过硫酸铵消化-硫酸铈催化分光光度法测定低浓度水碘

目的 探讨过硫酸铵消化-硫酸铈催化分光光度法测定低浓度水碘的效果和意义.方法 采用过硫酸铵消化-硫酸铈催化分光光度法测定低浓度含碘水样具良好的精密度和准确度.结果 排除常见系统误差和随机误差因素,能取得满意的线性、精密度和准确度.结论 采用过硫酸铵消化-硫酸铈催化分光光度法测定低浓度水样,操作简便、重复性好、抗干扰强等优点,值得临床推广     

食品中蛋白质的纳氏试剂分光光度测定方法

目的探讨纳氏试剂分光光度法测定食品中蛋白质的可行性。方法绘制纳氏试剂分光光度法标准曲线,测定该方法的检出限、灵敏度、精密度及准确度。结果该曲线相关系数为0.9992~0.9998,方法检出限为1.6μg,精密度为2.1%,灵敏度比国标第二法提高近4倍。在准确度方面,用该方法测定标准样品,结果与标准值的相对偏差(RD)为0.5%;样品加标回收率为96.1%~104.2%。结论测定食品中的蛋白质,与国标第二法比较,纳氏试剂分光光度法具有操作更简便、反应系统更稳定、线性更好、检出限更低、灵敏度、精密度及准确度更高的特点。     

生活饮用水中硝酸盐氮的3种测定方法的比较

目的比较3种不同方法(麝香草酚分光光度法、紫外分光光度法和离子色谱法)测定生活饮用水中的硝酸盐氮。方法通过3种不同方法的测试,分别从检出限、准确度、精密度和加标回收率进行分析和比较。结果2种化学方法测量范围较宽,能正确反映被测样本中硝酸盐的真实含量,但操作复杂、费时、费力而且实验废液对环境有一定的影响;离子色谱法无论从检出限、准确度还是精密度、加标回收率等方面均优于两种化学法。结论离子色谱法比另两种化学方法操作更简便快捷,准确、灵敏。     

分光光度法与离子色谱法测定饮用水中氰化物的比较

目的 采用异烟酸-吡唑酮分光光度法和离子色谱法分别测定饮用水中氰化物含量来对比分析2种方法的差异性。方法 使用紫外可见分光光度计和离子色谱仪分别对氰化物质控样和试剂样品进行对此测定,分析2种方法的精密度和准确度。结果 通过分析测定,离子色谱法测定饮用水中氰化物含量的精密度和准确度较分光光度法有所提高,其差异无统计学意义。结论 异烟酸-吡唑酮分光光度法的测试过程操作繁琐,稳定性较差,样品需要蒸馏预处理,试验耗时较长。离子色谱法分析操作简单,能够有效降低样品受污染的可能性并保证分析质量。     

浅谈PE900Z原子吸收分光光度计测定生活饮用水中钡参数选择

目的建立PE900Z原子吸收分光光度计测定饮用水中钡的正确参数。方法通过实验验证确定PE900Z原子吸收分光光度计测定生活饮用水中钡的最佳参数。结果以氯化钙做基体改进剂,硝酸为介质,采用镧涂层石墨管,优化石墨炉程序参数,检测结果精密度、准确度均有不同程度的提高。结论选择正确参数对PE900Z原子吸收分光光度计测定生活饮用水中钡结果至关重要。     

石墨炉原子吸收分光光度法测定食品中铅的研究

食品中铅的测定我国常用双硫腙比色法和原子吸收分光光度法,双硫腙比色法操作繁琐,随着监测手段的更新,原子吸收分光光度法迅速取代了化学法。由于本法干扰少、准确、操作简便、灵敏度高,已广为普及应用。我们在准确度、精密度及灵敏度方面对国家的标准方法进行了验证。同时采用过硫酸铵和二氯化钯作基体改进剂进行比较实验。实验证实用过硫酸铵作助灰化剂,对各类食品进行干法消化,均能获得满意的测定结果。     

两种仪器检测红细胞谷胱甘肽（GSH）的比较

目的提高红细胞谷胱甘肽测定的准确度和精密度。方法利用提供的方法采用两种仪器同时测定红细胞谷胱甘肽的含量。结果对73例健康体检人群的红细胞谷胱甘肽两种仪器的测定结果比较0．05无显著差异。结论日立牌7060全自动生化分析仪其结果的准确度和精密度均好于722型分光光度计，722型分光光度计测定较繁琐；而日立牌7060全自动生化分析仪操作程序化，省时、省力适合批量测定，值得推广。     

钼蓝分光光度法测定食品中复合磷酸盐的改进

目的对钼蓝分光光度法测定食品中复合磷酸盐进行改进。方法采用SnCl2作还原剂,与国标中钼蓝分光光度法测定食品中复合磷酸盐的方法进行对比。结果改进后,其标准系列线性良好,磷酸盐含量在0.08~100mg/L范围内符合比尔定律,相关系数r=0.9998,回归方程C=4.95A-0.022,最低检出浓度0.034mg/L。结论该法简化了操作过程,显色深,得到了较好的精密度和准确度。     

饮用水中高浓度挥发酚检测方法比较

目的 从检出限、准确度、精密度等方面比较分光光度法和流动注射法2种检测饮用水中高浓度挥发酚的方法,得到最佳检测方法。方法 4-氨基安替吡啉三氯甲烷萃取分光光度法和流动注射在线蒸馏法。结果 2种方法的方法学实验数据相差很小,都能准确可靠地检测低含量挥发酚。检测大批量含有高浓度挥发酚样品时,4-氨基安替吡啉分光法方法稳定,数据准确度高,精密度好,回收率稳定;流动注射在线蒸馏法极少情况下会出现个别样品重复性有差别状况。结论 4-氨基安替吡啉分光法方法非常稳定,准确度高,但实验过程繁琐,特别是在萃取的过程中易产生误差,影响准确度和精密度,同时有机试剂易对实验人员产生身体危害。流动注射在线蒸馏法检出限低、环境污染少,实验数据准确性高、精密度好。     

腌渍咸菜中硝酸盐含量测定方法的探讨

目的探讨紫外分光光度法测定成菜中硝酸盐含量.方法按样品处理程序处理好样品后,用紫外分光光度法和镉柱还原法,同时测定样品中的硝酸盐,对方法加以验证,并做方法的准确度和精密度试验.结果方法的平均回收率为96.3%,高低浓度的变异系数为1.1%和3.3%;两种方法无显著差异.结论紫外分光光度法测咸菜中硝酸盐简便、快速、减少污染.     

Chemical protective clothing standard test method development: Part II. Degradation test method

A "round-robin" interlaboratory evaluation of a proposed American Society for Testing and Materials (ASTM) standard test method was conducted for measuring the resistance of chemical protective clothing materials to degradation by liquid chemicals. The objective of this project was to determine the relative precision of the method and, where appropriate, recommend modifications that would improve reliability. In the round-robin format, eight laboratories used the proposed method to test each of five protective clothing materials against five liquid chemicals that are widely used commercially. The resulting data revealed that the proposed test method was not stringent enough to generate acceptable levels of accuracy and precision. Both intra- and interlaboratory standard deviations showed a high degree of variability in changes for the three physical properties evaluated. Changes in the method were identified which, if implemented, should improve accuracy and precision considerably.     

紫外分光光度法检测肝灵饮品中五味子醇甲的方法学研究

目的采用紫外分光光度法测定肝灵饮品中五味子醇甲进行定量检测，并对紫外分光光度法进行方法学研究。方法将肝灵饮品通过浓缩，定容，超声，稀释等步骤处理，用紫外分光光度计在254nm波长下检测五味子醇甲的含量。结果本方法在0．006～0．078mg／ml范围内线性关系良好，R^2=0．9995，回收率为98．33％-98．79％，相对标准偏差为0．34％～0．85％。结论该方法具有准确度高，精密度好，能够满足测定肝灵饮品中五味子醇甲含量的要求。     

ACL TOP全自动血凝分析仪的性能评估

目的：全面评估美国BECKMAN COULTER公司生产的ACLTOP全自动血凝分析仪。方法：从精密度、准确度、线性度、回收试验、抗干扰性及交叉污染率等方面对ACLTOP全自动血凝仪进行评估,并与ACL-Advance全自动血凝分析仪进行常规凝血指标比对。结果：ACLTOP全自动血凝分析仪的精密度、准确度、线性度、回收试验、抗干扰性及交叉污染率均较理想,与ACL-Advance的比对结果也较理想。结论：ACLTOP全自动血凝分析仪性能良好,所检测项目的结果可靠,完全能满足临床实验室的要求。     

工作场所空气中锡及其无机化合物样品预处理方法的改进

目的对工作场所空气中锡及其无机化合物样品的预处理方法进行改进。方法样品置于10mL比色管中,加入1mL浓盐酸置于90℃管式电热消解仪加热10—15min,取下放冷用去离子水定容至10mL经浓盐酸消化后,采用原子吸收分光光度计或原子荧光分光光度计进行测定。结果原子荧光分光光度计法在0．1～300μg／L浓度范围内线性关系良好,相关系数r=0．9996;检出限和定量下限分别为0．46μg／L和0．78μg／L,加标平均回收率为99％-102％;批内精密度为1．6％～2．98％;批间精密度为3．3％～5．5％。原子吸收分光光度计法在5～200μg／mL浓度范围内线性关系良好,相关系数r=0．9998;加标平均回收率为97％～101％;批内精密度为1．0％～1．5％;批间精密度为3．1％～5．5％。两方法对样品检测结果无显著性差异。结论两种方法均适用于工作场所空气中锡及其无机化合物的测定。     

An interlaboratory study of perfluorinated alkyl compound levels in human plasma

We conducted an interlaboratory study which differed from the typical study of this type because of its emphasis on comparing intralaboratory variability in results. We sent specimens to six laboratories experienced in the analysis of perfluorinated alkyl compounds in blood matrices and that use stringent procedures to control and assure accuracy and precision. Each received an identical set of 60 plasma specimens that were analyzed in six completely independent batches. Split specimens were included so that within- and between-batch coefficients of variation could be calculated. All laboratories used liquid chromatography-tandem mass spectrometry (LC-MS/MS). The concentrations of perfluorooctanesulfonate (PFOS), perfluorooctanoate (PFOA), and perfluorohexanesulfonate (PFHxS) measured in the specimens in general showed a high level of agreement, although in some cases the agreement was only moderate. The average within- and between-batch coefficient of variation for PFOS was 9.1% and 9.3%; for PFOA was 14.5% and 14.5%; and for PFHxS was 14.5% and 17.0%. The recent availability of labeled internal standards, among other advances, has facilitated improvement in the accuracy and precision of the assays. Considering the degree of between-subject variation in levels among people in background-exposed populations, the results indicate that biomarker-based epidemiologic studies of associations with health could have reasonable precision.     

Estimation of cercarial antigen efficiency by enzyme-linked immunosorbent assay (ELISA)

Cercariae were collected, hemogenized and the amount of protein was measured. ELISA was preformed by using 3 concentrations of cercarial Ag(2.5 ug/ml; 5 ug/ml and 10 ug/ml) also two types of sera were used; immune and non immune. Two dilutions (1:500 and 1:2000) of the conjugate were used in this test. The degree of absorbance was measured after 24 H by spectrophotometer, where the results showed that, the degree of absorbance was increased in the presence of immune sera and also in the presence of 1:500 conjugate concentration, but there was no difference in the degree of absorbance with the use of different Ag concentrations. It is obvious that 2.5 ug/ml of Ag could give very high ELISA readings with infected mice sera.     

Bayesian projections: what are the effects of excluding data from younger age groups?

Bayesian age-period-cohort models are used increasingly to project cancer incidence and mortality rates. Data for younger age groups for which rates are low are often discarded from the analysis. The authors explored the effect of excluding these data, in terms of the precision and accuracy of projections, for selected cancer mortality data sets. Projections were made by using a generalized Bayesian age-period-cohort model. Smoothing was applied to each time scale to reduce random variation between adjacent parameter estimates. The sum of squared standardized residuals was used to assess the accuracy of projections, and 90% credible intervals were calculated to assess precision. For the data sets considered, inclusion of all age groups in the analysis provided more precise age-standardized and age-specific projections as well as more accurate age-specific projections for younger age groups. An overall improvement in the accuracy of age-standardized rates was demonstrated for males but not females, which may suggest that analysis of the full data set is beneficial when projecting cancer rates with strong cohort effects.     

全自动石墨炉原子吸收法测定化妆品中镉

目的：研究化妆品中镉的测定方法。方法：取一定试样用浓硝酸水浴消化后，应用石墨炉原子吸收测定其镉的含量。结果：本方法测定化妆品中镉最低测定浓度为0．001mg／kg，回收率为95．5％～100．0％。结论：石墨炉原子吸收测定化妆品中的镉具有快速、准确、灵敏度高等优点，适于广泛使用和推广。     

Lab色度系统与人眼视觉感受在黑白度评价中的异同

[目的]探讨Lab色度系统与人眼视觉感受在评价黑白差异中的异同。[方法]采用Lab色度系统光谱光度计测量成对纸片黑白度差异(以L值差值表示),通过正常人群对每对纸片颜色深浅判别的正确率,分析Lab色度系统与人眼视觉感受的关系。[结果]L值差值在0~7时,人眼分辨正确率为20.00%~98.57%,男性较女性高,<40岁人群较>40岁人群高;当L值差值≥1时,67.14%的人视觉感受与Lab色度系统结果一致。[结论]Lab色度系统评价黑白差异时只有其差值≥1时,才能应用于美白化妆品的评价。