Objective Exploring the effect of nicotinamide concentration on skin melanin transfer and its mechanism of action, to provide a scientific basis for the development and application of related skin care products and beauty technology. Methods The mechanism of nicotinamide inhibiting the formation of melanin was elucidated, and the main influencing factors of the formation of black spots were analyzed, so as to control the formation and transfer of melanin. The researchers then combined a variety of substances, including arbutin, phenylresorcinol, and vitamin C and its derivatives, to study. Results Nicotinamide was able to effectively inhibit the diffusion rate of melanin by blocking the transfer process of melanin particles to epidermal cells. When used in combination with arbutin, phenylethyresorcinol and vitamin C, its inhibitory effect is more obvious. Conclusion Niacinamide and its synergistic effect with other substances can effectively inhibit the transfer and diffusion of melanin, providing a new way for skin whitening. This discovery provides an important reference for the application and development of related skin care products and beauty technologies.

Objective To compare the role of enzyme-linkedimmunosorbent assay and toluidine red unheated serum test in thediagnosis of syphilis. Methods 78 suspected syphilis patients in ourhospital were analyzed from January 1st, 2023 to December 31st, 2023,enzyme linked immunosorbent assay and toluidine red unheated serum testwere performed on all patients, and the testing procedures were strictlyfollowed according to the instructions. Compare the diagnosticsensitivity, specificity, and accuracy of enzyme-linked immunosorbentassay (ELISA) and toluidine red unheated serum test based on the resultsof syphilis Treponema pallidum gelatin particle agglutination test.Results The sensitivity, specificity, and accuracy of the enzyme-linkedimmunosorbent assay were 93.24%, 75%, and 92.31%, respectively. Thesensitivity, specificity, and accuracy of the toluene red unheated serumtest were 82.43%, 50%, and 80.77%, respectively. The toluene redunheated serum test was lower than the enzyme-linked immunosorbentassay, with a difference of $P<{0.05}$ . Conclusion Enzyme linked immunosorbent assay(ELISA) has higher sensitivity and accuracy in syphilis testing comparedto the non heated serum test with toluidine red, and is worthy ofattention and promotion.

Aspirin is a commonly used drug in clinical practice, which is well-known to the public for its precise therapeutic effect and minimal adverse drug reactions. Based on the research results of aspirin content determination methods in recent years, this paper introduces the research progress of titration, ultraviolet and visible spectrophotometry, high performance liquid chromatography, near infrared diffuse reflectance method, etc. in determining aspirin content, providing a reference basis for further developing new detection methods for aspirin.

To avoid major differences in the testing process, help customers correctly understand and use reports, and effectively control risks, according to the relevant requirements of Laboratory Accreditation and Inspection Body and Laboratory Mandatory Approval, combined with practical experience, this paper puts forward 10 aspects that should be agreed in the inspection and testing entrustment agreement, analyzes more than 10 items that should be declared in the inspection and testing report, summarizes the key issues that should be paid attention to, and provides general requirements for the industry to refer to, which has a great practical guiding significance for the standardization of inspection and testing activities.

The purpose of this paper is to discuss the application of Liquid Chromatography-Mass Spectrometry (LC-MS) in drug quality analysis in order to improve the accuracy and efficiency of drug detection. The basic principle, equipment and application of LC-MS in drug quality analysis are reviewed in this paper. LC-MS technology has shown excellent performance in the qualitative, quantitative, fingerprint and pharmacokinetics of drugs, providing an efficient and accurate tool for drug quality analysis, and has a broad application prospect.

Objective To establish a new liquid chromatographic methodfor caffeine content in milk tea, to detect the caffeine content ofinstant milk tea in the region, and to make recommendations on healtheffects. Methods The determination was carried out on a Waters highperformance liquid chromatography Symmetry C18 column $\left({{5\mu}\mathrm{m}\times {150}\mathrm{\;{mm}}\times {4.6}\mathrm{\;{mm}}}\right)$ ,the mobile phase was methanol-water $\left({{30}+ {70}}\right)$ at a flow rateof $1\mathrm{\;{mL}}/\mathrm{{min}}$ ,the detection wavelength of ${272}\mathrm{\;{nm}}$ , and the columntemperature was ${35}^{\circ }\mathrm{C}$ . Results Thecorrelation coefficient was $\mathrm{r}={0.9999}$ over the linear range of 1-30 μg/mL, the recoverieswere 97.2%-99.5%, and the method precision was ${0.54}\%$ . Conclusion The method adoptspotassiun ferrocyanide and zinc acetate precipitation centrifugation,which can rapidly extract the effective components of caffeine in milktea and remove the interference of proteins, shorten the pretreatmenttime, optimize the chromatographic conditions, and accelerate thedetection of caffeine.

In order to solve the problems of significant increase in workload, cumbersome management work, duplication of materials and low review efficiency caused by the increase of open subject application year-by-year, this article elaborates and analyzes the various needs in the open project management process, based on the requirements of the project-oriented management system, and the laboratory open subject management system was constructed based on the requirements of subject management system. The system is developed based on SpringBoot microservice architecture, B/S(Browser/Server) architecture, and Java language development. It can complete project demand reporting, requirements review, requirements selection, project application collection, project application review, project project initiation, mid-term inspection results management, and final inspection, and realize the information management of the whole life cycle of laboratory open projects.

With the development of China’s economy, people’srequirements for water quality are getting higher and higher. In orderto protect water resources, we need to do a good job of water qualitymonitoring, real-time monitoring of water quality indicators, timelyfind the trend of water quality changes, and analysis and prediction.The accurate determination of the permanganate index $\left({\mathrm{{COD}}}_{\mathrm{{Mn}}}\right)$ ,as a key indicator for evaluating the degree of pollution by organicmatter and reductive inorganic matter in water bodies, is of greatsignificance. The purpose of this paper is to discuss the qualitycontrol methods during the determination of permanganate index in waterin order to improve the accuracy and reliability of the results.

Total nitrogen, as a fundamental indicator for water quality monitoring, is an important indicator for measuring the degree of water pollution, self purification status, and eutrophication. It is of great significance for evaluating water quality and protecting the ecological environment. This article explores the main factors affecting the detection process of total nitrogen in water using ultraviolet digestion spectrophotometry. By optimizing the detection process through methods such as sample self influencing factors, digestion process control, and reagent and drug purification, the problem of high experimental blank has been effectively solved, and the reliability and accuracy of the detection have been improved.

Objective By analyzing the original detection results of urine organic acids in Changchun, Jilin Province, this study aims to explore the incidence of genetic metabolic diseases related to urine organic acid detection projects in Changchun, Jilin Province, and analyze the detection data. Methods Gas chromatography-mass spectrometry (GC-MS) was used to analyze the results of the urine organic acid detection project submitted by Jilin Jincheng Medical Co., Ltd. in Changchun, Jilin Province from January 2019 to May 2023. Results there were 83 cases of positive diseases in the initial screening, with a positive rate of 3.93%. Among them, there were 43 cases of methylmalonic acidemia with a positive rate of 51.81%, 10 cases of hyperphenylalaninemia with a positive rate of 12.05%, 6 cases of glutaric acidemia type 1 with a positive rate of 7.23%, 5 cases of Citrin protein deficiency with a positive rate of 6.02%, 5 cases of propionaemia with a positive rate of 6.02%, 4 cases of maple diabetes with a positive rate of 4.82%, and 10 cases of other diseases with a positive rate of 12.05%. Conclusion Organic acid metabolism disease, also known as organic aciduria, is the most common genetic metabolic disease. Urine organic acid screening is an effective method for preventing and treating certain genetic metabolic diseases after birth, among which methylmalonic acidemia is the most common genetic metabolic disease with abnormal organic acid metabolism. In order to improve the survival rate and quality of life of children, people must raise awareness, detect, diagnose and treat them early.