光度法测定结晶紫含量

采用荧光光度法测定水产品中结晶紫残留量。样品在pH=5．00的H3PO4-NaOH缓冲液中,激发波长为530nm、吸收波长为600nm的条件下测定荧光值,在1．00×10^-6g／mL～1．00×10^-11g／mL范围内,有良好的线性,相关系数R=0．9996;检出限为1．58×10^-12g／mL;回收率在95．0％-98．0％之间。本法具有操作方便、检出限低、较高的重现性及准确性等特点,是一种良好的分析检测方法。     

酶催化荧光法测定盐酸肾上腺素

利用盐酸肾上腺素对血红蛋白模拟酶催化荧光体系的猝灭作用,建立了酶催化荧光法测定盐酸肾上腺素的新方法。研究了该猝灭体系的最佳实验条件及动力学行为,测定的线性范围为1．5×10^-7-2．2×10^-6,检出限为3．4×10^-8mol／L。对浓度为1．2×10^-6mol／L的盐酸异丙嗪进行11次平行测定,其相对标准偏差为2．7％。该法已成功的应用于药物制剂中盐酸异丙嗪含量的测定。     

流动注射化学发光法测定盐酸利多卡因

基于盐酸利多卡因对鲁米诺-过氧化氢化学发光反应的增敏作用,结合流动注射技术,建立了流动注射化学发光反应测定盐酸利多卡因的新方法。该方法的线性范围为8．0×10^-8～5．0×10^-6g／mL,检出限为1．2×10^-4g／mE。对5．0×10^-7g／mE的盐酸利多卡因进行11次平行测定,相对标准偏差2．5％,方法简单、快速、灵敏。该法已用于针剂中盐酸利多卡因含量的测定。     

新催化光度法测定铝土矿中锰含量

建立了新催化动力学光度法测定铝土矿中锰含量的方法。该方法的线性范围为0μg／L～3．2μg/L,检测限为3．5×10^-6g／L,相对标准偏差RSD=0．93％（n=11）,回收率98．00％-100．33％,测定结果与国家标准方法一致。用此法进行铝土矿中锰含量的测定,具有操作容易、结果准确、重现性好的特点。     

火焰原子吸收光谱法测定岩矿中金含量的测量不确定度评定

采用《测量不确定度评定与表示指南》,以火焰原子吸收光谱法测定岩石矿样中的金含量为例,对测量结果进行不确定度评定。分析了不确定度的重要来源,包括样品制备,标准工作溶液,工作曲线拟合,试液定容体积及测量重复性等引入的不确定度分量组成。当金平均含量为2．98×10^-6±0．36×10^-6（k=2）,评定其扩展不确定度为0．36×10^-6。     

乳癖消贴片中标示成分及残留溶剂的含量测定

建立了贴片中标示成分芍药苷含量的HPLC分析方法和贴片中各种残留溶剂含量的GC分析方法。样品经甲醇提取,离心分离后,以乙腈-水（体积比16：84,HAc0．4％）为流动相,选择ODS-2Hypersil C18（4．6mm×150mm,5μm）色谱柱,测定芍药苷含量。贴片基质经处理,以GC内标法测定残留溶剂含量。结果表明HPLC法的精密度、重现性和回收率良好;GC分析测得乙酸乙酯、异丙醇、乙醇三种残留溶剂,贴片中残留溶剂总量为2．1×10^-4。     

苯醚甲环唑残留量的气相色谱分析方法研究

建立了气相色谱法测定香蕉果肉、全果和土壤中苯醚甲环唑残留量的分析方法。实验结果表明：添加量为0．02～2．0mg／kg时．果肉、全果和土壤中的平均回收率分别为：86．88％-98．52％、83．80％-96．01％和94．00％～97．27％．相对标准偏差分别为2．77％～5．74％、3．98％-6．11％和2．76％-5．32％,方法的最小检出量为2．0×10^-12g．最低检出浓度为0．002mg／kg。方法快速、灵敏度高、重现性好,具有较好的准确度和精确度．可用于环境系统中的苯醚甲环唑的残留检测分析。     

电感耦合等离子体质谱法测定土壤中砷的含量

利用电感耦合等离子体质谱法（ICP—MS）测定土壤中砷的含量。样品经过微波消解,在线加入内标校正基体效应,通过修正方程校正质量数干扰。测定砷元素校正曲线的相关系数0．9999,检出限0．01mg／kg,样品分析结果的变异系数为1．6％～2．4％（n=6）,加标回收率在84．0％-96．8％。同时采用国家标准方法氢化物-原子荧光光度法验证了方法的准确度,两种方法结果无显著差异。实验结果表明,该方法具有简单、快速、检出限低等特点,可用于土壤中砷含量的测定和监控。     

纳米碳管和纳米二氧化硅修饰玻碳电极示差脉冲伏安法测微量铜

本文用纳米碳管和纳米二氧化硅修饰的玻碳电极以1mol/LH2SO4为底液测定Cu^2＋,方法是先在-0．5V进行预还原120s,然后用示差脉冲伏安法进行阳极扫描,发现在-0．04V（vs．SCE）处出现铜的氧化峰,且峰电流与Cu^2＋的浓度在5．0×10^-8～1．0×10^-2mol/L范围内呈良好的线性关系,该方法的检出下限为1．0×10^--8mol/L。用标准加入法测得回收率范围为92．3％～104．2％,相对标准偏差（RSD）为3．5％。将此电极用于实际样品的测定,取得较好的结果。     

填充柱气相色谱法测定有机溶剂中的水

气相色谱法测定有机溶剂中水的含量，采用自制填充柱及热导池检测器，通过对不同有机溶剂的测定，优化了测试方法和条件。乙醇溶剂中水含量在1．0～9．0×10^2g/L范围内呈线性关系，相关系数R=0．9955，最低检测限为1．0×10^-1g/L。方法简单、灵敏度高、重现性好。测定了油漆稀释剂、酒类等样品，得到满意测定结果。     

A new approach to characterize scratch and mar resistance of automotive coatings

Mar damage is a major customer concern of the automotive coatings industry. Our study of mar performance can be separated into two distinct areas, a detailed understanding of the damage formation mechanism, and an investigation of the relationship between the damage morphology and appearance. We have developed a nanoscratch technique that can measure important physical quantities, such as penetration depth, normal force and tangential force during the formation of the scratch. Mar resistance of three coatings was evaluated and compared based on the damage mechanisms: plastic flow and fracture. The different deformation mechanisms result in different damage morphologies and a corresponding change in visual impact of the scratch. Statistical surveys of appearance of well-defined scratches indicate that in very short observation times, scratches where fracture has occurred are much more visible than those made by plastic deformation alone. However, with sufficient time and strong illumination a significant percentage of observers could see plastic deformation as well.     

注射成型锁模力重复精度影晌因素的研究

讨论了传统锁模力重复精度测试方齿的特点，使用瑞士Baumer 锁模力感测仪研究了锁模力重复精度的影响因素。结果表明，开合模位置以及开合模速度的变化对锁模力重复精度的影响可以忽略不计；基于Baumer锁模力感测仪的锁模力重复精度测试方法相比于传统测试方法具有操作简单、搞笑精确的特点。     

微波化学反应器与实验结果的重复性

对基于家用微波炉改装的微波化学反应器建立模型，用有限元方法联合求解麦克斯韦方程和热传导方程并考虑了介电常数随温度和时间的变化，得到烧杯中溶液的温度分布。计算发现烧杯在反应器腔体中摆放的位置对加热效果有着显著影响。而化学反应是一个非平衡体系，这种位置差异带来的影响会更加明显。通过实验进一步验证了以上结论，并且发现：由于反应器磁控管的不稳定性，即使烧杯位于相同位置，多次实验的结果也不相同。因此，基于家用微波炉改装的微波化学反应器很难保证微波化学实验的重复性。     

七种亚硝化反硝化聚磷菌的生长特性研究

亚硝化反硝化聚磷菌(NDPAOs)以亚硝酸盐为电子受体,具有同时脱氮除磷的特点,能够最大程度地减少碳源和氧气需求,因此可以大大减少能耗,节约成本。试验研究了7种NDPAOs——肠杆菌属(Ent.)、葡萄球菌属(Sta.)、副球菌属(Par.)、泛菌属(Pan.)、克雷伯氏菌属(Kle.)、芽孢杆菌属(Bac.)和莫拉氏菌属(Mor.)的释磷特性,并以纯培养的方式研究了它们的生长特性。结果表明,缺氧反应20 h后,Sta.、Bac.、Par.、Kle.、Pan.、Ent.和Mor.的单位细胞吸磷量分别为1.98×10-11、1.64×10-11、1.43×10-11、1.13×10-11、9.59×10-12、7.72×10-12和6.28×10-12mg/cfu。Ent.、Kle.、Bac.、Pan.、Par.、Sta.和Mor.的缓慢期几乎都处于0～6 h之间,对数期分别为6～144、6～72、6～96、6～52、6～31、6～96和6～72 h。Par.、Sta.、Pan.和Mor.的对数期的生长速率较Ent.、Bac.和Kle.的小。不同菌属的亚硝化反硝化聚磷菌的生长特性也不完全相同,特别是对数期的生长速率以及维持的时间相差较大。     

Repeatability and intermediate precision of a mass concentration calibration system

Many aerosol instruments require calibration to make accurate measurements. A centrifugal particle mass analyzer (CPMA) and aerosol electrometer can be used to calibrate aerosol instruments that measure mass concentration. To understand the sources of uncertainty in the calibration method, two CPMA-electrometer systems were tested to measure the repeatability and intermediate precision of the system, where the repeatability is the standard deviation of several measurements using the same system over a short period of time, and the intermediate precision is the standard deviation of several measurements using different instruments with different calibrations over a long period of time. It was found that the repeatability of the CPMA and the aerosol electrometer were both 0.8%, while the intermediate precision was 1.3% and 2.2%, respectively. The intermediate precision of the aerosol electrometers determined here compares well with a broader study by national metrology institutes which determined an intermediate precision of ～1.7%. By propagation of uncertainty, it is expected that a CPMA-electrometer system would have repeatability of 1.1% and an intermediate precision of ～2.1%. This compares favorably to thermal-optical analysis methods which aim to measure black carbon mass concentrations for instrument calibration, which have a repeatability in the range of 8.5–20% and reproducibility in the range of 20–26% for elemental carbon. Thus, the CPMA-electrometer method may be a good alternative to existing instrument calibration procedures.

Copyright © 2019 American Association for Aerosol Research     

Total Acid Number Determination of Biodiesel and Biodiesel Blends

The repeatability and accuracy of the total acid number (TAN) measurement for soy oil-based biodiesel–diesel blends using the ASTM D664 method was studied. ASTM D664 is the standard reference method for measuring the acid number of both biodiesel and petroleum-derived diesel, which specifies procedures for the determination of acidic components in biodiesel and diesel, and claims good repeatability and mediocre reproducibility during application, but cites no information on accuracy. However, the accuracy of this method is very important for setting the specifications for biodiesel blends, especially for B20 (a mixture composed of 20% biodiesel with 80% diesel) because of its wide commercial production. The accuracy of ASTM D664 was measured to be within 4.13% for B20 in the acid number range of 0.123–0.332 mg KOH/g. The maximum repeatability was approximately 5.21% at an acid number of 0.123 mg KOH/g. Within the ASTM D6751-07b specification for TAN (0.5 mg KOH/g), good accuracy and repeatability were also obtained. Accuracy specification and electrode operation suggestions for ASTM D664 are also given.     

碘量法测定黄花蒿中青蒿素含量

为了快速简便准确测定黄花蒿中青蒿素含量,利用碘量法建立一种青蒿素的测定方法。使用间接碘量法,以淀粉为指示剂,硫代硫酸钠为滴定剂,测定黄花蒿的石油醚提取液中青蒿素含量。通过稳定性、重现性、线性关系考察和加样回收率等指标考察方法的可行性。碘量法测定黄花蒿中青蒿素含量具有良好的线性关系,重现性、稳定性和加样回收率满足分析要求。     

用卡尔费休库仑法测定橡胶中的水分含量

采用卡尔费休库仑滴定法测定了橡胶中的水分含量,研究了环境水分、漂移值、加热温度、载气流量、试样量等因素对测定结果的影响,确定了方法的重复性和再现性。结果表明,选择干燥氮气作为载气、载气流量为50～70 mL/min、漂移值为20μg/min和试样量为0.5～1.0 g时,该测定方法的重复性较好。当水分质量分数小于0.5%时,实验室内的重复性小于0.019%,实验室间再现性小于0.053%。     

Stability of ceramic color reflectance standards

This article reviews the long-term repeatability of spectrophotometric color measurements of ceramic color standards calibrated by Hemmendinger Color Laboratory (HCL) since it was founded 25 years ago. A set of twelve BCRA tiles was measured at HCL in 1977, and a few months later at NBS. The CIELAB color-difference, averaged over the twelve tiles, between HCL and NBS was 0.25 units. Measured at HCL about every four months since that time, the repeatability of measurement, averaged over the twelve tiles, has been better than 0.15 CIELAB units. The difference from the NBS measurements has remained at about 0.25 units over two decades. From these data the conclusion can be drawn that the tiles have not changed color during this period of time by an amount exceeding the limits of instrumental repeatability, namely about 0.15 units. © 1998 John Wiley & Sons, Inc. Col Res Appl, 23: 408–415, 1998     

Repeatability assessment of large‐scale fire experiment involving water spray system in a forced ventilated compartment

Repeatability of large‐scale fire test remains a key issue for code validation process. Most of the large‐scale experimental studies are based on single experiment, and the influence of repeatability is barely considered in the test analysis process. Due to the substantial cost, reproducing several trials of a given large‐scale fire scenario is not often performed. In the framework of the OECD PRISME 2 project, this topic has been identified, and a specific large‐scale fire test has been reproduced twice in the final goal of assessing the level of repeatability. The scenario is an oil pool fire in an enclosure mechanically ventilated and during which a water spray system is activated. The analysis consists in identifying a set of variables on which metrics is applied in order to quantify the levels of discrepancy between the two tests. A set of 27 variables are selected such as they characterize the whole fire scenario (the fire source, the gas phase, walls, the ventilation network, and the water spray system). The analysis points out that the repeatability levels are different depending on the type of variable. The gas temperature or species concentrations are more repeatable than gas pressure or air flow rate. In addition, a new methodology is proposed in comparing, for each physical variable, the variations due to repeatability (ie, the precision) and the uncertainty. A new metric is proposed helping modelers in code validation process.