E. coli at a use solution of 105 ppm peroxyacetic acid.

[0097] Example 4 Additional testing was conducted to demonstrate the suitability of the ionic compounds of Examples 1 and 2 over a range of in-use concentrations. Formulations 1 and 2 were again compared to the control Oxonia Active at a concentration of 120 ppm. Test formulations were evaluated at use concentrations of 110 ppm, 120 ppm, and 130 ppm. Pseudomonas aeruginosa was exposed to each formulation for 30 seconds. The log reduction of Pseudomonas aeruginosa was then measured. The results in Figure 4 show that both Formulations 1 and 2 provide equivalent antimicrobial efficacy at use concentrations of 120 ppm and 130 ppm.

[0098] Example 5 Further evaluations were conducted on peroxycarboxylic acid compositions containing compatible ionic compounds to deliver a conductivity signal that allows monitoring of peroxycarboxylic acid concentration by conductivity when diluted for use. These conductivity measurements allow users to determine the concentration of peroxycarboxylic acid at the time of use without a tedious titration step to determine the concentration, providing various advantages during use. As an additional benefit, the use of hydronium salts, e.g., sulfuric acid, offers additional benefits for descaling. Without being limited to a specific mechanism of action, sulfuric acid provides a low pH that prevents and removes mineral scale. Various calcium (Ca) salts in Oxonia Active (5.25-6.4% POAA, 25.6-29.4% H2O2) and Formulation 2 (H2SO4) were used. 2+ Dissolution experiments were conducted to evaluate the solubility of mineral salts. The calcium mineral salts evaluated were calcium phosphate, or hydroxyapatite [Ca(PO)(OH)], and calcium carbonate (CaCO).

[0099] Testing Procedure: 1. Preparation of Test Solutions: Two 100 mL test solutions each of Oxonia Active at concentrations of 0.20%, 0.24%, and 0.28% v / v, and two 100 mL test solutions each of Formulation 2 at concentrations of 0.11%, 0.15%, and 0.20% v / v were prepared in DI water in separate 150 mL beakers. A 1-inch stir bar was placed in each beaker. Each beaker was placed on a stir plate and the solutions were mixed at 300 RPM for a minimum of 1 minute to ensure a homogenous solution was prepared. One set of solutions was allocated for use in combination with calcium phosphate salts (Oxonia Active: 0.20%, 0.24%, and 0.28 v / v%; Formulation 2: 0.11%, 0.15%, and 0.20 v / v%), and the other set of solutions was allocated for use in combination with calcium carbonate salts (Oxonia Active: 0.20%, 0.24%, and 0.28 v / v%; Formulation 2: 0.11%, 0.15%, and 0.20 v / v%).

[0100] 2. Add Calcium Mineral Salt: Add 2-5 grams of the desired calcium salt to the solution. Continue adding calcium salt until the solution cannot dissolve any more (solution becomes cloudy). Stir the solution at 300 RPM for 5 minutes. Do not apply heat to the solution.

[0101] 3. Filtration of undissolved calcium salts: After 5 minutes, extract approximately 20 mL of the solution through a 30 mL plastic syringe (Luer-Lok™ Tip REF305618). Attach a 0.45 μm syringe filter (VWR® Syringe Filter, 25 mm, 0.45 μm nylon membrane) to the tip of the syringe and collect the filtered solution in a small sample container.

[0102] 4. Quantification of calcium in solution: Analyze the filtered solutions using ICP-MS (inductively coupled plasma mass spectrometry) to quantify the calcium dissolved in each solution.

[0103] Results and Discussion: Solutions of Oxonia Active and Formula 2 were analyzed via ICP-MS to quantify the amount of calcium dissolved by the addition of calcium phosphate or calcium carbonate. The concentrations selected for Oxonia Active and Formula 2 represent concentrations that achieve microbial efficacy for food contact sanitization while remaining below the EPA allowable no-clean concentrations for all ingredients included in the formulation (40 CFR § 180.940). Formula 2 was observed to dissolve significantly more calcium salts (both calcium phosphate and calcium carbonate) at lower concentrations than Oxonia Active. At an equivalent concentration of 0.20% v / v, the Formula 2 solution contained 342 mg / L of calcium due to the addition of calcium phosphate, while the Oxonia Active solution contained only 44 mg / L of calcium (Figure 5). Similarly, at an equivalent concentration of 0.20% v / v, the solution of Formulation 2 contained 428 mg / L of calcium due to the addition of calcium carbonate, while the solution of Oxonia Active contained only 78 mg / L of calcium (Figure 6).

[0104] The above results demonstrate that Formulation 2 is significantly more capable of assisting in mineral soil removal of common mineral soils found in food and beverage manufacturing environments (hard water scale from calcium carbonate and stalactite from calcium phosphate) than standard peroxyacetic acid disinfecting compositions such as Oxonia Active. The increased ability of calcium solubility in Formulation 2 may allow for a reduction in the frequency of acid washes to remove mineral scale.

[0105] Example 6 A self-accelerating decomposition test (SADT) evaluation was performed. SADT refers to the lowest temperature at which self-accelerating decomposition can occur in a peroxycarboxylic acid composition. In some embodiments, SADT refers to the lowest temperature at which self-accelerating decomposition can occur under commercial packaging, storage, transportation, and / or use conditions. SADT can be estimated, calculated, predicted, and / or measured by any suitable method. The complete test protocol used in this example is available in "Recommendations on the Transport of Dangerous Goods," Manual of Tests and Criteria, 5th revised edition (United Nations), Classification procedures, test methods, and criteria relating to self-reactive substances of Division 4.1 and organic peroxides of Division 5.2, Test H.4 Heat accumulation storage test (28.4.4).

[0106] Because peroxycarboxylic acids fall into the organic peroxide category and are therefore self-reactive and self-heating products, a test was conducted to demonstrate whether refrigeration is necessary for a given package of peroxycarboxylic acid products. This test modeled a large-volume package with a Dewar flask. In this example, a 50°C oven temperature was used with a spherical Dewar with three rods, a 1.0 L volume, and a heat transfer coefficient of 40 mW / KgK (equivalent to a 300-gallon tote of peroxycarboxylic acid). Each sample volume was 800 mL (952 grams). The Dewar flask was filled to 80% full with product, fitted with a specific lid and a recording thermometer, and placed in an oven set at 50°C. When the temperature inside the package rose to 48°C, a time recording began. If the temperature exceeded the 50°C oven temperature by 6°C before the end of seven days, the SADT of the product was defined as <55°C. If the temperature did not exceed the oven temperature by a 6°C increase, the SADT was considered >55°C, and shipping and storage without refrigeration could be considered.

[0107] The results are shown in Figure 7, where the top line shows the oven temperature and the bottom line shows the temperature of the sample composition.

[0108] Example 7 Hydrogen peroxide (H2O 2) The stability of peroxycarboxylic acid (POAA) compositions containing ionic peroxyacetic acid (APOA) was evaluated at 40°C and 54°C to ensure that POAA and H2O2 concentrations did not decrease over time, indicating that the presence of ionic compounds adversely affected the stability of the compositions. To predict the stability of POAA and H2O2 in concentrates, accelerated stability testing was performed according to EPA recommendations (Guidelines 830.6317 and 830.6320). The EPA recommends incubating solutions at elevated temperatures for various periods (4 weeks at 40°C or 2 weeks at 54°C) to assess the long-term stability of active antimicrobial ingredients. These conditions are accepted as predictors of 12-month room temperature stability.

[0109] Samples of Formulation 2 were prepared and stored at 40°C for 4 weeks. POAA and H2O2 concentrations were measured via iodometric titration at the beginning and end of the incubation period. After 4 weeks of incubation at 40°C, the measured losses in POAA and H2O2 concentrations were 1.74% and 2.69%, respectively.

[0110] Three samples of Formulation 2 were prepared and stored at 54°C for two weeks. POAA and H2O2 concentrations were measured via iodometric titration at the beginning and end of the incubation period. After two weeks of incubation at 54°C, the maximum loss of POAA and H2O2 concentrations measured in all three samples was 6.79% and 5.53%, respectively.

[0111] While the present invention has been described in conjunction with its detailed description, it should be understood that the foregoing description is intended to be illustrative, and not limiting, of the scope of the invention, which is defined by the appended claims. Other embodiments, advantages, and modifications are within the scope of the following claims. Furthermore, the contents of all patent publications discussed above are incorporated by this reference in their entirety.

[0112] The features disclosed in the foregoing description, or in the following claims, or the accompanying drawings, whether presented in a particular form or in terms of means for performing a disclosed function, or a method or process for achieving a disclosed result, may be utilized, separately or in any combination of such features, as appropriate, to realize the invention in diverse forms thereof.

Claims

1. 1. A method for monitoring a peroxycarboxylic acid concentration, the method comprising: providing a use solution of a peroxycarboxylic acid or a peroxycarboxylic acid composition comprising at least about 5% by weight of an ionic compound; contacting a conductivity probe or sensor with the use solution; and detecting a conductivity signal to determine the concentration of peroxycarboxylic acid in the use solution.

2. 10. The method of claim 1, wherein the peroxycarboxylic acid composition is formed by combining a C1 to C22 carboxylic acid with hydrogen peroxide, and the peroxycarboxylic acid is a C1 to C22 peroxycarboxylic acid.

3. 3. The method of claim 1, wherein the ionic compound is a magnesium, aluminum, or hydronium salt that is compatible with peroxycarboxylic acid.

4. 4. The method of claim 3, wherein the ionic compound is magnesium sulfate or sulfuric acid.

5. 5. The method of any one of claims 1 to 4, wherein the ratio of the ionic compound to the peroxycarboxylic acid is from about 5:1 to about 1:5 to ensure adequate conductivity readings.

6. 6. The method of any one of claims 1 to 5, wherein the peroxycarboxylic acid composition comprises a stabilizer, and the ratio of the stabilizer to the ionic compound is from about 1:8 to about 1:

15.

7. 7. The method of any one of claims 1 to 6, wherein the pH of the peroxycarboxylic acid or peroxycarboxylic acid composition use solution is from about 2 to about 9, or less than 5.

8. 8. The method of any one of claims 1 to 7, wherein the peroxycarboxylic acid is peroxyacetic acid, or the peroxycarboxylic acid composition comprises peroxyacetic acid, acetic acid, hydrogen peroxide, and water.

9. 9. The method of any one of claims 1 to 8, wherein detecting the conductivity signal is before or after application of the use solution to a surface in need of cleaning, disinfecting, and / or sanitizing.

10. 1. A method for cleaning, disinfecting, and / or sterilizing a surface, said method comprising: providing a use solution of a peroxycarboxylic acid or peroxycarboxylic acid composition comprising at least about 5% by weight of an ionic compound for conductivity monitoring to a surface in need of cleaning, disinfecting, and / or sanitizing; contacting a conductivity probe or sensor with the use solution; detecting a conductivity signal to determine the concentration of peroxycarboxylic acid in the use solution; removing dirt, scale and / or biofilm from said surface in need of cleaning or disinfecting and / or sterilizing said surface.

11. 11. The method of claim 10, wherein the peroxycarboxylic acid composition is formed by combining a C1 to C22 carboxylic acid, hydrogen peroxide, and the peroxycarboxylic acid is a C1 to C22 peroxycarboxylic acid.

12. 12. The method of claim 10 or 11, wherein the ionic compound is a magnesium, aluminum, or hydronium salt that is compatible with peroxycarboxylic acid, preferably the ionic compound is magnesium sulfate or sulfuric acid.

13. 13. The method of any one of claims 10-12, wherein the ratio of the ionic compound to the peroxycarboxylic acid is from about 5:1 to about 1:5 to ensure a sufficient conductivity reading to ensure a sufficient concentration of the peroxycarboxylic acid is administered for the cleaning, disinfecting, and / or sanitizing of the surface.

14. 14. The method of any one of claims 10 to 13, wherein the peroxycarboxylic acid composition comprises a stabilizer, and the ratio of the stabilizer to the ionic compound is from about 1:8 to about 1:15, and / or the pH of the peroxycarboxylic acid or peroxycarboxylic acid composition is from about 2 to about 9, or less than 5.

15. The method of any one of claims 10 to 14, wherein the peroxycarboxylic acid composition is phosphorus-free.

16. 1. A peroxycarboxylic acid forming composition with conductivity monitoring capability, comprising: a C1 to C22 carboxylic acid; a source of hydrogen peroxide; Water and an ionic compound comprising a magnesium salt, an aluminum salt, or a hydronium salt that is compatible with the peroxycarboxylic acid; a stabilizer, A peroxycarboxylic acid forming composition wherein a C1-C22 peroxycarboxylic acid is formed and the ratio of said ionic compound to said peroxycarboxylic acid is about 5:1 to 1:5 to ensure a detectable conductivity signal.

17. 17. The composition of claim 16, wherein the carboxylic acid is acetic acid, the stabilizers are dipicolinic acid and phosphonic acid, and the composition meets organic certification requirements.

18. 18. The composition of claim 16 or 17, wherein the ionic compound is magnesium sulfate or sulfuric acid.

19. 19. The composition of any one of claims 16-18, wherein the C1-C22 carboxylic acid comprises about 10-50% by weight, the hydrogen peroxide source comprises about 10-70% by weight, the water comprises about 0.1-20% by weight, the ionic compound comprises about 5-50% by weight, and the stabilizer comprises about 0-5% by weight.

20. 1. A peroxycarboxylic acid composition with conductivity monitoring capability, comprising: about 5-20% by weight peracetic acid; about 15 to 40% by weight of acetic acid; about 5 to 50% by weight hydrogen peroxide; Water and about 5 to 50 weight percent of an ionic compound comprising a magnesium salt, an aluminum salt, or a hydronium salt that is compatible with the peroxycarboxylic acid; and about 0.001 to 5 weight percent of a stabilizer.

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