Rapid Detection of Nitrate in Aquatic Products by K-model of Characteristic Absorbance Points
长江中下游地区浅水湖泊生源要素的生物地球化学循环
长江中下游地区浅水湖泊生源要素的生物地球化学循环一、本文概述Overview of this article本文旨在深入探讨长江中下游地区浅水湖泊生源要素的生物地球化学循环。
长江中下游地区作为中国的重要经济和文化中心，其浅水湖泊生态系统对于区域生态环境和经济发展具有至关重要的影响。
本文将对这一区域内浅水湖泊中的生源要素（如碳、氮、磷等）的生物地球化学循环过程进行系统的阐述和分析。
This article aims to explore in depth the biogeochemical cycles of biogenic elements in shallow lakes in the middle and lower reaches of the Yangtze River. As an important economic and cultural center of China, the shallow lake ecosystem in the middle and lower reaches of the Yangtze River has a crucial impact on the regional ecological environment and economic development. This article will systematically elaborate and analyze the biogeochemical cycling process of biogenic elements (such as carbon, nitrogen, phosphorus, etc.) inshallow lakes in this region.我们将概述长江中下游地区浅水湖泊的基本特征，包括湖泊的水文条件、生态环境和生源要素的分布状况。
在此基础上，我们将深入探讨这些湖泊中生源要素的生物地球化学循环过程，包括生源要素的输入、转化、输出和积累等关键环节。
液相色谱串联质谱临床检测方法的开发与验证
液相色谱串联质谱临床检测方法的开发与验证·189·检验医学2019年3月第34卷第3期Laboratory Medicine，March 2019，V ol. 34，No. 3液相色谱串联质谱临床检测方法的开发与验证中国医师协会检验医师分会临床质谱检验医学专业委员会摘要：液相色谱串联质谱（LC-MS/MS）是近年来发展极为迅速的新技术。
该技术结合了液相色谱的高分离性能和质谱的高敏感性、高特异性等优势，被广泛应用于化工、生物、医药、食品、临床医学、环境等领域。
在临床检验和诊断领域，LC-MS/MS作为传统诊断技术的补充，可提供更为准确、可靠的依据，使许多疾病得到准确、快速的诊断。
文章结合目前已公布的LC-MS/MS方法相关验证指南、文献及实际操作经验，系统介绍了LC-MS/MS方法开发的关键流程，并以25-羟基维生素D3 [25（OH）D3]为实例介绍方法验证的关键要素，为LC-MS/MS技术临床应用方法的建立、验证和实施提供参考。
关键词：液相色谱串联质谱；方法开发；方法验证Consensus of method development and validation of liquid chromatography-tandem mass spectrometry in clinical laboratories Clinical Mass Spectrometry Committee，Chinese Medical Doctor Association of Laboratory Medicine.Abstract：Liquid chromatography-tandem mass spectrometry （LC-MS/MS）is an emerging technology which has developed rapidly in recent years. It has combined the separation properties of liquid chromatography and the high sensitivity and specificity of mass spectrometry，which is widely applied in various areas，such as chemistry，biology，pharmaceutical science，food，clinic and environmental science. Especially in the field of clinical laboratory and diagnostics，LC-MS/MS used as a complement to traditional diagnostic techniques can often provide more accurate and reliable testingresults in accurate and rapid diagnosis of diseases. In this review，some internationally published LC-MS/MS method validation guidelines，related literature and practical experience were summarized，and some key processes of LC-MS/MS development were introduced. Using 25-hydroxyvitamin D3 [25（OH）D3] as an example，the key elements of method validation were reviewed，in order to provide a reference for the establishment，veri?cation and implementation of LC-MS/MS.Key words：Liquid chromatography-tandem mass spectrometry；Method development；Method validation 文章编号：1673-8640（2019）03-0189-08 中图分类号：R446.1 文献标志码： A DOI：10.3969/j.issn.1673-8640.2019.03.001近年来，各种检验新理论和新技术不断涌现，极大地推动了临床检验学科的发展。
生态鱼缸 观察日志
生态鱼缸观察日志英文回答：Ecological Fish Tank Observation Log.Day 1:Today, I set up my ecological fish tank. I carefully arranged the rocks and plants to create a natural habitat for the fish. I added water and turned on the filter and heater. The water temperature is set at 26 degrees Celsius, which is ideal for the fish I plan to keep. I also added some fish food to start the nitrogen cycle.中文回答：生态鱼缸观察日志。
第一天：今天，我设置了我的生态鱼缸。
我仔细地摆放了岩石和植物，以营造一个适合鱼类生活的自然栖息地。
我加入了水并打开了过滤器和加热器。
水温设置在摄氏26度，这对我计划饲养的鱼类来说是理想的。
我还加入了一些鱼食来启动氮循环。
Day 2:Today, I noticed that the water in the fish tank has become slightly cloudy. This is a normal occurrence during the initial stages of setting up a new tank. It is caused by the growth of beneficial bacteria that help break down the fish waste. I will continue to monitor the water parameters and make sure they are within the appropriate range.中文回答：第二天：今天，我注意到鱼缸中的水变得稍微浑浊了。
超分子溶剂萃取
第42 卷第 5 期2023 年5 月Vol.42 No.5559~567分析测试学报FENXI CESHI XUEBAO（Journal of Instrumental Analysis）超分子溶剂萃取/超高效液相色谱－串联质谱法测定血浆中他克莫司含量谢以清1，2，吕悦广2，孟宪双2，雷海民1*，马强2*（1．北京中医药大学中药学院，北京102488；2．中国检验检疫科学研究院，北京100176）摘要：该文建立了血浆中免疫抑制剂他克莫司（TAC）的超分子溶剂（SUPRAS）萃取/超高效液相色谱－串联质谱分析方法。
通过单因素实验结合响应面设计对超分子溶剂组成、用量及涡旋萃取时间等关键因素进行优化后，血浆样本以正戊醇、四氢呋喃和水形成的超分子溶剂进行高效萃取。
萃取液经Waters ACQUITY UPLC BEH C18（50 mm × 2.1 mm，1.7 μm）色谱柱分离后，在电喷雾质谱正离子模式下，以多反应监测（MRM）模式对他克莫司进行测定，内标法定量。
结果表明，他克莫司在0.5 ~ 30 ng/mL质量浓度范围内的线性关系良好，相关系数（r）为0.998 6；方法检出限和定量下限分别为0.1、0.5 ng/mL；在低、中、高3个加标水平下，平均回收率（n = 3）为91.9% ~ 99.9%，相对标准偏差（RSD）为1.7% ~ 5.7%。
所建立的方法快速、灵敏、稳定，适用于血浆中他克莫司的准确测定。
关键词：他克莫司；免疫抑制剂；超分子溶剂；血浆；超高效液相色谱－串联质谱中图分类号：O657.7；R917文献标识码：A 文章编号：1004-4957（2023）05-0559-09Determination of Tacrolimus in Plasma by Supramolecular Solvent Extraction/Ultra-high Performance Liquid Chromatography－Tandem Mass SpectrometryXIE Yi-qing1，2，LÜ Yue-guang2，MENG Xian-shuang2，LEI Hai-min1*，MA Qiang2*（1．School of Chinese Materia Medica，Beijing University of Chinese Medicine，Beijing 102488，China；2．Chinese Academy of Inspection and Quarantine，Beijing 100176，China）Abstract：An analytical method for the determination of tacrolimus（TAC） in blood plasma was estab⁃lished by supramolecular solvent（SUPRAS）extraction combined with ultra-high performance liquid chromatography－tandem mass spectrometry．After optimizing the key factors such as the composition and amount of SUPRAS，and vortex extraction time through single factor experiment and response sur⁃face design，blood plasma samples were extracted efficiently with SUPRAS formed by pentanol，tetra⁃hydrofuran and water．The extract was separated on a Waters ACQUITY UPLC BEH C18column （50 mm × 2.1 mm，1.7 μm），analyzed by electrospray ionization mass spectrometry in positive ion mode under multiple reaction monitoring（MRM） mode，and quantified by internal standard method．Experimental results demonstrated that there was a good linear relationship for TAC in the concentration range of 0.5－30 ng/mL，with a correlation coefficient（r） of 0.998 6．The limit of detection（LOD）and quantitation（LOQ） were 0.1 ng/mL and 0.5 ng/mL，respectively．The average recoveries（n = 3）at low，medium and high spiked concentration levels ranged from 91.9% to 99.9%，with relative stan⁃dard deviations（RSDs） of 1.7%－5.7%．The proposed method is rapid，sensitive and stable，and it was suitable for the accurate determination of TAC in blood plasma.Key words：tacrolimus；immunosuppresive agent；supramolecular solvent；plasma；ultra-high performance liquid chromatography－tandem mass spectrometry免疫抑制剂是用于抑制机体免疫力的药物，多用于抑制肝肾移植术后的免疫反应，以及治疗变态反应性和自身免疫性疾病，如类风湿关节炎、红斑狼疮等［1－3］。
快速消解分光光度法测定高氯废水中COD
快速消解分光光度法测定高氯废水中COD陈燕12毕军平12刘沛12秦迪岚12刘艳菊12龙雯琪12(1.湖南省生态环境监测中心，长沙410019#.国家环境保护重金属污染监测重点实验室"长沙410019)摘要：快速消解分光光度法利用COD快速测定仪，用较少取样量，缩短消解时间，操作步骤简单,20min可反馈结果，能大大提高工作效率&该方法检出限、精密度和准确度均能满足各种水质COD测定的要求&使用抗高氯试剂能准确测定含Cl浓度大于1000mg/L的高氯废水COD,表明快速法可替代重铬酸盐法和氯气校正法，大大提高高氯废水COD测定的工作效率，是一种简单、快速、准确、环保的检测方法，适合大力推广使用&关键词：快速消解分光光度法COD重铬酸盐法高氯废水DOI：10.3969/j.issn.1001—232x.2021.03.012Determination of COD in high chlorine wastewater by rapid digestion spectrophotometry.ChenYan1,2,Bi J unping1'2,Liu Pei1'2,Qin DHan1'2,Liu Yanju1'2,Long Wenqi1'2((1.Hu,nan Ecology and Environment Monitoring Center,Changsha410019,China;2.State Environmental Protection Key Laboratory of Monitoring for Heavy Metal Pollutants,Changsha410019,China)Abstract:Rapid digesting spectrophotometry uses COD rapid measuring instrument,which has the advantages of less sampling amount and simple operation procedures"and can submit results in20minutes,by which the working efficiency can be significantly improved.The detection limit,precision and accuracy of the rapid method can meet the requirements of COD determination in various water quality samples.By using anti-high chlorine reagent,the COD of high chlorine wastewater containing Cl-concen-tration more than1000mg/L can be accurately determined.It shows that the rapid method can replace the dichromate method and chlorine correction method,and remarkably improve the efficiency of COD determination of high chlorine wastewater.Key words:Rapid digestion spectrophotometry；COD；Dichromate method；High chlorine wastewater化学需氧量(Chemical Oxygen Demand,即COD)是指在强酸并加热条件下，用重铬酸钾作为氧化剂处理水样时消耗氧化剂的量&COD常作为衡量水中有机物质含量的指标，也是我国实施污染物排放总量控制的指标之一&氯离子能被重铬酸盐氧化，并能与反应催化剂作用生成沉淀，是影响.COD结果的主要因素&高氯废水是指氯离子浓度大于1000mg/L的废水&在对废水进行COD监测时常遇到水中氯离子含量过高的情况，如处理不当，则会使结果不真实甚至影响实验进展&在进行COD测定时，要避免氯离子含量过高带来的结果误差&《水质化学需氧量的测定重铬酸盐法》(HJ828—2017)(以下简称重铬酸盐法)和《水质高氯废水化学需氧量的测定氯气校正法》(HJ/T70—2001)是环境监测机构常用的COD检测方法，这两种方法虽然准确度高，稳定性好，但操作繁琐，耗时较长，至少4〜5h才能出结果，甚至更长，给工作带来很多不便+旧。
溶解氧对硝化反硝化的影响
溶解氧对硝化反硝化的影响英文回答：Dissolved oxygen (DO) plays a crucial role in the nitrification-denitrification processes. Nitrification, the oxidation of ammonia to nitrite and nitrate, is an aerobic process that requires the presence of DO. In contrast, denitrification, the reduction of nitrate to nitrogen gas, is an anaerobic process that occurs in the absence of DO.The interplay between DO and nitrification-denitrification has significant implications for wastewater treatment and environmental management. In wastewater treatment plants, maintaining optimal DO levels isessential for efficient removal of nitrogen. High DO concentrations promote nitrification, while low DO concentrations favor denitrification. By controlling DO levels, it is possible to optimize nitrogen removal and minimize the release of harmful nitrogen compounds into the environment.In natural ecosystems, DO fluctuations can influence the rates and pathways of nitrification-denitrification. In aquatic environments, DO levels can vary seasonally or diurnally, affecting the microbial communities responsible for these processes. In soils, DO concentrations can be influenced by factors such as soil moisture content and aeration, which in turn can impact the balance between nitrification and denitrification.DO also affects the production of nitrous oxide (N2O), a potent greenhouse gas. Nitrous oxide can be produced as an intermediate during both nitrification and denitrification. Under high DO conditions, nitrification dominates, resulting in reduced N2O production. Conversely, under low DO conditions, denitrification becomes more dominant, leading to increased N2O production.中文回答：溶解氧 (DO) 对硝化反硝化过程有着至关重要的影响。
地表水氨氮含量测定过程中的注意事项
5 000 mL 。
实验室根据采集水样的多少自行选择规格。
采集少量的水样通常选用2 500 mL 的规格。
下面就在湖泊某一指定深度采集三个平行水样为例来阐述有机玻璃采水器的使用注意事项。
采集水样根据要求是不能取湖面上方浮层，也不能将湖底的泥沙采集，所以一般是在湖深的1/2处进行取样。
当然取样前要用湖水将采水器和盛水器进行三次润洗，然后依次采集三个平行样。
有个问题很值得讨论：采水深度的确定。
根据有机玻璃采水器的工作原理即水是从采水器的下端进入的，所以采水深度确定时，要从采水器的底部算起。
在今年的工业分析与检验国赛试点赛上，多数参赛队对于采水深度的确定是错误的，他们没有搞清楚有机玻璃采水器的工作原理，直接从采水器上方开始算深度。
2 现场空白注意事项采集地表水检测氨氮含量时，通常空白是用无氨水来完成的。
要求把无氨水带到采集现场后，再进行空白取样，并且所加保护剂要和其他三个平行样所加的保护剂品种和量要尽可能一致。
采集空白样品要在现场完成，主要是为了使得空白和现场所处的温度，湿度完全一致，才能排除环境因素带来的误差。
3 保护剂的选择采集水样时，对于所加保护剂的要求是：经济并且对测定无干扰和无不良影响。
不同水样和不同的测定项目使用的保护剂要求是不一样的。
这里对于保护的使用级别是有严格要求的，为了避免系统误差，要求保护剂的纯度尽可能高，即保护剂0 引言地表水指的是陆地表面动态水和静态水的总称，主要包括液态水和固态水，主要有河流、湖泊、沼泽、冰川等[1]。
地表水是目前人类生活用水的主要来源之一，也是世界各国水资源的主要组成部分之一。
水溶液中的氨氮是游离的氮或离子氮，水中氨氮主要来源于天然水中的含氮物质的降解过程，还有目前另一个主要来源就是生活污水和工业废水。
氨氮在一定条件下可以转换成亚硝酸盐，生活中如果长期饮用含有氨氮的水，那么水中的亚硝酸盐会和人体内的蛋白质结合形成亚硝胺，是一种致癌物质，对人体的健康会造成很大的危害。
硝酸盐还原英语
硝酸盐还原英语Nitrate Reduction in EnglishNitrates are a class of chemical compounds that consist of a nitrogen atom bonded to three oxygen atoms. They are ubiquitous in the environment, playing a crucial role in various natural and anthropogenic processes. One of the most significant aspects of nitrates is their ability to undergo reduction, a process in which the nitrogen atom in the nitrate molecule is converted to a different form, often with important implications for environmental and industrial applications.The reduction of nitrates is a complex and multifaceted process that can occur through both biological and chemical pathways. In the natural environment, the reduction of nitrates is primarily driven by the activities of various microorganisms, such as bacteria and archaea, which utilize nitrates as an electron acceptor in their metabolic processes. This process, known as denitrification, is a crucial component of the global nitrogen cycle, as it helps to remove excess nitrates from aquatic and terrestrial ecosystems.The denitrification process involves a series of enzymatic reactions inwhich nitrates are sequentially reduced to nitrites, nitric oxide, nitrous oxide, and finally, molecular nitrogen. The enzymes responsible for these reactions are collectively known as nitrate reductases, and they are produced by a diverse array of microorganisms, including both heterotrophic and autotrophic species.The reduction of nitrates can also occur through chemical pathways, particularly in industrial and agricultural settings. In these contexts, the reduction of nitrates is often employed as a means of mitigating the environmental impact of nitrate-rich waste streams or as a method of producing valuable chemical products.One of the most prominent examples of the chemical reduction of nitrates is the production of nitric oxide (NO), a highly reactive gas that has a wide range of applications in both the industrial and medical fields. Nitric oxide is produced through the reduction of nitrates using various reducing agents, such as hydrogen gas or organic compounds. This process is particularly important in the production of fertilizers, as nitric oxide is a key precursor to the synthesis of ammonia, a critical component of many agricultural fertilizers.Another important application of nitrate reduction is the treatment of wastewater and the removal of excess nitrates from aquaticenvironments. In this context, the reduction of nitrates is often coupled with the use of biological denitrification processes, in which microorganisms are used to convert nitrates into harmless nitrogen gas. This approach is particularly valuable in addressing the problem of eutrophication, a phenomenon in which excessive nutrient inputs, including nitrates, can lead to the overgrowth of algae and the depletion of dissolved oxygen in aquatic ecosystems.The reduction of nitrates also plays a role in the production of certain pharmaceutical and industrial chemicals. For example, the reduction of nitrates can be used to synthesize various organic compounds, such as amines and nitriles, which are important building blocks for a wide range of chemical products.Despite the numerous benefits of nitrate reduction, there are also some potential drawbacks and challenges associated with this process. One of the most significant concerns is the potential for the formation of nitrite, a compound that can be toxic to both humans and the environment. Additionally, the reduction of nitrates can also lead to the production of other potentially harmful compounds, such as nitric oxide and nitrous oxide, which can contribute to air pollution and climate change.To address these challenges, researchers and industry professionals are continually working to develop more efficient andenvironmentally-friendly methods of nitrate reduction. This includes the development of new catalysts and enzymatic systems, as well as the optimization of existing processes to minimize the formation of unwanted byproducts.In conclusion, the reduction of nitrates is a complex and multifaceted process with a wide range of applications in both the natural and industrial realms. From the removal of excess nitrates in aquatic environments to the production of valuable chemical products, the reduction of nitrates plays a crucial role in shaping the world around us. As our understanding of this process continues to evolve, it is likely that we will see even more innovative and sustainable approaches to nitrate reduction in the years to come.。