In this paper, the equipment management, personnel training and quality control of the laboratory are comprehensively assessed by adopting quality control methods such as checklist evaluation and traceability management. Taking a food testing laboratory as an example, it quantitatively analyzes its quality management and gives the evaluation and improvement suggestions on equipment management, personnel training and quality control of the laboratory. Meanwhile, in the process of establishing a traceable management system, the management of quality control should also be strengthened to improve the accuracy and reliability of testing. Through the improvement and refinement of the laboratory, it can not only enhance the overall quality level of the testing laboratory, but also contribute to the maintenance of social public safety and health.

Objective: To achieve rapid on-site detection of benzoic acid and sorbic acid, two common preservatives in cosmetics, and improve detection efficiency and on-site detection capabilities. Methods: A portable Raman spectrometer which used silver nanoparticles as the enhancement substrate for surface enhanced Raman spectroscopy (SERS) was used to detect benzoic acid and potassium sorbate in cosmetics. Results: Benzoic acid and sorbic acid had characteristic Raman peaks at ${1157}{\mathrm{\;{cm}}}^{-1}$ and ${871}{\mathrm{\;{cm}}}^{-1}$,respectively. Further research showed that the concentrations of benzoic acid and sorbic acid were linearly correlated with the intensity of their characteristic Raman peaks, making quantitative detection possible. This was confirmed by traditional liquid chromatography, and the quantitative results were consistent. Conclusion: This SERS method has the advantages of simplicity, speed, and efficiency, and is expected to achieve rapid on-site detection of preservatives.

Objective In the present paper, the influences of matrix effect (ME) to the quantification of imidacloprid, thiamethoxam and clothianidin in ginger and banana were evaluated, and especially, the influencing factors and compensating means of matrix effect in LC-MS/MS analysis were proposed. Methods In this research, the matrix effects of three neonicotinoid insecticides in ginger and banana were evaluated by LC-MS/MS analysis after QuEChERS pretreatment. Both matrix-matched calibration curves and solvent calibration curves were established for the assessment of matrix effect. Results The linear regression coefficients of the matrix-matched calibration curves were all above 0.999 and the precision of the measured sample results was better than that of the solvent standard. The recoveries and relative standard deviations of all compounds at matrix-matched calibration curves were 86.7%~103.0% and 2.1%~8.3%, respectively. Conclusion Matrix effects can compromise the precision and accuracy of the analysis results. These results also indicated that matrix effects were mainly affected by matrix concentration, the types and samples of matrices and the overall chemical structure of the pesticide. The linear regression coefficients and precision as well as accuracy were more satisfactory for all the pesticides when matrix-matched standard was used, which reflected an excellent compensating means of matrix effect. This can improve the accuracy of quantitative results, which is feasible in routine testing, and is of great significance for ensuring the quality and safety of ginger and banana products.

Objective To verify whether the laboratory can accurately detect fluoroquinolone residues in aquaculture products according to standard Methods. Methods In this article, according to the Methods of Determination of 17 Sulfonamides and 15 Quinolones Residues in Aquatic Products by Liquid Chromatography-Tandem Mass Spectrometry (Ministry of Agriculture Announcement No. 1077-1-2008) and Laboratory Quality Control Specifications for Food Physical and Chemical Testing (GB/T 27404-2008), the method validation of the determination of 5 fluoroquinolones residues in cultured aquatic products by Liquid Chromatography-Tandem Mass Spectrometry was carried out, including linearity range, method sensitivity, accuracy and precision. Results The results showed that the 5 target compounds had good linear relationships in the range of $0 \sim {100\mu}\mathrm{g}/\mathrm{{kg}}$ , with correlation coefficients above 0.99 . The method sensitivity (detection limit, quantification limit) met the method requirements, the average recovery rate was ${93.0}\%\sim {110}\%$ , and the relative standard deviation was $\leq {15}\%$ , all of which met the method requirements. Conclusion It indicates that the laboratory can correctly apply this method for detection work under the existing detection conditions.

Objective To trace the source of a foodborne disease outbreak caused by consuming smoked meat pancakes contaminated with Salmonella enteritidis. Methods Epidemiological investigations were carried out on 8 patients, samples of relevant environment, food and feces were collected, laboratory tests were carried out according to national standards. After bacteria enhancement, suspicious colonies were selected for biochemical identification, and the six strains of Salmonella detected underwent serum agglutination with standard diagnostic sera, drug sensitivity test and pulsed field gel electrophoresis. Result There were 8 cases of this incident, and out of the 6 samples, 6 strains of Salmonella enteritidis were isolated. The detection rates of Salmonella in the food, environmental samples, and cases feces were all 100%. The drug sensitivity test results showed that all strains were resistant to 6 drugs, and the drug resistance spectrum was CT-CTX - TET - CIP - AMP - AMS. They were sensitive to CHL, SXT, ETP, MEM, CAZ, CZA, TIG, AZM, and AMI. The PFGE bands of the 6 strains were consistent, with the homology of ${100}\%$ , and that showed the same clone. Conclusions This incident is a foodborne disease outbreak caused by consuming smoked meat pancakes contaminated with Salmonella enteritidis.

Objective To develop an ultra high performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) to identification of the feeding status of turtle and turtle shell components in different batches of Gejie Dingchuan Pills. Methods This study used the identification method of characteristic peptides of Animal medicine for reference, Enzymatic hydrolysis of different batches of Ge jie Ding chuan Pill samples using trypsin, and Identification by using the ultra high performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). The characteristic ion pairs of Testudinis Carapax et Plastrum and Trionycis Carapax were as detection ion pairs. The positive electrospray ionization and multiple reaction monitoring were adopted. Result: 51 batches of Gejie Ding chuan Pills form 8 companies have all detected turtle shell components, but no other turtle source components have been detected. Conclusion This method is raliable for identification of Testudinis Carapax et Plastrum and Trionycis Carapax form Ge jie Ding chuan Pill.

Objective: This study aims to explore a method for determining the concentration of free amino acids in cell culture media based on ultra performance liquid chromatography (UPLC). Methods Researchers used UPLC technology combined with optimized sample processing Methods to efficiently and accurately determine free amino acids in cell culture medium. Results The research results indicate that the UPLC method can quickly and reliably determine the concentration of free amino acids in cell culture medium, providing an effective means for monitoring and optimizing cell culture in the biopharmaceutical industry. Conclusion Accurate determination of amino acid concentration not only helps to better understand the dynamic changes of key nutrients in cell culture media, but also provides important data support for process optimization in the production process.

Objective A method for simultaneous determination of MBAA, DBAA, DCAA, TCAA and ${\mathrm{{ClO}}}_{2}{}^{- }$ in drinking water was established by ion chromatography. Methods The water samples were determined by ${0.22\mu}\mathrm{m}$ qeuosystem filter membrane with a volume of ${500\mu }\mathrm{L}$ . The samples were rinsed with $\mathrm{{KOH}}$ solution gradient and separated by IonPac AS19 anion column. The column temperature was set at ${30}^{\circ }\mathrm{C}$ , and the current of the inhibitor was ${75}\mathrm{\;{mA}}$ . Results The results showed that the linearity ranges of ${\mathrm{{ClO}}}_{2}{}^{- }$ , MBAA, DBAA, DCAA and TCAA were found in the range of ${10}\sim {1000\mu}\mathrm{g}/\mathrm{L},\mathrm{r}> {0.9990}$ , with detection limits $\left({3\mathrm{\;S}/\mathrm{N}}\right)$ of ${0.32},{0.76},{1.30},{0.69},{1.58\mu}\mathrm{g}/\mathrm{L}$ . The standard recoveries were ${80}\%\sim {110}\%$ and RSD (n=6) of the determined values were all less than 5.0%. Conclusion The method was simple, sensitive, can meet the detection requirements of four kinds of Haloaeetic Acids and Chlorite in drinking water. The method can be used for the determination of kour kinds of haloaeetic acids and chlorite in drinking water.

Objective The aim of this study is to investigate the variation of SERS effect intensity with the distance between probe molecules and the enhanced surface using atomic layer deposition (ALD) technology. Methods The study used ALD technology to deposit two-dimensional materials with different thicknesses on the surface of SERS to block raman probe molecules from the surface, exploring the weakening effect of different interaction distances on the SERS effect of the surface, and studying the changes in raman spectral intensity of probe molecules;the study used a silver-silicon combination as the SERS substrate, and a crystal violet aqueous solution with a concentration of ${10}^{-4}\mathrm{\;{mol}}/\mathrm{L}$ as a raman probe to conduct SERS effect exploration experiments on two-dimensional materials with different thicknesses. Results The final experimental results prove that the liquid SERS spectral intensity at the ${532}\mathrm{\;{nm}}$ laser wavelength generally weakens with the increase in the thickness of the two-dimensional material. Conclusion 5 nm thickness is its limiting distance.

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.