Method for detecting sorbitol and mannitol in a coated metal can packaged beverage

Abstract

The application discloses a method for detecting sorbitol and mannitol in a coated metal can packaged beverage, which comprises the following steps: performing solid phase extraction on a sample of the coated metal can packaged beverage to be detected by using a polyamide solid phase extraction column, then adding water to perform elution, and receiving an eluate; diluting the eluate with water and filtering through a filter membrane to obtain a test sample solution; and performing ultra-high performance liquid chromatography-mass spectrometry detection on the test sample solution. The method for detecting sorbitol and mannitol in the coated metal can packaged beverage has simple pretreatment, high accuracy and low detection limit, and can provide good technical support for quality control, safety monitoring and safety supervision of food, food contact coated metal materials and products, and has good economic and social benefits.

Description

Technical Field

[0001] This invention belongs to the field of food analysis technology, and more specifically, this invention relates to a method for detecting sorbitol and mannitol in beverages packaged in coated metal cans. Background Technology

[0002] Sorbitol is an important class of sugar alcohols. Natural sources of sorbitol include various fruits and vegetables such as apples and pears. Sorbitol can also be produced by catalytic hydrogenation of glucose. It can be used as an anti-caries sweetener, a food antifreeze agent, and clinically for treating cerebral edema, glaucoma, and edema with oliguria in patients with normal cardiac and renal function.

[0003] Mannitol and sorbitol are isomers, differing only in the chirality of one carbon atom. Natural mannitol is primarily derived from kelp, mushrooms, and seaweed. Industrial mannitol is mainly produced through the epimerization of glucose followed by hydrogenation. Mannitol is primarily used clinically as a hyperosmolar antihypertensive drug and is less commonly used in food.

[0004] GB 2760-2024, the National Food Safety Standard for the Use of Food Additives, stipulates that sorbitol can be used in various foods such as beverages, dairy products, jams, and candies. Mannitol can be used in candies. Excessive intake of sorbitol can increase the burden on the gastrointestinal tract, leading to digestive disorders, which may cause discomfort such as abdominal pain and diarrhea. It may also lead to water and electrolyte imbalances, abnormal insulin secretion, and allergic reactions. Common hazards of mannitol include allergic reactions and water and electrolyte imbalances.

[0005] GB 9685-2016, the National Food Safety Standard for Additives Used in Food Contact Materials and Articles, stipulates that sorbitol can be used in food contact plastics, adhesives, and paper products, but mannitol is not listed. The European Consumer Health Protection Committee, in its standard "Coatings intended to cominto contact with foodstuffs" (2009), specifies that sorbitol and mannitol can be used in coatings and coatings intended for food contact. Coated metal cans are an important form of beverage packaging; my country produces over 47 billion aluminum cans annually for beer and beverages.

[0006] Several standard or literature methods exist for detecting sorbitol and mannitol in food, but all have limitations. GB 5009.279-2016 provides a high-performance liquid chromatography (HPLC) method for the determination of xylitol, sorbitol, maltitol, and erythritol in food (excluding mannitol). This method uses an amino-coated or cation-exchange column. For non-protein beverages, a pretreatment method of 5-fold dilution with water followed by filtration is used. The detection limit for sorbitol is 0.02 g / 100 g. SN / T 3142-2012 provides a HPLC-MS / MS method for the determination of mannitol, maltose, xylitol, and sorbitol in exported food. This method uses electrospray ionization in negative ion mode and an Agilent ZORBAX sugar analysis column. Beverage samples are pretreated with a 10-fold dilution with water followed by filtration. This method cannot separate mannitol and sorbitol chromatographically, and quantification is difficult when both are present. Hou Shaoping et al. established a method for the determination of five sugars and three sugar alcohols using high performance liquid chromatography-quadrupole mass spectrometry. This method uses an amide column and separates sorbitol and mannitol by adding guanidine hydrochloride and diethylamine to the mobile phase. However, the decomposition products of guanidine hydrochloride and diethylamine are high-boiling-point components, which may damage the mass spectrometer and are not conducive to the practical implementation of the method. Summary of the Invention

[0007] Based on this, the purpose of the present invention is to provide a method for simultaneously detecting sorbitol and mannitol in coated metal can packaged beverages under conventional mobile phase conditions.

[0008] The technical solutions for achieving the above-mentioned objectives include the following.

[0009] A first aspect of the present invention provides a method for detecting sorbitol and mannitol in beverages packaged in coated metal cans, comprising the following steps:

[0010] (1) Transfer the beverage sample in the coated metal can to be tested to a polyamide solid phase extraction column, add water for elution, and collect the eluent; dilute with water and filter through a membrane to obtain the test solution.

[0011] (2) The test solution was detected by ultra-high performance liquid chromatography-mass spectrometry;

[0012] The ultra-high performance liquid chromatography used a Hilic-Diol column. Mobile phase A was 4 mmol / L ammonium acetate to 6 mmol / L ammonium acetate, and mobile phase B was acetonitrile. The gradient elution program was: 0 min → 5.0 min, 5% A; 5 min → 5.5 min, 5% A → 30% A; 5.5 min → 8.0 min, 30% A; 8 min → 8.5 min, 30% A → 5% A; 8.5 min → 12 min, 5% A.

[0013] The mass spectrometer employs atmospheric pressure chemical ionization negative ion mode.

[0014] A second aspect of the present invention provides the application of the above-described detection method in the quality control of coated metal can packaging or its contents, specifically the beverage.

[0015] In this invention, by passing the sample of the coated metal can-packaged beverage to be tested through a polyamide solid-phase extraction column during sample pretreatment, and by selecting a specific chromatographic column and gradient elution program during ultra-high performance liquid chromatography-mass spectrometry detection, while employing atmospheric pressure chemical ionization negative ion mode, and in conjunction with other chromatographic and mass spectrometric conditions, sorbitol and mannitol in the sample of the coated metal can-packaged beverage to be tested can be well separated under conventional mobile phase conditions without damaging the mass spectrometer, and with minimal matrix effect, achieving highly sensitive detection of sorbitol and mannitol.

[0016] In the preparation of the test solution of the present invention, the beverage sample in the coated metal can is subjected to solid phase extraction by a polyamide solid phase extraction column, which can effectively remove the pigments in the beverage sample (after passing through the polyamide solid phase extraction column, most of the original colored beverages are colorless, becoming colorless (cola, orange juice) or very pale yellow (beer)). Moreover, the polyamide solid phase extraction column has virtually no adsorption of sorbitol and mannitol in the beverage sample, and will not affect the recovery rate of sorbitol and mannitol in the beverage sample.

[0017] The method for detecting sorbitol and mannitol in coated metal can-packaged beverages of the present invention features simple pretreatment, high accuracy, and low detection limit. It provides excellent technical support for quality control, safety monitoring, and safety supervision of food, food contact coated metal materials and products, and has good economic and social benefits. Attached Figure Description

[0018] Figure 1 This is the extracted ion chromatogram of sorbitol and mannitol in the standard working solution of Example 1 of the present invention.

[0019] Figure 2 This is the extracted ion chromatogram of sorbitol and mannitol in the beer sample of Example 3 of the present invention.

[0020] Figure 3 This is the extracted ion chromatogram of sorbitol and mannitol when detected using a PEI column in Comparative Example 2 of the present invention.

[0021] Figure 4 The working curves of sorbitol and mannitol in APCI+ ion mode in Comparative Example 4 of this invention are shown.

[0022] Figure 5This invention illustrates the effect of different spray pressures on the compound response in Comparative Example 5.

[0023] Figure 6 This invention illustrates the effect of different curtain gas pressures on the compound response in Comparative Example 5.

[0024] Figure 7 This invention illustrates the effect of different ion source temperatures on the compound response in Comparative Example 5.

[0025] Figure 8 This invention illustrates the effect of different spray currents on the compound response in Comparative Example 5.

[0026] Figure 9 This invention illustrates the effect of different declustering voltages on the compound response in Comparative Example 5.

[0027] Figure 10 This is the extracted ion chromatogram of the cola spiked sample detected using different daughter ions in Comparative Example 5 of this invention. Detailed Implementation

[0028] To facilitate understanding of the present invention, a more comprehensive description will be provided below. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the present invention.

[0029] Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. The term "and / or" as used in this invention includes any and all combinations of one or more of the associated listed items.

[0030] Unless otherwise specified, experimental methods in the following examples are generally performed under standard conditions or as recommended by the manufacturer. All commonly used chemical reagents used in the examples are commercially available products.

[0031] In some embodiments of the present invention, a method for detecting sorbitol and mannitol in coated metal can packaged beverages is disclosed, comprising the following steps:

[0032] (1) Transfer the beverage sample in the coated metal can to be tested to a polyamide solid phase extraction column, add water for elution, and collect the eluent; dilute with water and filter through a membrane to obtain the test solution.

[0033] (2) The test solution was detected by ultra-high performance liquid chromatography-mass spectrometry;

[0034] The ultra-high performance liquid chromatography used a hydrophilic-diol column. Mobile phase A was 4 mmol / L ammonium acetate to 6 mmol / L ammonium acetate, and mobile phase B was acetonitrile. The gradient elution program was: 0 min → 5.0 min, 5% A; 5 min → 5.5 min, 5% A → 30% A; 5.5 min → 8.0 min, 30% A; 8 min → 8.5 min, 30% A → 5% A; 8.5 min → 12 min, 5% A.

[0035] The mass spectrometer employs atmospheric pressure chemical ionization negative ion mode.

[0036] In some embodiments, the polyamide solid-phase extraction column in step (1) is a Poly-sery PA polyamide solid-phase extraction column with a specification of 500 mg / 6 mL.

[0037] In some embodiments, the mass spectrometry conditions described in step (2) further include: spray current -3μA to -4μA, declustering voltage -80V to -40V, spray gas pressure 40psi to 50psi, curtain gas pressure 35psi to 45psi, and ion source temperature 300℃ to 400℃.

[0038] In some embodiments, the declustering voltage is -80V to -60V, the spray gas pressure is 40psi to 45psi, the curtain gas pressure is 40psi to 45psi, and the ion source temperature is 300℃ to 350℃.

[0039] In some embodiments, the ultra-high performance liquid chromatography conditions in step (2) further include: injection volume of 0.1 μL to 0.3 μL; column temperature of 28℃ to 32℃; and flow rate of 0.3 mL / min to 0.5 mL / min.

[0040] In some embodiments, the mass spectrometry conditions in step (2) further include: quantitative ion pairs 181.1>101.024 and 181.1>119.035, collision energy -30V to -20V, and collision energy extension 8V to 12V.

[0041] In some embodiments, step (1) is further included before step (1) by performing ultrasonic degassing on the beverage sample in the coated metal can to be tested.

[0042] In some embodiments, the polyamide solid-phase extraction column in step (1) is a pre-activated polyamide solid-phase extraction column, and the activation step includes activation with 9 mL to 11 mL of methanol and 9 mL to 11 mL of water in sequence.

[0043] In some embodiments, the column volume of the coated metal can packaged beverage sample to be tested in step (1) is 0.9 mL to 1.1 mL, and the volume of the eluting water is 1.8 mL to 2.2 mL.

[0044] In some embodiments, the dilution factor in step (1) is 18 to 22 times.

[0045] In other embodiments of the present invention, the application of the above-described detection method in the quality control of coated metal can packaging or its contents (beverages) is disclosed.

[0046] In some embodiments, the coated metal can is packaged as a non-alcoholic beverage (cola, orange juice) or an alcoholic beverage (such as beer).

[0047] In the following examples, the polyamide solid-phase extraction column used was a Poly-sery PA polyamide solid-phase extraction column from CNW GmbH, Germany, with a specification of 500 mg / 6 mL; the chromatographic column was a ChromCore Hilic Diol 100 mm × 2.1 mm, 3 μm column from Nanoparticle Display; the ultra-high performance liquid chromatography was an Aquity UPLC H-Class Plus from Waters Corporation; and the quadrupole time-of-flight mass spectrometer was an X500B from Sciex Corporation.

[0048] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0049] Example 1: A method for detecting sorbitol and mannitol in beverages packaged in coated metal cans.

[0050] Includes the following steps:

[0051] 1. Preparation of standard working solutions

[0052] ① Standard stock solutions (10 mg / mL): Accurately weigh 100 mg (accurate to 0.01 mg) of D-sorbitol (CAS 50-70-4, Maclean's, 98.0%) and D-mannitol (CAS 69-65-8, Maclean's, 99%) into 10 mL volumetric flasks, dissolve in water, dilute to the mark, shake well, transfer to reagent bottles, and store at -20 °C to obtain separate standard stock solutions of sorbitol and mannitol.

[0053] ② Mixed standard intermediate solution 1 (1 mg / mL): Transfer 1 mL of the individual standard stock solution to a 10 mL volumetric flask, dilute to the mark with water, shake well, transfer to a reagent bottle, and store at -20℃.

[0054] ③ Mixed standard intermediate solution 2 (10mg / L): Transfer 1mL of the separate standard stock solution to a 100mL volumetric flask, dilute to the mark with water, shake well, transfer to a reagent bottle, and store at -20℃.

[0055] ④ Standard working solutions: Accurately transfer 0.20 mL, 0.50 mL, 0.75 mL, 1.00 mL, 2.00 mL, and 3.00 mL of mixed standard intermediate solution 2 into six 10 mL volumetric flasks, respectively. Dilute to the mark with water, shake well, and prepare before use. The corresponding target analyte concentrations in each standard working solution are 0.20 mg / L, 0.50 mg / L, 0.75 mg / L, 1.00 mg / L, 2.00 mg / L, and 3.00 mg / L, respectively.

[0056] 2. Preparation of test solution and blank solution

[0057] Transfer the beverage sample to a wide-mouth reagent bottle and place it in an ultrasonic cleaner for ultrasonic degassing for 15 minutes. Remove the bottle. Transfer 1.00 mL of the ultrasonically degassed sample to a pre-activated polyamide solid-phase extraction column (activated sequentially with 10 mL of methanol and 10 mL of water, a standard procedure in this field). Add 2.00 mL of water for elution, collect the eluent, and vortex to mix. Transfer 0.50 mL of the eluent to a 10 mL graduated tube, dilute to the mark with water, and vortex to mix. Filter approximately 1 mL of the solution through a 0.22 μm aqueous filter membrane into a vial to obtain the test solution.

[0058] The blank test solution was prepared using the same method.

[0059] 3. Detection using ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry

[0060] The standard working solution, blank solution, and test solution were tested separately to obtain raw data.

[0061] ① Liquid chromatography conditions include:

[0062] Chromatographic column: ChromCore Hilic Diol 100mm×2.1mm, 3μm;

[0063] Column temperature: 30℃;

[0064] Injection volume: 0.2 μL;

[0065] Mobile phase A: 5 mmol / L ammonium acetate;

[0066] Mobile phase B: Acetonitrile;

[0067] Flow rate: 0.4 mL / min;

[0068] Gradient elution program: 0 min → 5.0 min, 5% A; 5 min → 5.5 min, 5% A → 30% A; 5.5 min → 8.0 min, 30% A; 8 min → 8.5 min, 30% A → 5% A; 8.5 min → 12 min, 5% A;

[0069] ②Mass spectrometry conditions include (atmospheric pressure chemical ionization source):

[0070] Ion source temperature: 350℃;

[0071] Spray current: -3μA

[0072] aerosol: 40Psi;

[0073] Air curtain gas: 40Psi

[0074] Mass spectrometry scanning method: High-resolution multiple reaction monitoring (MRMHR);

[0075] Precursor ion (m / z): 181.1

[0076] Daughter ion scanning range (m / z): 50-120;

[0077] Impact energy: -25V;

[0078] Collision energy expansion: 10V

[0079] Extracted ions (m / z): 101.024 (quantitative ions), 119.035 (qualitative ions).

[0080] 4. Results Analysis

[0081] Quantitative ion extraction ion chromatography of standard working solutions Figure 1 As shown.

[0082] The standard operating curve, correlation coefficient, linear range, and signal-to-noise ratio are shown in Table 1.

[0083] Table 1 Standard operating curve, correlation coefficient, and linear range

[0084]

[0085] The ratio of the retention time of the analyte peak in the test solution to the retention time of the analyte peak in the standard working solution should have a deviation of within ±5%.

[0086] Based on the peak areas of the chromatographic peaks of the blank test solution and the test solution, the content of sorbitol or mannitol in the test solution is obtained from the standard working curve. Then, the content of sorbitol or mannitol in the test solution is calculated according to formula (1).

[0087]

[0088] In the formula:

[0089] X—The content of the analyte (sorbitol or mannitol) in the test sample, mg / L;

[0090] c1—The content of the analyte in the test solution obtained from the standard working curve, in mg / L;

[0091] c0—The content of the analyte in the blank sample solution obtained from the standard working curve, in mg / L;

[0092] V1—Sample volume, mL (1 mL);

[0093] V2—elution buffer volume, mL (2 mL);

[0094] f—dilution factor, 20.

[0095] Example 2: Methodological Validation of the Detection Method of the Present Invention

[0096] This embodiment verifies the accuracy, precision, and detection limit of the detection method of the present invention.

[0097] Samples of cola, orange juice, and beer packaged in coated metal cans were processed according to the method in Example 1, and different masses of standard substances were added to the samples. Each concentration point was measured in parallel six times. The accuracy and precision of the method were obtained by standard addition recovery rate and relative standard deviation.

[0098] The recoveries of sorbitol and mannitol at different concentrations are shown in Tables 2 and 3.

[0099] Table 2. Sorbitol Spiking Recovery Rate

[0100]

[0101] Table 3 Mannitol Spiking Recovery Rate

[0102]

[0103] As shown in Tables 2 and 3, the recoveries of sorbitol and mannitol ranged from 73.7% to 104%, with RSDs ranging from 2.4% to 6.0%, indicating good accuracy and precision.

[0104] The method detection limit is obtained based on the signal-to-noise ratio of the spiked solution. The method detection limit (S / N≥3) can reach 4 mg / L.

[0105] Example 3: Detection of sorbitol and mannitol content in actual samples

[0106] Using the detection method of Example 1 of this invention, sorbitol and mannitol in coated metal cans of cola, orange juice and beer purchased from supermarkets were tested.

[0107] The results are shown in Table 4.

[0108] Table 4. Sorbitol content in beverages packaged in coated metal cans (n=6)

[0109]

[0110] Table 5. Mannitol content in beverages packaged in coated metal cans (n=6)

[0111]

[0112] The results in Tables 4 and 5 show that the purchased coated metal cans of cola and orange juice did not contain sorbitol and mannitol, while the purchased coated metal cans of beer did contain sorbitol and mannitol. Quantitative ion extraction chromatography (QIPC) of the beer samples was also performed. Figure 2 As shown.

[0113] Comparative Example 1

[0114] This comparative example compares the adsorption properties of two pretreatment methods on the tested beverages.

[0115] Method 1 (same as Example 1): Transfer the beverage sample in the coated metal can to a wide-mouth reagent bottle, place it in an ultrasonic cleaner, and degas it ultrasonically for 15 minutes. Remove the bottle. Transfer 1.00 mL of the ultrasonically degassed sample to a pre-activated polyamide column (activated sequentially with 10 mL of methanol and 10 mL of water, which is a conventional method in the art), add 2.00 mL of water for elution, collect the eluent, and vortex to mix.

[0116] Method 2: Transfer 1.00 mL of beverage sample into a 10 mL centrifuge tube containing 50 mg of coconut shell activated carbon, vortex for 1 min, centrifuge at 4000 rpm, remove the supernatant, add 5 mL of water, soak at 95 °C for 1 hour, filter the soaking solution while it is still hot, and then detect the content of sorbitol and mannitol in the soaking solution.

[0117] Samples such as cola, orange juice, and beer were processed using Method 1. The pigments were largely retained on the column. After processing a 20 mg / L standard working solution using Method 1, subsequent detection was performed according to the method in Example 1. The recoveries of sorbitol and mannitol were approximately 100% and 99%, respectively. This result demonstrates that the polyamide column has virtually no adsorption effect on sorbitol and mannitol.

[0118] After treating the 4 mg / L standard working solution using Method 2, the soaking solution was then tested using the instrumental method described in Example 1. The recoveries of both sorbitol and mannitol were less than 50%. This indicates that coconut shell activated carbon causes irreversible adsorption of sorbitol and mannitol. Therefore, the pretreatment method using coconut shell activated carbon is not suitable for the detection of sorbitol and mannitol.

[0119] Comparative Example 2

[0120] This comparative example demonstrates the effectiveness of three different chromatographic columns in the simultaneous detection of sorbitol and mannitol.

[0121] 1. The preparation method of the test solution is the same as in Example 1.

[0122] 2. Detection using ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry

[0123] The standard working solution (2 mg / L) was detected using three different chromatographic columns: ChromCore Hilic Diol (100 mm × 2.1 mm, 3 μm), Welch Hilicamide (100 mm × 2.1 mm, 3 μm), and HYPERSIL GOLD Hilic PEI (100 mm × 2.1 mm, 1.9 μm). All other conditions were the same as in Example 1.

[0124] The results showed that the Welch Hilic amide column could not separate the two compounds at all. Compared with the ChromCore Hilic Diol column, the HYPERSIL GOLD Hilic PEI column showed better separation of the two compounds. The chromatograms of the standard working solutions are shown below. Figure 3 .

[0125] However, when analyzing actual samples, the matrix effect of the HYPERSIL GOLD Hilic PEI column was very significant. In cola (n=6), the absolute recovery of sorbitol was only about 55%; in orange juice (n=6), the absolute recovery of mannitol was also only about 55%.

[0126] Therefore, neither Welch Hilic amide nor HYPERSIL GOLD Hilic PEI columns are suitable for the simultaneous detection of sorbitol and mannitol.

[0127] Comparative Example 3

[0128] This comparative example demonstrates the effectiveness of two mobile phases, A and B, in simultaneously detecting sorbitol and mannitol.

[0129] 1. The preparation method of the test solution is the same as in Example 1.

[0130] 2. Detection using ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry

[0131] The standard working solution (2 mg / L) was tested using two different mobile phases A (5 mmol / ammonium acetate, methanol + water = 1 + 9), and all other conditions were the same as in Example 1.

[0132] The results showed that the separation effects of the two compounds were similar under both mobile phases, but the compound response was twice as high when 5 mmol / ammonium acetate was used as mobile phase A, compared to methanol + water = 1 + 9 as mobile phase A.

[0133] Comparative Example 4

[0134] This comparative study examines the effects of different ion sources and ionization methods on the simultaneous detection of sorbitol and mannitol.

[0135] 1. The preparation method of the test solution is the same as in Example 1.

[0136] 2. Detection using ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry

[0137] Four different ion sources and ionization methods (electrospray ionization negative ion mode (ESI-), electrospray ionization negative ion mode (ESI+), atmospheric pressure chemical ionization negative ion mode (APCI-), and atmospheric pressure chemical ionization positive ion mode (APCI+)) were used to detect cola samples (n=6), and all other conditions were the same as in Example 1.

[0138] The results showed that mannitol in the cola sample had a matrix effect of 41% in ESI+ and 61% in ESI-. APCI+, due to the presence of source fragmentation, exhibited a quadratic response curve. Figure 4 ).

[0139] Therefore, only APCI- is suitable as an ionization method for the simultaneous detection of mannitol and sorbitol.

[0140] Comparative Example 5

[0141] This comparative study demonstrates the effectiveness of different mass spectrometry parameters in the simultaneous detection of sorbitol and mannitol.

[0142] 1. Spray air pressure

[0143] (1) The preparation method of the test solution is the same as in Example 1.

[0144] (2) Detection by ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry

[0145] The standard working solution (2 mg / L) was tested using three different spray pressures (40 Psi, 50 Psi, and 60 Psi), while all other conditions were the same as in Example 1.

[0146] See results Figure 5 The results showed that the compound's response decreased significantly at a spray pressure of 60 Psi, while the compound's response was similar at spray pressures of 40 Psi and 50 Psi.

[0147] 2. Air curtain pressure

[0148] (1) The preparation method of the test solution is the same as in Example 1.

[0149] (2) Detection by ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry

[0150] The standard working solution (2 mg / L) was tested using four different air curtain pressures (30 Psi, 35 Psi, 40 Psi, and 45 Psi), with all other conditions being the same as in Example 1.

[0151] See results Figure 6 The results showed that the compound's response was significantly higher when the curtain gas was in the range of 35 Psi to 45 Psi than when the curtain gas was in the range of 30 Psi.

[0152] 3. Ion source temperature

[0153] (1) The preparation method of the test solution is the same as in Example 1.

[0154] (2) Detection by ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry

[0155] The standard working solution (2 mg / L) was tested using three different ion source temperatures (400℃, 350℃, and 300℃), while all other conditions were the same as in Example 1.

[0156] See results Figure 7 The results showed that the compound had a high response at all three ion source temperatures, with the highest response at 350 °C.

[0157] 4. Spray current

[0158] (1) The preparation method of the test solution is the same as in Example 1.

[0159] (2) Detection by ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry

[0160] The standard working solution (2 mg / L) was tested using three different spray currents (-2 μA, -3 μA, and -4 μA), while all other conditions were the same as in Example 1.

[0161] See results Figure 8 The results showed that the compound response was significantly improved when the spray flow rate was -3 μA and -4 μA. Although the compound response was highest at -4 μA, the smaller spray current was beneficial to the long-term stability of the instrument operation. Therefore, the optimal spray flow rate was -3 μA.

[0162] 5. Declustering voltage

[0163] (1) The preparation method of the test solution is the same as in Example 1.

[0164] (2) Detection by ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry

[0165] The standard working solution (2 mg / L) was tested using three different declustering voltages (-80V, -60V, and -40V), while all other conditions were the same as in Example 1.

[0166] See results Figure 9 The results showed that the compound had the highest response when the declustering voltage was -60V.

[0167] 6. Monitoring ion pairs

[0168] Both sorbitol and mannitol can produce daughter ions with parent ions of 59.01, 71.01, 73.03, 85.03, 89.02, 101.02, 113.02, and 119.04. According to the SN / T 3142-2012 standard and some existing literature, the commonly used ion pairs for mannitol and sorbitol are 181>89, 181>71, and 181>101. The inventors used 71.01 and 101.02 as daughter ions to detect spiked cola samples (20 mg / L) (the test solution and other detection conditions were the same as in Example 1). The extracted ion chromatogram is shown below. Figure 10 ,Depend on Figure 10 It is evident that the 71.01 ion exhibits significantly more interference peaks and is therefore unsuitable as a ion for detecting sorbitol and mannitol.

[0169] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0170] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for detecting sorbitol and mannitol in beverages packaged in coated metal cans, characterized in that, Includes the following steps: (1) Transfer the beverage sample in the coated metal can to be tested to a polyamide solid phase extraction column, add water for elution, and collect the eluent; dilute with water and filter through a membrane to obtain the test solution; the polyamide solid phase extraction column is a Poly-sery PA polyamide solid phase extraction column. (2) The test solution was detected by ultra-high performance liquid chromatography-mass spectrometry; The ultra-high performance liquid chromatography used a Hilic-Diol column, with mobile phase A being 4 mmol / L ammonium acetate to 6 mmol / L ammonium acetate, and mobile phase B being acetonitrile. The gradient elution program was: 0 min → 5.0 min, 5% A; 5 min → 5.5 min, 5% A → 30% A; 5.5 min → 8.0 min, 30% A; 8 min → 8.5 min, 30% A → 5% A. 8.5 min → 12 min, 5% A; The mass spectrometer employs atmospheric pressure chemical ionization negative ion mode. The mass spectrometry conditions also include: spray current -3 µA to -4 µA, declustering voltage -80V to -40V, spray gas pressure 40 psi to 50 psi, curtain gas pressure 35 psi to 45 psi, ion source temperature 300℃ to 400℃; quantitative ion pairs 181.1>101.024 and 181.1>119.035, collision energy -30 V to -20 V, and collision energy spread 8 V to 12 V.

2. The method for detecting sorbitol and mannitol in coated metal can-packaged beverages according to claim 1, characterized in that, The de-clustering voltage is -80V to -60V, the spray gas pressure is 40 psi to 45 psi, the curtain gas pressure is 40 psi to 45 psi, and the ion source temperature is 300℃ to 350℃.

3. The method for detecting sorbitol and mannitol in coated metal can-packaged beverages according to claim 1, characterized in that, The ultra-high performance liquid chromatography conditions described in step (2) also include: injection volume of 0.1 µL to 0.3 µL; column temperature of 28℃ to 32℃; and flow rate of 0.3 mL / min to 0.5 mL / min.

4. The method for detecting sorbitol and mannitol in coated metal can-packaged beverages according to any one of claims 1 to 3, characterized in that, The process includes an ultrasonic degassing treatment of the beverage sample in the coated metal can before step (1).

5. The method for detecting sorbitol and mannitol in coated metal can-packaged beverages according to any one of claims 1 to 3, characterized in that, The polyamide solid phase extraction column mentioned in step (1) is a pre-activated polyamide solid phase extraction column. The activation step includes activation with 9 mL to 11 mL of methanol and 9 mL to 11 mL of water in sequence.

6. The method for detecting sorbitol and mannitol in coated metal can-packaged beverages according to any one of claims 1 to 3, characterized in that, In step (1), the volume of the coated metal can packaged beverage sample to be tested on the column is 0.9 mL to 1.1 mL, the volume of the eluting water is 1.8 mL to 2.2 mL, and the dilution factor is 18 to 22 times.

7. The application of the detection method according to any one of claims 1 to 6 in the quality control of coated metal can packaging or the beverage contained therein.

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