In this paper, the application and recent progress of mass spectrometry in pesticide residue detection were systematically reviewed. Firstly, the basic principle, instrument composition, advantages and limitations of mass spectrometry technology are introduced, and its remarkable characteristics of high sensitivity and high resolution are emphasized. Then, the application of conventional detection methods such as GC-MS and LC-MS, as well as new mass spectrometry technologies such as HRMS and LC-MS/MS in pesticide residue detection was discussed in detail, especially the ability of these technologies to detect trace pesticide residues in complex substrates. Next, sample preparation and processing methods, such as QuEChERS, as well as key steps for data analysis and results processing. Finally, the reliability and repeatability of test results were ensured through methodological validation and optimization strategies. The research in this paper not only provides comprehensive technical support for pesticide residue detection, but also lays a foundation for further development in the field of food safety and environmental monitoring. The innovation is the integration of a variety of new mass spectrometry technology application cases, demonstrating its powerful capabilities in multi-component simultaneous analysis and trace detection.

Objective The relationship between fitness and single nucleotide gene polymorphism of Yersinia pestis was investigated. Methods In this paper, the mechanism of GTG in competition between different strains was revealed through continuous in vitro co-incubation competition and in vitro static competition. Results With the increase of passage times, GTG strain quickly became the absolute dominant strain and showed competitive adaptability. Under different stresses (Asp deficiency, weak acid and high salt), GTG and TTG strains showed more remarkable adaptability. In the competitive survival test of macrophages, the ratio of GTG strains to TTG strains did not change significantly. In the intracellular competitive amplification product experiment, mice with GTG: TTG=10: 1, the average dose exceeded the theoretical value during the administration process, resulting in early death of the mice. Conclusion GTG has competitive adaptability among different strains. There was no significant difference between the fitness of GTG and TTG strains in the intracellular competition of macrophages and the competition in mice, but TTG strains showed a fitness advantage in E. coli competition.

Objective To establish a chemiluminescence immunoassay (CLIA) for the detection of serum thyroid function. Methods The clinical data of 121 patients with hyperthyroidism, 101 patients with hypothyroidism and 67 patients with normal thyroid function admitted to Tianjin Medical University General Hospital were retrospectively analyzed from February 2023 to May 2024. The levels of serum thyroid stimulating hormone (TSH), free thyroxine (FT4) and free triiodothyronine (FT3) were examined by CLIA, and then the linear range, precision and accuracy of TSH, FT4 and FT3 monitored by CLIA system were counted. Results The linear correlation coefficient(r)values of TSH, FT4 and FT3 were$\geq {0.990}$, and slope(b)was within 0.95-1.00. The intra-batch and inter-batch precision values of TSH, FT4 and FT3 were less than 1/4TEa (CLIA’88) and 1/3TEa (CLIA’88) respectively. The bias of TSH, FT4 and FT3 were less than 1/2TEa (CLIA’88). The levels of TSH, FT4 and FT3 in patients with hyperthyroidism, hypothyroidism and normal thyroid function detected by CLIA were higher than those detected by RAI (P<0.05). Conclusion CLIA has good accuracy and precision in the detection of three items of serum thyroid function, and provides an important basis for clinical detection of three indexes of serum thyroid function.

Objective To compare the results of high-performance liquid chromatography tandem mass spectrometry (LC-MS/MS) and chemiluminescence immunoassay (CLIA) in the determination of serum estradiol (E2) level. Methods From January 2023 to January 2024, 100 patients who were treated in outpatient department and hospitalized in the hospital were selected as the research subjects. Fresh blood samples were collected from all study subjects on the same day, and serum E2 levels were measured by LC-MS/MS and CLIA respectively. Results Serum E2 level measured by CLIA was significantly higher than that of LC-MS/MS ($P <{0.05}$). Pearson correlation test results showed that LC-MS/MS was significantly correlated with CLIA in measuring serum E2 level$\left({r ={0.866}, P <{0.05}}\right)$. There was a linear correlation between serum E2 level measured by LC-MS/MS and CLIA, and the linear regression equation was manifested as$Y ={1.161X}-{6.574}$ $\left({r ={0.973}, n={100}}\right)$. Bland-Altman analysis revealed that the average difference between LC-MS/MS and CLIA in measuring serum E2 level was${0.078}\mathrm{{nmol}}/\mathrm{L}\left({{95}\%\mathrm{{CI}}:{0.069}\sim {0.086}\mathrm{{nmol}}/\mathrm{L}}\right)$, and the consistency limit range was (-0.011,0.143). There were 5%(5/100) points outside the 95% consistency limit range, and within the 95% consistency limit range, and the maximum difference between LC-MS/MS and CLIA was${0.156}\mathrm{{nmol}}/\mathrm{L}$. The average value of serum E2 level measured by LC-MS/MS and CLIA was${0.152}\mathrm{{nmol}}/\mathrm{L}$, suggesting that the consistency of the two methods was poor. Conclusion Serum E2 level determined by CLIA is higher than that determined by LC-MS/MS. There is a certain correlation between the two methods for the determination of serum E2 level, but the consistency is not good. The determination of serum E2 level by CLIA is more suitable for rapid screening. When accurate clinical diagnosis is needed, it is necessary to apply LC-MS/MS to measure serum E2 level.

ABSTRACT: With the advancement of technology and the improvement of people's living standards, the application of active medical devices in the medical field is becoming increasingly widespread. Among them, ultrasound therapy products have received widespread attention due to their non-invasive and significant therapeutic effects. However, due to the complexity of ultrasound therapy products, research on their detection techniques and standards is particularly important. This article provides an overview of the basic principles and testing methods of ultrasound therapy products, conducts in-depth research on the detection technology and standards of ultrasonic therapy products in active medical devices, analyzes relevant testing standards at home and abroad, compares their advantages and disadvantages, and explores the challenges and development trends of testing technology, in order to provide a reference for the detection and quality control of ultrasonic therapy products and promote the standardization and normalization of the medical device industry.

Objective To establish a gas-mass spectrometry method for determination of epichlorohydrin in Metoprolol succinate tablets. Methods The chromatographic column is HP-1MS. Injection temperature is${220}^{\circ }\mathrm{C}$; The injection method is split injection, and the split ratio is${10}: 1$. The heating procedure is to keep the initial temperature at${50}^{\circ }\mathrm{C}$for$3\mathrm{\;{min}}$, then raise the temperature to${80}^{\circ }\mathrm{C}$at a rate of${20}^{\circ }\mathrm{C}/\mathrm{{min}}$for$5\mathrm{\;{min}}$, and to${280}^{\circ }\mathrm{C}$at a rate of${40}^{\circ }\mathrm{C}/\mathrm{{min}}$for$8\mathrm{\;{min}}$. The sample intake capacity is${1\mu }\mathrm{L}$. The ion source is electron bombardment source (EI), ion source temperature is${230}^{\circ }\mathrm{C}$. Mass spectrometry interface temperature is${260}^{\circ }\mathrm{C}$; the monitoring mode of mass spectrometry is SIM. The mass to charge ratios (m/z) are 49, 57 and 62. Results The linear range of epichlorohydrin concentration is${30}\sim {120}\mathrm{{ng}}/\mathrm{{mL}}\left({r >{0.99}}\right)$. The detection limit is${32.37}\mathrm{{ng}}/\mathrm{{mL}}$. The limit of quantitation is${107.89}\mathrm{{ng}}/\mathrm{{mL}}$. RSD of precision is${1.8}\%\left({n = 6}\right)$. The average recovery is${103.8}\%$with RSD of${2.5}\%\left({n = 6}\right)$. Epichlorohydrin was not detected in 3 batches of Metoprolol succinate tablets. Conclusion The established gas-mass coupling method is simple, practical, accurate and reliable, and can be used for the determination of epichlorohydrin in Metoprolol succinate tablets.

Objective To study the combined value of Sysmex XN-20 (A1) automated hematology analyzer and blood smear. Methods 280 blood samples from June 2023 to June 2024 were selected as research objects, including 105 abnormal blood samples. Automated hematology analyzer test and blood smear test were performed, the test results were observed and analyzed, and the coincidence rate of automated hematology analyzer, blood smear test alone and combined test was calculated. Results Sysmex XN-20 (A1) automated blood cell analyzer + blood smear detected 105 abnormal blood samples, with a positive test rate of 37.50%(105/280); Sysmex XN-20 (A1) automated The blood cell analyzer detected 100 abnormal blood samples, and the test compliance rate was 35.71%(100/280); the compliance rate of Sysmex XN-20 (A1) automated hematology analyzer + blood smear test was significantly higher, but the two There is no significant difference$\left({P ={0.661},{\chi }^{2}= {0.192}}\right)$. Among the 105 abnormal blood samples, neutrophils had the highest proportion of abnormalities in 27 cases; red blood cells had the second highest proportion of abnormalities in 19 cases; lymphocytes had the third highest proportion of abnormalities in 17 cases. Conclusion The combined application of Sysmex XN-20 (A1) automated hematology analyzer and blood smear can significantly promote the improvement of the coincidence rate of blood specimen test.

Against the backdrop of rapid global urbanization and booming construction industry, the demand for various materials in construction projects is showing explosive growth. Whether it is the concrete used to build sturdy foundations, the steel bars that bear the structural strength, or the sand, gravel, and cement used to construct foundations, their roles in the construction blueprint are crucial. They must meet the strictest quality specifications and performance indicators to ensure the stability and durability of the project. However, the fierce competition in the market, the complexity of the supply chain, and the lack of regulatory oversight have made the quality of the building materials market quite delicate. This may not only breed engineering defects and bury safety hazards, but also cause unnecessary loss of valuable resources. This article first analyzes the important role of building material testing in construction engineering, discusses the content of building material testing and the hazards caused by inadequate testing work, and focuses on exploring optimization strategies for building material testing in construction engineering for reference.

Objective To develop a gas chromatography-mass spectrometry solid-phase extractionfor detectingphthalic acid esters (PAEs) in the serum of patients with thyroid cancer. Four PAEs, namely, dimethyl phthalate (DMP), diethyl phthalate (DEP), dibutyl phthalate (DBP), and di (2-ethyl) hexyl phthalate (DEHP), were used in experiments. Methods Samples of PAEs were extracted and enhanced using a solid-phase extraction glass column. The column temperature parameters were as follows: the initial temperature was${60}^{\circ}\mathrm{C}$. The temperature was maintained at${60}^{\circ}\mathrm{C}$for 1 min and then increased by${20}^{\circ}\mathrm{C}/\mathrm{{min}}$to${220}^{\circ}\mathrm{C}$. The temperature was then increased by${5}^{\circ}\mathrm{C}/\mathrm{{min}}$to${290}^{\circ}\mathrm{C}$and maintained at${290}^{\circ}\mathrm{C}$for 2 min. The mass spectrometry conditions were as follows: the ionization mode was electron impact, the source energy was${70}\mathrm{{eV}}$, the ion source temperature was${240}^{\circ}\mathrm{C}$, the quadrupole temperature was${150}^{\circ}\mathrm{C}$, and the scanning mode was selective ion monitoring (SIM). These parameters were qualitatively based on the target compound’s retention time and the mass-to-charge ratio (m/z). Quantitative analysis was conductedusing the standard internal method. Results The standard curve regression equations of DMP, DEP, DBP, and DEHP all had excellent linear relationships with correlation coefficients greater than 0.997. The precision of DMP, DEP, DBP, and DEHP was 2.60%, 4.73%, 5.50% and 5.70%, respectively. The average recoveries were in the average range of${94.5}\%$. The detection rate of DBP, DMP, DEP and DEHP were 100%,31.6%,73.46%, and${100}\%$, respectively. Conclusion The method is suitable for simultaneous detection of PAEs in human serum, with low organic dose, short extraction time, good recovery and reproducibility, and low detection limit.

Objective To establish a specific, reliable and accurate quality control method to improve the quality standard of Anwei Granules. Methods The chromatography system, temperature and humidity of different reagents were investigated by silica gel thin layer chromatography (TLC) to optimize the thin layer identification of Coptidis rhizoma, Radix salviae miltiorrhizae and Linderae Radix. The content of total alkaloids in the preparation was determined by UV-Vis. Results The development system of Coptidis rhizoma was determined to be n-butanol-acetic acid-water (7 : 2.5 : 2), the development system of Radix salviae miltiorrhizae was toluene-trichloromethane-ethyl acetate-methanol-formic acid$\left({2 : 3 : 4 :{0.5}: 2}\right)$, and the development system of Linderae Radix was trichloromethane-ethyl acetate-formic acid$\left({4 : 3 :{0.2}}\right)$. The negative results of the three drugs were not interfered. The total alkaloid content was${4.8328}\mathrm{{mg}}/\mathrm{g}$and RSD% was 1.83% by UV-Vis assay. Conclusion In this study, an effective method for improving the quality standard of Anwei Granules was established, which has the characteristics of good repeatability and strong specificity.