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 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 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.

With the deepening of double first-class"construction in Chinese universities, the introduction of a large number of scientific research talents, the rapid expansion of scientific research laboratories, the laboratories of science and technology departments are facing the dilemma of limited space and unreasonable layout, at the same time, safety check tasks at all levels are continuously detailed, quantified and standardized. In view of the lack of professional safety inspection personnel, heavy safety inspection tasks, hidden danger rectification is not in place and other problems, this paper puts forward solutions at the college level. This paper explores how to optimize the existing safety inspection system at the college level, and systematically and professionally carry out special rectification of the safety hazards in the laboratory under its jurisdiction. In practice, explore how to better mobilize resources such as lab safety officers and students so that lab safety becomes a habit that can be cultivated, which in turn promotes lab safety at the college and university levels.

University laboratory is the main place of experimental teaching and scientific research, which plays an important role in universities. The safety management of the laboratory is the guarantee of the efficient operation of the laboratory and the improvement of the level of teaching and research. Meanwhile, the laboratory is also a place where the potential high-risk accidents happened. Aiming at the problem in the laboratory safety management, we have improved the laboratory safety management measures to prevent and reduce the occurrence of laboratory safety accidents. This article mainly proposed the potential safety hazards and improvement strategies for the laboratory management, offering valuable insights for refence.

Objective To establish a rapid, accurate and sensitive gaschromatography-mass spectrometry (GC-MS) method for the detection ofdichloroacetic acid (DCA) and trichloroacetic acid (TCA) in drinkingwater samples, and to evaluate the performance and practical applicationof the method. Methods The samples were pretreated by liquid-liquidextraction derivatization technology and then analyzed by GC-MS. ${50\mu }\mathrm{L}$ and ${100\mu }\mathrm{L}$ of DCA and TCAstandards were prepared into mother solutions with concentrations of ${5\mu }\mathrm{g}/\mathrm{{mL}}$ and ${10\mu }\mathrm{g}/\mathrm{{mL}}$ ,respectively, and then diluted with methanol to form a series ofstandard solutions with concentration gradients for the establishment ofstandard curves. 1,2-Dibromopropane was used as the internal standardsubstance to prepare an internal standard extract of ${166.1\mu }\mathrm{g}/\mathrm{L}$ tocorrect the error in the sample analysis process. The spike recoveryexperiment was carried out on ultrapure water to evaluate the accuracyand precision of the method, and the detection limit of the method wasdetermined by the signal-to-noise ratio (S/N) method. Finally, 103drinking water samples were tested to analyze the contents of DCA andTCA. Results The linear ranges of the standard curves were $1 \sim {20}\mathrm{{\mug}}/\mathrm{{mL}}$ for DCA and $1\sim {40}\mathrm{{\mu g}}/\mathrm{{mL}}$ for TCA, withcorrelation coefficients $\left({r}^{2}\right)$ greater than 0.99,recoveries of 99.4%~114.3%, RSDs less than 3.541%, and detection limitsof ${0.1\mu }\mathrm{g}/\mathrm{L}$ and ${0.2\mu }\mathrm{g}/\mathrm{L}$ for DCA and TCA, respectively. The contents of DCA and TCA in 103drinking water samples were lower than the national standard limits,with average concentrations of ${0.25\mu}\mathrm{g}/\mathrm{L}$ and ${0.48\mu}\mathrm{g}/\mathrm{L}$ , respectively, and the data werestatistically significant $\left({P<{0.05}}\right)$ . Conclusion The GC-MS method has good linearity, accuracy, precision and sensitivity, and can meet the needs of drinking water safety monitoring. The method was applied to 103 drinking water samples, and the results showed that the drinking water quality met the national standards and was not seriously contaminated by DCA and TCA.

In the context of high-quality development in China, some operating methods of the traditional inspection and testing industry can no longer meet the actual testing needs, and the rise and development of digitalization and intelligence will promote the revolutionary transformation of the inspection and testing industry. This paper introduced the iron ore moisture detection and control system, and discussed its application in moisture detection. Firstly, the pain points and risks of the traditional inspection methods of iron ore were analyzed, and the concept and significance of the iron ore moisture detection and control system were introduced. The module composition and operation methods of the iron ore moisture detection and control system were introduced in detail, including the design of hardware equipment, cloud computing and process management and control applications. Finally, examples were demonstrated and analyzed. The advantages and application prospects of iron ore moisture detection and control system in inspection and testing industry were demonstrated. It provides a theoretical basis for the digitization and intellectualization of iron ore moisture detection.

This paper discusses the importance and related requirements of discipline in geological experiment testing, including operation discipline, data discipline, safety discipline, confidentiality discipline and team discipline. It elaborates on how to keep discipline by strengthening discipline awareness, strengthening training and learning, establishing supervision mechanism, setting an example and taking serious accountability measures. It emphasized the key role of strict discipline in ensuring the smooth progress of geological experiment and test work, achieving reliable results and promoting the development of geological undertakings, and called on all personnel engaged in geological experiment and test work to always bear in mind the discipline requirements, work solidly with a high sense of responsibility and mission, and lay a solid foundation for geological scientific research and resource development and utilization.

Objective To analyze the content of heavy metals in water and fish in Huayuan River. Methods Microwave digestion and inductively coupled plasma mass spectrometry (ICP-MS) were used to determine the heavy metal content of common freshwater fish such as Branchfish, Carassius elegans, Siniperca elegans and grass carp in Huayuan River. Results The content of heavy metals (Cu, Zn, As, Pb, Cd, Fe, Mn) in all sections of Huayuan River was lower than the standard limit of Class III water in GB 3838-2002, and the overall water quality was good. The cross section fish Cd and As in the upstream border town are slightly polluted. In the lower reaches of Huayuan River, Pb and As were slightly polluted, while Cd was seriously polluted. The single heavy metal hazard coefficient (THQ) and the composite heavy metal hazard coefficient (TTHQ) of fish in Huayuan River are both less than 1, which indicates that the enrichment of heavy metals in fish in Huayuan River will not cause harm to human consumption. Conclusion The results of this study reflect the influence of water pollution degree on heavy metal enrichment of fish in Huayuan River to some extent, and provide reference and theoretical support for the assessment of ecological security, fish resource diversity and food safety of Huayuan River in this region.