Objective To study the determination of total phosphorus in carbon compound lithium iron phosphate by direct carbon removal gravimetric method. Methods After the sample was decomposed by perchloric acid and the carbon in the sample was removed at the same time, the yellow quinoline phosphomolybdate was precipitated by the reaction of orthophosphoric acid with the precipitant quinomolymonone in the acidic medium. The phosphorus content could be obtained by filtration, washing, drying and weighing. Results The carbon removal by perchloric acid was complete and clear, and the steps of filter and carbon removal were reduced. The precision and accuracy tests of the method were carried out by optimizing the conditions. The relative standard deviation (RSD) of the method was less than 0.2%, and the recovery rate of standard addition was 98.4% ~ 101.1%. The biggest advantage of this method is that carbon is directly removed in the digestion process, eliminating the influence of carbon encapsulation on phosphorus determination, no need to filter carbon removal, shorten the operation process, short analysis time, high content of phosphorus is determined by classical gravimetric method, which has high precision and accuracy, and can provide rapid and accurate results for production. Conclusion This method is suitable for the rapid and accurate determination of total phosphorus in carbon complex lithium iron phosphate.

With the increasingly serious environmental pollution, food may be affected by various new pollutants, such as microplastics and heavy metals. Therefore, it is necessary to continuously study the detection methods of new pollutants to ensure the overall safety of food. This article makes a deep thinking and innovative discussion on food testing work under the background of food safety.

Objective To improve temperature check technology for resistance to thermal shock of ceramic cookware products and to enhance the work efficiency. Methods By using different temperature testing tools of infrared thermometer and compact spot finder infrared camera to test resistance to thermal shock of samples, and the experimental steps and results were compared and analyzed. Results For infrared thermometer, manual handheld operation is required to detect the bottom temperature of a sample, which has low safety and poor detection repeatability; For the compact spot finder infrared camera, it can be connected to a computer for automation to detect temperature of sample, which can achieve the temperature visualization, easy to operate, more safety and reliable. Conclusion The experimental data shows that the compact spot finder infrared camera provides safe and reliable technical support for the detection of resistance to thermal shock of ceramic cookware. This experiment provides technical guidance for improving the quality of ceramic cookware products.

To explore the limitations of the low air pressure test methods for electronic and electrical products, and to propose ways to optimize and improve the test methods. To analyze the influence of low air pressure environment on the performance, reliability and life of electronic products, and to summarize the important role of low air pressure test in the reliability assessment of electronic products. From the four aspects of test equipment, test conditions, test point arrangement and data processing methods, suggestions are made to improve the low air pressure test methods. For the test equipment, it is proposed to adopt new vacuum pumps, high vacuum chamber materials, optimize the sealing structure, and introduce precise temperature control algorithms; for the test conditions, it is proposed to reasonably select the air pressure value and rate of change according to the product environment, match the temperature conditions, and take into account the test efficiency and failure incentives; for the test point layout, it is proposed to focus on the key devices and weak structures, and adopt suitable wiring materials and direction design; for the data processing method, it is proposed to improve the low air pressure test method. For the data processing method, it is suggested to introduce new methods such as machine learning and signal processing to explore the failure law and performance trend, and focus on the visualization of the analysis results. Strengthening the research on low air pressure test methods is of great significance to enhance the reliability of electronic products and promote their application in rail transportation, aerospace and other fields, which requires the joint efforts of industry, academia and research institutes.

Objective To establish a rapid method for the determination of neutral degreaser concentration by quantitative acid addition and nonlinear fitting, and to solve the problem of titration method and weighing method lack of accuracy and detection efficiency. Methods Prepare the working curve solutions of different concentrations by using the degreaser original solution, and measure the $\mathrm{{pH}}$ value after adding a quantitative amount of acid.The relationship function between the $\mathrm{{pH}}$ value and the concentration of degreaser is obtained by non-linear fitting, and then the concentration in the production sites degreasing solution is calculated by the function.Explore the amount of acid added, curve fitting method, and fitting order, and determine the optimal experimental conditions. Results The method was applied to the rapid determination of neutral degreaser concentration, with a relative standard deviation (RSD) of 0.85% to 1.17% and a recovery rate between 98.52% to 103.34%. Conclusion The new method proposed in this study is accurate, reliable, simple and rapid.And overcomes the shortcomings of traditional titration and gravimetric methods, it can effectively guide the application of neutral degreaser and improve the surface quality of metal materials.

This study aims to explore the specific application of non-destructive testing technology in quality control of pouring molds, in order to improve the accuracy and reliability of mold manufacturing. Mainly using ultrasonic testing technology to detect mold materials, in order to accurately identify defect locations and evaluate material stress distribution. At the same time, infrared thermal imaging technology is used to monitor the temperature distribution and processing parameters of the mold surface, in order to evaluate the surface quality. The research results indicate that non-destructive testing technology has significant advantages in quality control of pouring molds and can effectively improve the level of quality control. I hope that through the research in this article, we can effectively improve the technological level of the mold manufacturing industry and promote its development.

Objective Therefore, the purpose of this study is to verify and optimize the microbial contamination control strategies during the production of sterile injections to ensure product safety and improve production quality. Methods A randomized trial design was conducted between January 2022 and December 2023, a traditional control strategy between January 2022 and December 2022, and a post-optimized strategy between January 2023 and December 2023. By comparing the microbial pollution under different strategies, combining with the production environment monitoring, process process analysis and operator behavior code assessment, the effectiveness of the control strategy is comprehensively evaluated, and the strategy is optimized. Results The study found that the optimized strategy greatly reduced the risk of microbial contamination and improved production efficiency and product quality. Conclusion The validation and optimized microbial contamination control strategy has significant results in the production of sterile injection, which provides a strong guarantee to ensure the sterility and safety of the injection products. In the future, the production process will be continuously monitored, and the control strategy will be dynamically adjusted according to the actual situation to meet the changing production environment and regulatory requirements.

Food re-inspection refers to food production and operation of food safety supervision and sampling inspection conclusions have objections and in accordance with the law to the market supervision and management department to submit an application for re-inspection, market supervision and management department commissioned the re-inspection of the re-inspection of the backup samples for review and inspection of the behaviour.Re-inspection is an important way for food producers and operators to safeguard their legitimate rights and interests, an important link for market supervision departments to ensure the high quality of food safety supervision work, and an important measure to ensure the relatively fair and stable operation of the market. Because the retest conclusion serves as the final conclusion Therefore, the professionalism of the re-inspection institution is particularly important in the re-inspection work. Based on the perspective of the re-inspection institution, this paper analyzes the risk points of the food re-inspection acceptance work (i. e., contract review), so that the re-inspection institution can avoid potential risks and lay a solid foundation for the smooth progress of the whole re-inspection work.

Food inspection and testing institutions need to obtain corresponding qualification recognition in order to provide verifiable data results to society. Familiarity with the CMA qualification recognition and review process is a condition for the normal operation of food inspection and testing institutions. This article is based on the requirements outlined in RB/T214-2017, RB/T215-2017, and related norms and testing standards. Using the example of the on-site assessment of the CMA qualification extension for the food testing laboratory at the Zhenjiang Food and Drug Supervision Inspection Center, this article conducts an analysis of non-conformities and proposes targeted improvements. Additionally, it summarizes some experiences and reflections in areas such as personnel, instrumentation, system documentation, environmental facilities, and method validation. These insights are intended to serve as a reference for relevant personnel and laboratories in their pursuit of normal operations and conducting CMA qualification assessment reviews.

Objective To evaluate the uncertainty evaluation for the determination of imidacloprid in Caidian lotus root by ultra performance liquid chromatography-tandem quadrupole mass spectrometry. Methods According to GB/T 20769 - 2008 Determination of 450 pesticides and related chemicals residues in fruits and vegetables-Liquid chromatography-tandem mass spectrometry, the content of imidacloprid in Caidian lotus root was determined and the mathematical model was built. According to the provisions of JJF 1135-2005 Evaluation of measurement uncertainty in chemical analysis and JJF 10591-2012 Technical specification for evaluation and representation of measurement uncertainty, the uncertainty was quantified by scientific analysis, and the extended uncertainty of imidacloprid content in Caidian lotus root　was finally calculated. Results When the residue imidacloprid in Caidian　lotus root was ${0.322}\mathrm{{mg}}/\mathrm{{kg}}$ , the　relative standard synthetic uncertainty was 0.08689 and the expanded　uncertainty was ${0.0560}\mathrm{{mg}}/\mathrm{{kg}}$ . The　determination results were　 $\left({{0.322}\pm {0.0560}}\right)\mathrm{{mg}}/\mathrm{{kg}},P ={95}\%, k = 2$ . Conclusion The main sources of uncertainty in　the determination of imidacloprid in Caidian lotus root by ultra　performance liquid chromatography-tandem quadrupole mass spectrometry　are the preparation of standard solution, sample pretreatment and　measurement process of the measuring instrument.