Mass spectrometry method for fluoroether compound

Abstract

To provide a mass spectrometry method capable of detecting a fluoroether compound with high sensitivity.SOLUTION: A mass spectrometry method for a fluoroether compound comprises (1) preparing a sample solution containing a fluoroether compound and a solvent, (2) generating ions by ionizing the fluoroether compound in the sample solution and removing the solvent; (3) specifying a mass of the ions by performing mass separation of the ions. The mass spectrometry method comprises generating droplets by spraying the sample solution with spray gas of 330°C or less when generating the ions, and bringing the generated droplets into contact with drying gas of 190°C or less.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present disclosure relates to a method for mass spectrometry of fluoroether-based compounds. [Background technology]

[0002] Patent Document 1 describes a method for analyzing low-molecular-weight organic compounds having 20 or less carbon atoms in a water / oil repellent composition, which comprises the following steps. (a) A step of mixing a water / oil repellent composition in which a fluorine-containing polymer having a repeating unit based on a compound having a perfluoroalkyl group is dispersed or dissolved in a medium with an alcohol having 1 to 5 carbon atoms to coagulate the fluorine-containing polymer and obtain a liquid containing coagulates of the fluorine-containing polymer. (b) A step of subjecting the liquid containing the fluoropolymer aggregates to solid-liquid separation to obtain a liquid phase. (c) measuring the concentration of low-molecular-weight organic compounds having 20 or less carbon atoms in the liquid phase using a liquid chromatograph-mass spectrometer, a liquid chromatograph-tandem mass spectrometer, or a gas chromatograph-mass spectrometer;

[0003] In Non-Patent Document 1, when 2,3,3,3-tetrafluoro-2-(1,1,2,2,3,3,3-heptafluoropropoxy)propanoic acid (HFPO-DA) is analyzed by liquid chromatography-tandem mass spectrometry (LC-MS / MS) using ammonium bicarbonate as an additive in the mobile phase, the fragmentation of HFPO-DA is suppressed, and [MH] - While the detection sensitivity of bicarbonate adduct [M+HCO3] is improved, - It has been reported that the bicarbonate adduct [M + HCO3] - It is described that the identity of and the fragmentation of HFPO-DA were confirmed. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2009 / 081822 [Non-patent literature]

[0005] [Non-Patent Document 1] “Reduction of LC / MS In-Source Fragmentation of HFPO-DA (GenX) Through Mobile Phase Additive Selection: Experiments to Increase [MH]- Formation” [online], September 26, 2018, United States Environmental Protection Agency, [Retrieved November 25, 2021], Internet<https: / / cfpub.epa.gov / si / si_public_record_report.cfm?dirEntryId=342415> Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present disclosure is to provide a mass spectrometry method capable of detecting fluoroether compounds with high sensitivity. [Means for solving the problem]

[0007] According to the present disclosure, there is provided a mass spectrometry method for a fluoroether compound, comprising: (1) preparing a sample solution containing a fluoroether compound and a solvent; (2) ionizing the fluoroether compound in the sample solution and removing the solvent to generate ions; and (3) performing mass separation of the ions to identify the masses of the ions. In generating the ions, the mass spectrometry method includes spraying the sample solution with a spray gas at 330°C or lower to generate droplets, and contacting the generated droplets with a dry gas at 190°C or lower. Effect of the Invention

[0008] According to the present disclosure, it is possible to provide a mass spectrometry method capable of detecting a fluoroether compound with high sensitivity. [Brief description of the drawings]

[0009] [Figure 1] 1 is a chromatogram obtained by liquid chromatography mass spectrometry in Experimental Example 5. The horizontal axis represents retention time (min), and the vertical axis represents relative peak intensity. [Diagram 2] 2 is a chromatogram obtained by liquid chromatography mass spectrometry in Experimental Example 6. The horizontal axis represents retention time (minutes), and the vertical axis represents relative peak intensity. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The measurement target in the analysis method described in Patent Document 1 is, for example, perfluorocarboxylic acid such as perfluorooctanoic acid (PFOA). When a fluoroether-based compound is the measurement target, there is a problem that the fluoroether-based compound cannot be detected with high sensitivity even if a conventional mass spectrometry method for analyzing perfluorocarboxylic acid or the like is directly applied.

[0011] The measurement target in the analytical method described in Non-Patent Document 1 is HFPO-DA, but the fragmentation of HFPO-DA and the generation of adducts are suppressed, and [MH] - Further improvements for detecting with high sensitivity are desired.

[0012] An object of the present disclosure is to provide a mass spectrometry method capable of detecting fluoroether compounds with high sensitivity.

[0013] Specific embodiments of the present disclosure will be described in detail below, but the present disclosure is not limited to the following embodiments.

[0014] A method for mass spectrometry of a fluoroether-based compound according to an embodiment of the present disclosure includes the steps of: 1) preparing a sample solution containing a fluoroether compound and a solvent; 2) ionizing a fluoroether compound in the sample solution and removing the solvent to generate ions; 3) identifying the masses of the ions by mass separation of the ions; Includes.

[0015] In step (1), a sample solution containing a fluoroether compound and a solvent is prepared.

[0016] There are no particular limitations on the type of fluoroether compound, and any organic compound having two or more carbon atoms that contains one or more fluorine atoms and one or more ether bonds can be used as a measurement target in the mass spectrometry method of the present disclosure.

[0017] Examples of the fluoroether-based compound include polyoxyfluoroalkylene fluoroalkyl ether, fluoroether carboxylic acid, and fluoroether sulfonic acid.

[0018] More specific examples of the fluoroether-based compound include perfluoroether carboxylic acid (III) represented by the following general formula (III), perfluoroalkoxy fluorocarboxylic acid (V) represented by the following general formula (V), fluorocarboxylic acid (X) represented by the following general formula (X), alkoxy fluorosulfonic acid (XI) represented by the following general formula (XI), compound (XII) represented by the following general formula (XII), compound (XIII) represented by the following general formula (XIII), and compound (XIV) represented by the following general formula (XIV).

[0019] The perfluoroether carboxylic acid (III) is represented by the following general formula (III): Rf 1 -O-(CF(CF3)CF2O) n3 CF(CF3)COOM (III) (In the formula, Rf 1 is a perfluoroalkyl group having 1 to 5 carbon atoms, n3 is an integer of 0 to 3, and M is H, a metal atom, or NR 7 4. An imidazolium which may have a substituent, a pyridinium which may have a substituent, or a phosphonium which may have a substituent, R 7 is H or an organic group.

[0020] The alkoxyfluorocarboxylic acid (V) is represented by the following general formula (V): Rf 4 -O-CY 1 Y 2 -(CF2) m -COOM (V) (In the formula, Rf 4 is a linear or branched, partially or completely fluorinated alkyl or alkenyl group having 1 to 12 carbon atoms, which may contain an ether bond and / or a chlorine atom; Y 1 and Y 2 are the same or different and are H, F or CF3, m is 0 or 1, and M is as defined above.

[0021] The fluorocarboxylic acid (X) is represented by the following general formula (X): Rf 7 -O-Rf 8 -O-CF2-COOM (X) (In the formula, Rf 7 is a linear or branched partially or fully fluorinated alkyl group having 1 to 6 carbon atoms, which may contain an ether bond and / or a chlorine atom; Rf 8 is a linear or branched, partially or fully fluorinated alkyl group having 1 to 6 carbon atoms, and M is as defined above.

[0022] The alkoxyfluorosulfonic acid (XI) is represented by the following general formula (XI): Rf 9 -O-CY 1 Y 2 -(CF2) m -SO3M (XI) (In the formula, Rf 9 is a linear or branched, partially or completely fluorinated alkyl or alkenyl group having 1 to 12 carbon atoms, which may contain an ether bond and / or a chlorine atom; Y 1 and Y 2 are the same or different and are H, F or CF3, m is 0 or 1, and M is as defined above.

[0023] The compound (XII) is represented by the following general formula (XII): [ka] (In the formula, X 1 , X 2 and X 3 Rf may be the same or different and are H, F or a linear or branched partially or completely fluorinated alkyl group having 1 to 6 carbon atoms, which may contain an ether bond; 10 is a perfluoroalkylene group having 1 to 3 carbon atoms, L is a linking group, and Y 0 is an anionic group. Y 0 may be -COOM, -SO2M, or -SO3M, or may be -SO3M or COOM, where M is as defined above. Examples of L include a single bond and a partially or completely fluorinated alkylene group having 1 to 10 carbon atoms which may contain an ether bond.

[0024] The compound (XIII) is represented by the following general formula (XIII): Rf 11 -O-(CF2CF(CF3)O) n9 (CF2O) n10 CF2COOM (XIII) (In the formula, Rf 11 is a fluoroalkyl group containing chlorine and having 1 to 5 carbon atoms, n9 is an integer of 0 to 3, n10 is an integer of 0 to 3, and M is as defined above.) Compound (XIII) is represented by CF2ClO(CF2CF(CF3)O)n9 (CF2O) n10 CF2COONH4 (a mixture having an average molecular weight of 750, where n9 and n10 are defined above).

[0025] The compound (XIV) is represented by the following general formula (XIV): CX i X k =CX j R a -(CZ 1 Z 2 ) k -Y 0 (XIV) (In the formula, X i , X j and X k may be the same or different and are F, Cl, H or CF3; Y 0 is SO3M or COOM; R a is a linking group; Z 1 and Z 2 may be the same or different and are H, F or CF3, k is 0 or 1, and M is as defined above.

[0026] As the fluoroether-based compound, a compound that is difficult to detect with high sensitivity by conventional mass spectrometry methods and for which the mass spectrometry method of the present disclosure is highly effective can be preferably used. For example, a compound represented by the general formula: [ka] (In the formula, R 1 is H-, F-, Cl-, CH2=CH-, CH2=CF-, CF2=CF- or CF2=CFO-, and R 2 is COO or SO3, a to g may be the same or different and each is an integer of 0 or more, the sum of a to g is 0 or an integer of 1 or more, and when the sum of a to g is 0, R 1 CF2=CFO-, X 4 and X 5are independently H, F or CF3, n is an integer of 1 or more, and M is a cation) are preferably used.

[0027] In the above general formula, the order of the repeating units is arbitrary, and X 4 and X 5 may be the same or different in each occurrence.

[0028] a to g may be the same or different and each is an integer of 0 or more, preferably an integer of 0 to 2, and more preferably 0 or 1. The sum of a to g is 0 or an integer of 1 or more, preferably an integer of 1 to 5, more preferably an integer of 1 to 3, further preferably 1 or 2, and particularly preferably 1. n is preferably an integer of 1 to 3, more preferably 1 or 2, and further preferably 1.

[0029] In one embodiment of the fluoroether compound, g is 0, and a to f may be the same or different and are each an integer of 0 or more, and the sum of a to f is an integer of 1 or more. In one embodiment of the fluoroether compound, g is 0, and a to f may be the same or different and each is an integer of 0 or more, preferably an integer of 0 to 2, and more preferably 0 or 1. In one embodiment of the fluoroether compound, g is 0, and the sum of a to f is an integer of 1 or more, preferably an integer of 1 to 5, more preferably an integer of 1 to 3, even more preferably 1 or 2, and particularly preferably 1. In one embodiment of the fluoroether compound, g is 0, and n is preferably an integer of 1 to 3, more preferably 1 or 2, and further preferably 1.

[0030] M is H, a metal atom, or NR 7 4(R 7is H or an organic group), optionally substituted imidazolium, optionally substituted pyridinium or optionally substituted phosphonium is preferred, and H, a metal atom or NR 7 4 is more preferred, H, an alkali metal (group 1), an alkaline earth metal (group 2) or NR 7 More preferred is 4, with H, Na, K, Li or NH4 being especially preferred.

[0031] As the fluoroether-based compound, among others, the compound represented by the following formula is particularly preferred because it is a compound that is difficult to detect with high sensitivity by conventional mass spectrometry methods and is a compound in which the effects of the mass spectrometry method of the present disclosure can be greatly exhibited. CF3O(CF2)3OCHFCF2COOM, C3F7OCF(CF3)CF2OCF(CF3)COOM, CF3CF2CF2OCF(CF3)COOM, CF3CF2OCF2CF2OCF2COOM, C2F5OCF(CF3)CF2OCF(CF3)COOM, CF3OCF(CF3)CF2OCF(CF3)COOM, CF2ClCF2CF2OCF(CF3)CF2OCF2COOM, CF2ClCF2CF2OCF2CF(CF3)OCF2COOM, CF2ClCF(CF3)OCF(CF3)CF2OCF2COOM, CF2ClCF(CF3)OCF2CF(CF3)OCF2COOM, CF2=CFOCF2CF(CF3)OCF2CF2COOM, CF2=CFOCF2CF(CF3)OCF2CF2SO3M, CF2 = CFOCF2CF2SO3M, CF2 = CFOCF2CF2COOM, CH2 = CFCF2OCF(CF3)COOM, CH2=CFCF2OCF(CF3)CF2OCF(CF3)COOM (In each formula, M is H, metal atom, NR7 4. An optionally substituted imidazolium, an optionally substituted pyridinium, or an optionally substituted phosphonium, wherein R 7 is H or an organic group.

[0032] The solvent is preferably a volatile solvent that can be easily removed in step (2) and can easily generate only the ions to be subjected to mass separation. Examples of the solvent include solvents commonly used in liquid chromatography mass spectrometry, such as alcohols such as methanol, ethanol, and isopropyl alcohol, acetonitrile, and water.

[0033] In one embodiment, the sample solution is a sample solution whose components have been separated by liquid chromatography. When preparing the sample solution using liquid chromatography, step (1) can include, for example, a step of feeding a sample containing a fluoroether compound together with a mobile phase into a column, separating the components while passing through the column, and eluting the separated eluate from the column as the sample solution.

[0034] In one embodiment, component separation using liquid chromatography can be performed in a liquid chromatography section (LC section) of a liquid chromatography mass spectrometer. Such a liquid chromatography mass spectrometer includes, for example, an LC section that separates components of a sample solution by liquid chromatography, an ionization section that ionizes and desolvates components in the sample solution, a mass separation section that separates ions according to their mass-to-charge ratios, and an ion detection section that detects the separated ions.

[0035] Liquid chromatography includes reverse phase chromatography, normal phase chromatography, hydrophilic interaction chromatography, ion exchange chromatography, size exclusion chromatography, etc. In one embodiment, reverse phase chromatography is used.

[0036] When performing liquid chromatography, an isocratic method using a single mobile phase or a gradient method in which the composition of the mobile phase is continuously changed can be used. In one embodiment, liquid chromatography is performed using water and methanol or water and acetonitrile as the mobile phase, while continuously changing the composition of water and methanol or the composition of water and acetonitrile in the mobile phase.

[0037] It is also preferable to adjust the pH of the sample solution. The pH of the sample solution may be, for example, less than 8. In one embodiment, the pH is adjusted by adjusting the pH of the mobile phase fed into the liquid chromatography so that the pH of the eluent falls within a desired range. To adjust the pH of the mobile phase, for example, a pH adjuster such as an acid such as formic acid or acetic acid, an ammonium salt such as ammonium formate, ammonium acetate, ammonium bicarbonate, or ammonium hydroxide, or ammonia can be used.

[0038] In step (2), the fluoroether compounds in the sample solution are ionized and the solvent is removed to generate ions.

[0039] In one embodiment, ions are generated in an ionization section of a liquid chromatography mass spectrometer. In step (1), when liquid chromatography is performed, the eluate eluted from the column can be introduced into the ionization section as a sample solution. For ionization, for example, a method in which ionization is performed under atmospheric pressure is preferably used.

[0040] The ionization unit is compatible with electrospray ionization (ESI), atmospheric pressure chemical ionization (APCI), etc. In one embodiment, ions are generated using electrospray ionization (ESI).

[0041] In the electrospray ionization method, charged droplets are generated and then dried to ionize the sample molecules. When generating droplets, the sample solution is dispersed by electrospray. In this case, the generation of droplets is promoted by using an inert gas such as nitrogen as a nebulizer gas. In addition, desolvation from the droplets is promoted by spraying the sample solution together with the nebulizing gas. The nebulizing gas may be called a sheath gas, desolvation gas, auxiliary gas, heater gas, turbo gas, etc. Furthermore, desolvation and drying of the droplets are further promoted by contacting the droplets with a drying gas. The drying gas may be called a sweep gas, cone gas, etc.

[0042] In step (2), the sample solution is sprayed with a nebulizing gas at 330° C. or less to generate droplets, and the generated droplets are brought into contact with a drying gas at 190° C. or less, thereby enabling detection of fluoroether compounds with high sensitivity. In conventional mass spectrometry methods, the generated droplets are usually actively vaporized at high temperatures in order to efficiently evaporate them, and the remarkable improvement in detection sensitivity achieved by controlling the temperatures of the nebulizing gas and drying gas low is an unexpected and surprising effect.

[0043] The temperature of the spray gas may be, for example, 100 to 330° C. The temperature of the spray gas is preferably 310° C. or less, more preferably 300° C. or less, preferably 130° C. or more, more preferably 140° C. or more, and even more preferably 150° C. or more, because this further improves the detection sensitivity of fluoroether-based compounds.

[0044] The temperature of the nebulizer gas can be adjusted by adjusting parameters called sheath gas temperature, vaporizer temperature, desolvation gas temperature, ESI heater temperature, source temperature, turbo temperature, HSID temperature, and the like.

[0045] The temperature of the dry gas may be, for example, 80 to 190° C. The temperature of the dry gas is preferably 175° C. or less, more preferably 165° C. or less, and even more preferably 155° C. or less, since this further improves the detection sensitivity of the fluoroether-based compounds.

[0046] The temperature of the drying gas can be adjusted by adjusting parameters called ion transfer temperature, source temperature, block heater temperature, desolvation line temperature, source temperature, dry heater temperature, and the like.

[0047] Other ionization conditions can be the same as those normally set for measurements using a liquid chromatography mass spectrometer. For example, when using an Agilent mass spectrometer, each condition can be set in the following ranges: Spray gas flow rate: 2~12L / min Drying gas flow rate: 3~13L / min Sample solution supply flow rate: 50 to 1000 μL / min Voltage applied when generating ions: 300 to 6000 V Nebulizer gas pressure: 30-60psi

[0048] In step (3), the ions generated in step (2) are subjected to mass separation to identify the masses of the ions.

[0049] In one embodiment, the mass of an ion is identified by separating ions by mass according to their mass-to-charge ratio in a mass separation section and an ion detection section of a liquid chromatography mass spectrometer, and detecting the separated ions.

[0050] The mass separator may be a quadrupole mass separator, an ion trap mass separator, a magnetic sector mass separator, a time-of-flight mass separator, or the like. Mass separators of the same type or different types may be connected together and used (tandem mass spectrometer (MS / MS)). In one embodiment, the mass analysis method of the present disclosure is carried out using a liquid chromatography tandem mass spectrometer (LC-MS / MS).

[0051] According to the mass spectrometry method of the present disclosure, in step (3), a precursor ion having the general formula: [ka] (In the formula, R 1 , R 2 , a~g, X 4 , X 5 and n are as defined above. The order of the repeating units is arbitrary. X 4 and X 5 may be the same or different in each occurrence.) can be used. In conventional methods, since such ions cannot be detected with high sensitivity (only a very weak signal is shown), it has been attempted to analyze the mass of a fluoroether-based compound by detecting fragment ions (for example, fragment ions generated by the detachment of some atomic groups such as COO) instead. However, in such methods, the possibility that the fragment ions are generated from another compound cannot be denied, and the detection sensitivity is not sufficient, making accurate analysis difficult. According to the mass spectrometry method of the present disclosure, the above ions can be directly detected with high sensitivity, so that the mass of a fluoroether-based compound can be accurately measured.

[0052] In the mass spectrometry method of the present disclosure, by using a sample solution containing, in addition to a fluoroether-based compound and a solvent, a fluorine-containing compound other than the fluoroether-based compound, it is possible to simultaneously identify not only the mass of the fluoroether-based compound but also the mass of the fluorine-containing compound other than the fluoroether-based compound.

[0053] The fluorine-containing compound (fluorine-containing compound other than fluoroether-based compounds) that may be included in the mass spectrometry method of the present disclosure is not particularly limited as long as it contains one or more fluorine atoms and does not contain an ether bond. For example, perfluorocarboxylic acids such as perfluorobutanoic acid, perfluoropentanoic acid, perfluorohexanoic acid, perfluoroheptanoic acid, perfluorooctanoic acid, perfluorononanoic acid, perfluorodecanoic acid, perfluoroundecanoic acid, perfluorododecanoic acid, perfluorotridecanoic acid, and perfluorotetradecanoic acid; Fluorocarboxylic acids in which some of the fluorine atoms in perfluorocarboxylic acids have been replaced with hydrogen atoms; perfluorosulfonic acids, such as perfluorobutanesulfonic acid, perfluoropentanesulfonic acid, perfluorohexanesulfonic acid, perfluoroheptanesulfonic acid, perfluorooctane sulfonic acid, perfluorononanesulfonic acid, perfluorodecanesulfonic acid, perfluoroundecanesulfonic acid, perfluorododecanesulfonic acid, perfluorotridecanesulfonic acid, and perfluorotetradecanesulfonic acid; Fluorosulfonic acids in which some of the fluorine atoms in perfluorosulfonic acids have been replaced with hydrogen atoms, such as 1H,1H,2H,2H-perfluorohexanesulfonic acid, 1H,1H,2H,2H-perfluorooctanesulfonic acid, and 1H,1H,2H,2H-perfluorodecanesulfonic acid; Derivatives of perfluorocarboxylic or perfluorosulfonic acids, such as 2-(N-methylperfluorooctanesulfonamido)acetic acid, 2-(N-ethylperfluorooctanesulfonamido)acetic acid; etc.

[0054] Although the embodiments have been described above, it will be understood that various changes in form and details are possible without departing from the spirit and scope of the claims.

[0055] <1> According to a first aspect of the present disclosure, 1) preparing a sample solution containing a fluoroether compound and a solvent; 2) ionizing the fluoroether compound in the sample solution and removing the solvent to generate ions; 3) Identifying the mass of the ions by mass separation of the ions. A method for mass spectrometry of a fluoroether compound, comprising the steps of: When generating the ions, The sample solution is sprayed together with a spray gas at 330° C. or less to generate droplets, and the generated droplets are brought into contact with a dry gas at 190° C. or less. Mass spectrometry methods. <2> According to a second aspect of the present disclosure, In a first aspect of the present invention, there is provided a mass spectrometry method, wherein the pH of the sample solution is less than 8. <3> According to a third aspect of the present disclosure, There is provided a mass spectrometry method according to the first or second aspect, wherein the pressure at which the ions are generated is atmospheric pressure. <4> According to a fourth aspect of the present disclosure, There is provided a mass spectrometry method according to any one of the first to third aspects, wherein the method for generating ions is electrospray ionization. <5> According to a fifth aspect of the present disclosure, The fluoroether compound has the general formula: [ka] (In the formula, R 1 is H-, F-, Cl-, CH2=CH-, CH2=CF-, CF2=CF- or CF2=CFO-, and R 2 is COO or SO3, a to g may be the same or different and each is an integer of 0 or more, the sum of a to g is 0 or an integer of 1 or more, and when the sum of a to g is 0, R 1 CF2=CFO-, X 4 and X 5are independently H, F or CF3, n is an integer of 1 or more, and M is a cation. <6> According to a sixth aspect of the present disclosure, As a precursor ion, the general formula: [ka] (In the formula, R 1 , R 2 , a~g, X 4 , X 5 and n is as defined above). <7> According to a seventh aspect of the present disclosure, The present invention provides a mass spectrometry method according to any one of the first to sixth aspects, in which a sample solution further containing a fluorine-containing compound other than a fluoroether compound is prepared, and the fluorine-containing compound is added to the fluoroether compound, ionized, and the solvent is removed to generate ions of the fluoroether compound and ions of the fluorine-containing compound, and the mass of the fluorine-containing compound ions is specified in addition to the mass of the fluoroether compound ions. EXAMPLES

[0056] Next, embodiments of the present disclosure will be described with reference to examples, but the present disclosure is not limited to these examples.

[0057] In Experimental Examples 1 to 4, the following equipment was used. (Liquid Chromatography Mass Spectrometer) (LC-MS / MS) LC: Agilent 1290 Infinity II MS: Agilent, Ultivo LC / TQ

[0058] (LC measurement conditions) Column: Agilent, ZORBAX Extend-C18, 2.1 mm x 50 mm, 1.8 μm Mobile phase: (Liquid A) 20 mM ammonium acetate aqueous solution, (Liquid B) LC / MS grade acetonitrile Composition: A liquid: B liquid = 40:60 Sample injection volume: 1μL Flow rate: 200μL / min Column temperature: 40℃

[0059] (MS measurement conditions) Ionization method: Negative ESI <2,3,3,3-tetrafluoro-2-(1,1,2,2,3,3,3-heptafluoropropoxy)propanoic acid> MRM monitor ion: 329.0 → 285.0 Fragmenter voltage: 50V Collision Energy: 1V <pfoa> MRM monitor ion: 413.0 → 369.0 Fragmenter voltage: 110V Collision Energy: 5V 2,3,3,3-Tetrafluoro-2-(1,1,2,2,3,3,3-heptafluoropropoxy)propanoic acid and PFOA were purchased from Fujifilm Wako Pure Chemical Industries, Ltd.

[0060] Experimental Example 1 Experimental Example 1 shows that a very limited range of nebulizer gas temperatures significantly improves the detection sensitivity of fluoroether compounds.

[0061] As a sample (a sample to be injected into liquid chromatography), a 0.1 ppm by mass aqueous solution of 2,3,3,3-tetrafluoro-2-(1,1,2,2,3,3,3-heptafluoropropoxy)propanoic acid was used.

[0062] Using the prepared sample and the above-mentioned liquid chromatography mass spectrometer, mass spectrometry of 2,3,3,3-tetrafluoro-2-(1,1,2,2,3,3,3-heptafluoropropoxy)propanoic acid was performed.

[0063] The ionization conditions in Experimental Example 1 are as follows. Drying gas temperature: 150℃ Drying gas flow rate: 5L / min Atomization gas temperature (sheath gas temperature): As shown in Table 1 Spray gas flow rate: 7.5L / min Nebulizer pressure: 50psi Flag: 50V CE:1V Capillary voltage: as listed in Table 1

[0064] The spectrum obtained is [CF3CF2CF2OCF(CF3)COO] - The detection sensitivity (response) for each ionization condition was determined from the peak area value of the ion corresponding to the mass of the sample. The values ​​calculated assuming the detection sensitivity measured under the conditions of a drying gas temperature of 150°C, a spray gas temperature of 350°C, and a voltage of 1000V as 100 are shown in Table 1.

[0065] [Table 1]

[0066] Experimental Example 2 Experimental Example 2 shows that a very limited range of dry gas temperatures significantly improves the detection sensitivity of fluoroether compounds.

[0067] Using the sample prepared in Experimental Example 1 and the above-mentioned liquid chromatography mass spectrometer, mass analysis of 2,3,3,3-tetrafluoro-2-(1,1,2,2,3,3,3-heptafluoropropoxy)propanoic acid was carried out.

[0068] The ionization conditions in Experimental Example 2 are as follows. Drying gas temperature: as shown in Table 2 Drying gas flow rate: 5L / min Atomization gas temperature: 250℃ Spray gas flow rate: 7.5L / min Nebulizer pressure: 50psi Flag: 50V CE:1V Capillary voltage: as listed in Table 2

[0069] The spectrum obtained is [CF3CF2CF2OCF(CF3)COO] - The detection sensitivity (response) for each ionization condition was determined from the peak area value of the ion corresponding to the mass of the sample. The values ​​calculated assuming the detection sensitivity measured under the conditions of a drying gas temperature of 150°C, a spray gas temperature of 350°C, and a voltage of 1000V as 100 are shown in Table 2.

[0070] [Table 2]

[0071] Experimental Examples 3 and 4 Experimental Examples 3 and 4 show that when the mass of perfluorooctanoic acid (PFOA) is analyzed using the mass spectrometry method of the present disclosure, perfluorooctanoic acid (PFOA) cannot be detected with sufficient sensitivity.

[0072] As a sample (a sample to be injected into liquid chromatography), an aqueous solution of 0.1 ppm by mass of perfluorooctanoic acid (PFOA) was used.

[0073] Using the prepared sample and the above-mentioned liquid chromatography mass spectrometer, mass spectrometry of perfluorooctanoic acid was carried out.

[0074] The ionization conditions in Experimental Example 3 are as follows. Drying gas temperature: 150℃ Drying gas flow rate: 5L / min Atomization gas temperature (sheath gas temperature): As shown in Table 3 Spray gas flow rate: 7.5L / min Nebulizer pressure: 50psi Frag:110V CE:5V Capillary voltage: as described in Table 3

[0075] The spectrum obtained is [CF3(CF2)6COO] - The detection sensitivity (response) for each ionization condition was determined from the peak area value of the ion corresponding to the mass of the sample. The values ​​calculated assuming the detection sensitivity measured under the conditions of a drying gas temperature of 150°C, a spray gas temperature of 350°C, and a voltage of 1000V as 100 are shown in Table 3.

[0076] [Table 3]

[0077] The ionization conditions in Experimental Example 4 are as follows. Drying gas temperature: as listed in Table 4 Drying gas flow rate: 5L / min Atomization gas temperature: 250℃ Spray gas flow rate: 7.5L / min Nebulizer pressure: 50psi Frag:110V CE:5V Capillary voltage: as described in Table 4

[0078] The spectrum obtained is [CF3(CF2)6COO] - The detection sensitivity (response) for each ionization condition was determined from the peak area value of the ion corresponding to the mass of the sample. The values ​​calculated assuming the detection sensitivity measured under the conditions of a drying gas temperature of 150°C, a spray gas temperature of 350°C, and a voltage of 1000V as 100 are shown in Table 4.

[0079] [Table 4]

[0080] In Experimental Examples 5 and 6, the following equipment was used. (Liquid Chromatography Mass Spectrometer) (LC-MS / MS) LC: Agilent 1290 Infinity II MS: Agilent, Ultivo LC / TQ

[0081] (LC measurement conditions) Column: Agilent, ZORBAX Extend-C18, 2.1 mm x 50 mm, 1.8 μm Mobile phase: (Liquid A) 20 mM ammonium acetate aqueous solution, (Liquid B) LC / MS grade acetonitrile Composition: A liquid: B liquid = 80:20 (0-1 min) ↓ (1-6 minutes) 60:40 (6-7 minutes) ↓ (7-12 minutes) 95:5 (12-15 minutes) Sample injection volume: 5μL Flow rate: 300μL / min Column temperature: 40℃

[0082] (MS measurement conditions) Ionization method: Negative ESI

[0083] [Table 5]

[0084] Perfluorobutanoic acid, perfluoropentanoic acid, perfluorohexanoic acid, perfluoroheptanoic acid, perfluorooctanoic acid, perfluorononanoic acid, perfluorodecanoic acid, perfluoroundecanoic acid, perfluorododecanoic acid, perfluorotridecanoic acid, and a mixture of perfluorotetradecanoic acids were purchased from Wellington Labs.

[0085] Experimental Example 5 Experimental Example 5 shows that it is possible to simultaneously measure 2,3,3,3-tetrafluoro-2-(1,1,2,2,3,3,3-heptafluoropropoxy)propanoic acid, perfluorobutanoic acid, perfluoropentanoic acid, perfluorohexanoic acid, perfluoroheptanoic acid, perfluorooctanoic acid, perfluorononanoic acid, perfluorodecanoic acid, perfluoroundecanoic acid, perfluorododecanoic acid, perfluorotridecanoic acid, and perfluorotetradecanoic acid.

[0086] The ionization conditions in Experimental Example 5 are as follows. Drying gas temperature: 150℃ Drying gas flow rate: 5L / min Spray gas temperature (sheath gas temperature): 250℃ Spray gas flow rate: 7.5L / min Nebulizer pressure: 50psi Frag: As described in Table 5 CE: As described in Table 5 Capillary voltage: 2500V

[0087] The sample (injected into the liquid chromatography) was an aqueous solution containing 2,3,3,3-tetrafluoro-2-(1,1,2,2,3,3,3-heptafluoropropoxy)propanoic acid, as well as a mixture of perfluorobutanoic acid, perfluoropentanoic acid, perfluorohexanoic acid, perfluoroheptanoic acid, perfluorooctanoic acid, perfluorononanoic acid, perfluorodecanoic acid, perfluoroundecanoic acid, perfluorododecanoic acid, perfluorotridecanoic acid, and perfluorotetradecanoic acid (each of the 12 compounds contained 0.01 mass ppm). The injection volume was 5 μL. The measurement results are shown in Figure 1.

[0088] Experimental Example 6 In Experimental Example 6, in the simultaneous measurement of 2,3,3,3-tetrafluoro-2-(1,1,2,2,3,3,3-heptafluoropropoxy)propanoic acid and perfluorobutanoic acid, perfluoropentanoic acid, perfluorohexanoic acid, perfluoroheptanoic acid, perfluorooctanoic acid, perfluorononanoic acid, perfluorodecanoic acid, perfluoroundecanoic acid, perfluorododecanoic acid, perfluorotridecanoic acid, and perfluorotetradecanoic acid, it is shown that the detection sensitivity of fluoroether compounds decreases outside the limited dry gas temperature range.

[0089] The measurement was carried out under the same conditions as in Experimental Example 5, except that the drying gas temperature was set to 300° C. The measurement results are shown in Figure 2. It can be seen that the intensity of peak 4 derived from 2,3,3,3-tetrafluoro-2-(1,1,2,2,3,3,3-heptafluoropropoxy)propanoic acid is reduced.< / pfoa>

Claims

1. 1) preparing a sample solution containing a fluoroether compound and a solvent; 2) ionizing the fluoroether-based compound in the sample solution and removing the solvent to generate ions; 3) Identifying the mass of the ions by mass separation of the ions. A method for mass spectrometry of a fluoroether-based compound, When generating the ions, The sample solution is sprayed together with a spray gas at 330°C or less to generate droplets, and the generated droplets are brought into contact with a dry gas at 190°C or less. Mass spectrometry methods.

2. A mass spectrometry method as described in claim 1, wherein the flow rate of the dry gas is 3 to 5 L / min.

3. 3. The mass spectrometry method according to claim 1, wherein the sample solution has a pH of less than 8.

4. 3. The mass spectrometry method according to claim 1, wherein the pressure when generating the ions is atmospheric pressure.

5. 3. The mass spectrometry method according to claim 1, wherein the method for generating ions is electrospray ionization.

6. The fluoroether compound has the general formula: 【Chemistry 6】 (In the formula, R １ is H-, F-, Cl-, CH ２ =CH-, CH ２ =CF-, CF ２ =CF- or CF ２ =CFO-, and R ２ is COO or SO ３ a to g may be the same or different and each is an integer of 0 or more, the sum of a to g is 0 or an integer of 1 or more, and when the sum of a to g is 0, R １ is CF ２ =CFO-, and X ４ and X ５ are independently H, F or CF ３ 3. The mass spectrometry method according to claim 1, wherein the compound is a compound represented by the formula (I) wherein n is an integer of 1 or more, and M is a cation.

7. The precursor ion may be a compound of the general formula: 【Chemistry 7】 (In the formula, R １ , R ２ , a to g, X ４ , X ５ and n is as defined above).

8. 3. The mass spectrometry method according to claim 2, further comprising: preparing a sample solution further containing a fluorine-containing compound other than the fluoroether-based compound; adding the fluoroether-based compound to the sample solution; ionizing the fluorine-containing compound; and removing the solvent to generate ions of the fluoroether-based compound and ions of the fluorine-containing compound; and identifying the mass of the fluorine-containing compound ion in addition to the mass of the fluoroether-based compound ion.

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