Objective A method based on performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) has been developed for the determination of salbutamol in aquatic products and their products. Methods The analyte was enzymatic hydrolyzed in ${\mathrm{{NH}}}_{4}\mathrm{{AC}}$ solution overnight at ${37}^{\circ }\mathrm{C}$ , and extracted by ethyl acetate-isopropanol $\left({1 :1,\mathrm{v}/\mathrm{v}}\right)$ . The extract was cleaned up by QuEChERS method. Quantification was achieved by HPLC-MS/MS with multiple reaction monitoring (MRM) using internal standard method. Results The limit of quantification of salbutamol was ${0.5\mu }\mathrm{g}/\mathrm{{kg}}$ . The average recoveries at three spiked levels of 0.5,1.0 and ${5.0\mu }\mathrm{g}/\mathrm{{kg}}$ ranged from 87.8% to 110.7% with the relative standard deviations of ${2.7}\%\sim {9.6}\%\left({\mathrm{n}=6}\right)$ . Conclusion The method has the advantages of simple pretreatment steps and its sensitivity, precision, and recoveries all meet the requirements of residue detection regulations, accurately solving the problem of lack of relevant technical support for monitoring salbutamol residues in aquatic products and their products.

Food safety issues not only involve the vital interests of the masses, but also related to the harmony and stability of the society and the long-term peace and stability of the whole country, the food industry is duty-bound responsibility and obligation to do a good job in food inspection and testing and control the quality of food. Food safety inspection and testing is a key link to ensure food safety. The authority of food safety inspection and testing institutions depends on its scientific and efficient technical management and service system, the establishment of food safety inspection and testing sharing platform, and the application of a series of new generation information technologies such as big data, cloud computing, and the Internet of Things to food safety control. Make full use of and optimize the allocation of these social resources, and integrate advanced management concepts to promote the standardization of food safety laboratory management processes, which can effectively improve the efficiency and quality of testing work, give full play to the technical support and guarantee role of food testing for food safety, and strengthen the ability of the whole society to prevent and control food safety risks.

Objective To study the detection method of 11a-progesterone and 11a-progesterone acetate by gel permeation chromatography and liquid chromatography, and to provide technical support for market supervision and enterprise quality control. Methods Samples are extracted by ethyl acetate; use 1:1 ethyl acetate: hexane as eluent; purify by gel permeation chromatography (GPC) method; collect the eluent for ${12}\sim {20}\mathrm{\;{min}}$ ; obtain the purified solution from eluent by rotary evaporation; wait for the determination of liquid chromatography. Use 45:55 acetonitrile: water as mobile phase; use C18 $\left({{250}\times {4.6}\mathrm{\;{mm}}}\right)$ chromatographic column for separation; use photo diode array detector for the determination of 11a-progesterone and 11a-progesterone acetate at ${245}\mathrm{\;{nm}}$ . Results The linear correlation coefficient of this method is above 0.995, the recovery rate is ${90.0}\%\sim {102.6}\%$ and 85.1 $\sim {102.7}\%$ , the relative standard deviation (RSD) is ${0.7}\%\sim {2.5}\%$ and ${0.1}\%\sim {8.7}\%$ , the limit of detection is ${0.3}\mathrm{{mg}}/\mathrm{{kg}}$ and 0.6 $\mathrm{{mg}}/\mathrm{{kg}}$ , and the limit of quantification is ${1.0}\mathrm{{mg}}/\mathrm{{kg}}$ and ${2.0}\mathrm{{mg}}/\mathrm{{kg}}$. Conclusion The method is simple, reliable and accurate, and can be used for the determination of 11a-progesterone acetate and 11a-progesterone acetate in cosmetics.

Objective To evaluate the risk of pesticide residues in cucurbit vegetables in Guizhou Qiandongnan Prefecture. Methods LC-MS and GC-MS was used for determination of residues of the level of 50 pesticide residues in cucurbit vegetable samples collected randomly from Guizhou Qiandongnan Prefecture. Results It showed that Pesticide residues were detected in 15 samples of 100 cucurbit vegetables, 8 pesticides were detected, 20 times in total, The average value of food safety index in cucurbit vegetables related to pesticide residues did not exceed the national maximum residue limit in Guizhou Qiandongnan Prefecture. Conclusion Our findings suggest that the potential hazard level of pesticide residues in cucurbit vegetables in Guizhou Qiandongnan Prefecture is acceotable.

Objective This study aims to accurately quantify two key components in Baijiu (Chinese liquor) production and quality control: acetic acid and hexanoic acid. Methods A direct injection-gas chromatography (GC) technique was used for the rapid and precise simultaneous determination of acetic acid and hexanoic acid in Baijiu. Results Using this method, the detection limit for acetic acid reached 0.012 g/L and for hexanoic acid, 0.0050 g/L. All correlation coefficients exceeded 0.999. The relative standard deviations (RSD) were 0.32% for acetic acid and 0.33% for hexanoic acid, with spiked recovery rates of 96.15% for acetic acid and 96.69% for hexanoic acid, respectively. Conclusion The new detection method proposed in this study not only overcomes the limitations of traditional detection methods and gas chromatography in many aspects but also demonstrates high efficiency, sensitivity, and excellent selectivity. This method has significant practical implications for improving the production process of Baijiu, ensuring the consistency of product flavor, and safety.

Objective To study the content level of vanillin in rice and the changes of vanillin in paddy rice processing. Methods Ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was used to determine the contents of vanillin, methyl vanillin and ethyl vanillin in 209 batches of rice from different origins; at the same time, 16 batches of rice were hulled, milled or finished, and the rice and its processed products (brown rice, standard rice or polished rice) were tested. Results Methyl vanillin and ethyl vanillin were not detected in all rice, paddy and their processed products; vanillin was all detected in 209 batches of rice, and the content values were close to the normal distribution, mainly concentrated in ${100}\sim {222\mu}\mathrm{g}/\mathrm{{kg}}$ ; vanillin was detected in rice and its processed products (brown rice, standard rice or polished rice), and the content decreases with the processing accuracy. Conclusion The possibility of naturally occurring vanillin in rice, and the source is probably rice hull; the detection of vanillin in rice is not always illegal addition, the content level of vanillin in rice and paddy rice should be continuously studied and scientifically analyzed to provide scientific evidence for the market supervision department formulating reasonably the risk reference value of rice.

Objective To separate and identify the miscellaneous bacteria in sterilized lactic acid bacteria beverages provided by an enterprise. Methods The miscellaneous bacteria of lactic acid bacteria beverages were isolated and purified using a variety of medias. The isolated strains were identified at the genus and species levels by analysis of ${16}\mathrm{\;S}$ rRNA sequence and matrix-assisted laser desorption/ionization time of flight mass spectrometry. Results A total of 16 strains were isolated, Among them, 5 strains of Acetobacter, 2 strains of Gluconobacter japonicus, 1 strain of Gluconacetobacter liquefaciens, 1 strain of Kocuria palustris, 1 strain of Streptomyces hydrogenans, 1 strain of Staphylocaccus saprophyticus, 1 strain of Bacillus sp, 1 strain of Novosphingobium aromaticivorans, 1 strain of Brevundimonas vesicularis, 2 strains of Yeast, most of which (n=8, 50%)were identified as Acetobacteraceae. Conclusion Acetobacter, Bacillus, Staphylococcus, Brevundimonas vesicularis, mold, Yeast and other microorganisms were isolated from the bactericidal lactobacillus beverage, most of which belongs to Acetobacteraceae.

Objective To explore and analyze the blood physiological and biochemical indicators of SPF grade SD rats of different ages and genders. Method 80 SPF grade SD rats were studied and randomly divided into four experimental groups at 4, 12, 24, and 48 weeks of age. The male to female ratio in each group was 1:1. All SD rats were analyzed for their blood physiological indicators using the XFA6030 animal blood cell analyzer; apply the Beckman Coulter AU5800 fully automated biochemical analyzer to analyze its blood biochemical indicators. Result Compared with SD rats aged 12, 24, and 48 weeks, SD rats aged 4 weeks showed significant differences in WBC, RBC, HGB, HCT, MCV, MCH, MCHC, PLT, PCT, BA #, and BA%(P<0.05), and all indicators reached their peak at 24 weeks. Among the gender differences between male and female, SD rats aged 4 weeks showed differences in BA%; 12. There were differences in WBC and RBC between 24 week old SD rats; 24 week old SD rats showed differences in BA%; 48 week old SD rats showed differences in MCH and PCT, and all differences had P values $<{0.05}$ ; Compared with 12,24, and 48 week old SD rats,4-week old SD rats showed significant differences in AST, CHOL, TP, GLU, CRE, ALT, ALP, BUN, and TG (P<0.05). Among the gender differences between male and female, 4-week old SD rats showed significant differences in CRE and ALP; There were differences in AST, CHOL, and BUN among 12 week old SD rats; There were differences in ALP between 12 week old and 24 week old SD rats, and all P values of the differences were<0.05 . Conclusion There are statistical differences in blood physiological and biochemical indicators among SD rats of the same gender but different age groups. Similarly, there are also differences in blood physiological and biochemical indicators among SD rats of the same age group but different genders.

Objective Due to the poor application effect of current technology in groundwater pollution source water quality monitoring, the recovery rate of pollutants is low, and the RSD is relatively high, aiming at the defects of linear method, the application of ion chromatography technology in groundwater pollution source water quality monitoring is proposed. Methods An automatic sampling device is used to collect water samples upstream of groundwater pollution sources and filter them. By diluting the standard solution of each pollutant, preparing the standard working solution, centrifuging the water sample with the centrifuge, testing the water sample with the ion chromatograph, identifying the pollutants according to the standard working curve and generating the corresponding ion chromatogram, calculating the mass concentration according to the ion content of the pollutant, so as to complete the water quality monitoring of groundwater pollution sources based on the ion chromatographic technology. Results The recovery rate of pollutants is above 90% and the RSD value is lower than 0.1, the application effect of this technology is relatively good. Conclusion The technique has good adaptability and reliability, can be used for water quality monitoring.

With the outbreak of the novel coronavirus in 2020, the demand and production of medical masks have shown a spurt of growth worldwide. In order to ensure the quality and safety of masks, countries around the world generally formulate testing standards for medical masks. This paper mainly compares and analyzes the detection standards of medical masks at home and abroad, and puts forward suggestions for the quality assurance and standard formulation of medical masks in China, which is of great significance to the field of public health.