redwineDetection of preservatives and sweeteners

Refer to the national standard（GB/T 23495-2009）Utilizing the all-new high-performance technologyLC500HPLCHigh performance liquid chromatography can provide information on benzoic acid, sorbic acid, acesulfame, and sodium saccharin through practical testingHPLCThe detection plan provides accurate and reliable results with good detection limits, suitable forred wineThe determination of benzoic acid, sorbic acid, acesulfame, and sodium saccharin is for reference only by users.

The following are detailed detection methods for benzoic acid, sorbic acid, acesulfame, and sodium saccharin.

1Instruments and reagents

1.1 instrument

LC-500HPLCHigh performance liquid chromatography，SPD-500UV detector, manual injection valve(7725i)，WK-500Chromatography workstation

Chromatographic column250mm×4.6mm×5μm；

Ultrasonic water bath oscillator;

red winegrinder;

pHCalculation;

Balance: The division value is0.001 mg.

1.2 reagent

Methanol: chromatographically pure.

Ammonium acetate solution: Weigh1.54 gAmmonium acetate, dissolve in water and dilute to1000 mL, through0.45μmMicroporous membrane filtration.

Potassium ferrocyanide solution: Weigh106 gpotassium ferrocyanide[K3Fe(CN)6•3H2O]Add water to1000 mL.

Zinc acetate solution: Weigh220gZinc acetate[Zn(CH3COO)2•2H20]Dissolve in a small amount of water and add30mLIced acetic acid, diluted with water tol000mL.

ammonia water(1+1)Mix ammonia water with water of equal volume.

2 Chromatographic conditions

Chromatographic column:Vertex C18Column,250mm x 4.6 mm，5μm；

Mobile phase: methanol+0.02mol/lAmmonium acetate solution(5:95)；

Current Speed:1 mL／min；

Injection volume:20μL；

detection wavelength230nm.

Note:1-Ansaimi;2-Benzoic acid;3-Sorbic acid;4-Saccharin sodium; Chromatogram of mixed standard solution

3　Preparation of Sample Solution

3.1 Samples containing fat and protein

Weighing the contract10gPlace the left and right samples in a beaker (solid samples should be crushed with a blender), and add about60mlDistilled water, followed by ultrasonic water bath oscillation10Minutes, then transfer to100mlIn the colorimetric tube, rinse the beaker thoroughly with a small amount of water; Join5mlPotassium ferrocyanide solution, shake well, then add5 mLZinc acetate solution, shake well; according toPHMeasure the reading and adjust it with ammonia waterPHApproaching neutrality; Dilute to volume with water100mlScale, shake well, use a triangular bottle,Filter paper, glass rod, funnel filtration; Extract the filtrate approximately1.5mlFilter with a microporous membrane, and the filtrate is to be analyzed on the machine.

3.2 Samples without fat or protein

Weighing the contract10gPlace the left and right samples in a beaker (solid samples should be crushed with a blender), and add about60mlDistilled water, followed by ultrasonic water bath oscillation10Minutes, then transfer to100mlIn the colorimetric tube, rinse the beaker thoroughly with a small amount of water; according toPHMeasure the reading and adjust it with ammonia waterPHApproaching neutrality; Dilute to volume with water100mlScale, shake well, use a triangular bottle,Filter paper, glass rod, funnel filtration; Extract the filtrate approximately1.5mlFilter with a microporous membrane, and the filtrate is to be analyzed on the machine.

4　Result Analysis

4.1 Determination of instrument precision

The concentrations of benzoic acid, sorbic acid, sodium saccharin, and acesulfame are as follows:10.0ug/mlParallel determination7Next time.

watch1Precision measurement results

The analysis results show that the relative standard deviation of peak area for each component is less than1%This indicates that the instrument has good reproducibility under selected conditions and can meet the requirements of analysis and determination.

4.2 Determination of Recovery Rate

The accuracy of the analysis results can be measured by the recovery rate. The closer the recovery rate is, the closer it is100%The closer the measured result is to the true value, the better the accuracy. The relative standard deviation of parallel measurement results can indicate the reproducibility of the method.

Take clear herbal tea and samples for spiked experiments, and add benzoic acid, sorbic acid, sodium saccharin, and acesulfame at concentrations of10.00ug/mlStandard solution, parallel test sample7Next, conduct a recovery rate experiment. The measurement results are shown in the table2.

watch2Determination results and recovery rate of spiked cool tea

From the above table, it can be seen that the recovery rate of the spiked determination of Qingliang tea is: benzoic acid is98.5%-103.4%Sorbic acid is98.3%-103.1%Saccharin sodium is97.5%-104.3%,Ansaimi is98.4%-103.3%The recovery rates of each component are close to each other100%Meet the requirements of daily testing.

7. Configuration of liquid chromatography instrument