Benzoic acid is mainly used in the production of antifungal and disinfectant preservatives, fragrances, and food preservatives. In theory, benzoic acid and its sodium salts have low toxicity and can be excreted through normal metabolism in the human body at reasonable doses. Sorbic acid is another widely used preservative in food with good safety, but excessive use can affect bone development and increase liver and kidney burden.

Saccharin sodium, with a sweetness 200~700 times that of sucrose, is a commonly used artificial sweetener. It is not absorbed in the human body, but excessive intake can reduce the absorption capacity of the small intestine and decrease appetite.

In food production, some enterprises are prone to using the above-mentioned food additives beyond the scope in order to improve product taste and extend shelf life, resulting in substandard products and threatening consumer health. In order to strictly control food quality and safety, this article establishes an ultra-high performance liquid chromatography detection method for benzoic acid, sorbic acid, and sodium saccharin in food based on the standard "GB 5009.28-2016 Determination of Benzoic Acid, Sorbic Acid, and Sodium Saccharin in Food", which can provide reference for the detection of preservatives and sweeteners in food.

EXPEC 5180 Ultra High Performance Liquid Chromatography (equipped with a binary ultra-high pressure infusion pump ULC 580, automatic sampler AS 580, column temperature box CH 582, diode array detector DAD 580, and solvent disk ET 580)

According to the GB 5009.28-2016 National Food Safety Standard for the Determination of Benzoic Acid, Sorbic Acid, and Sodium Saccharin in Foods, the sample was extracted with water, the high-fat sample was defatted with n-hexane, and the high protein sample was precipitated with protein precipitant. After centrifugation, an appropriate amount of supernatant was taken and passed through a 0.22 μ m filter membrane for liquid chromatography determination.

The chromatograms of benzoic acid, sorbic acid, and sodium saccharin obtained using EXPEC 5180 detection are as follows:

Dilute the standard stock solution with water step by step to obtain a series of concentrations of benzoic acid, sorbic acid, and sodium saccharin mixed standard working solutions (0.2 μ g/mL, 0.5 μ g/mL, 1 μ g/mL, 2 μ g/mL, 5 μ g/mL, 10 μ g/mL, and 20 μ g/mL). Inject samples from low to high concentration for analysis. Use the mass concentration of the target substance in the standard series solution as the horizontal axis and its corresponding peak area as the vertical axis to establish a calibration curve, with linear correlation coefficients ≥ 0.9999.

Configure 0.5 μ g/mL standard solution for injection, calculate the quantification limit and detection limit according to S/N=10 and S/N=3:

Prepare mixed standard solutions of benzoic acid, sorbic acid, and sodium saccharin with concentrations of 0.5 μ g/mL, 2 μ g/mL, and 10 μ g/mL, and inject them continuously for 6 injections. Analyze the RSD of retention time and peak area of each group of samples to evaluate instrument precision. The results show that the RSD range of retention time is 0.08~0.37%, and the RSD range of peak area is 0.18~4.59%.

By conducting two concentration spiked recovery experiments on blank samples, the results showed that the spiked recovery rate (n=6) ranged from 89.1% to 101.7%.