化学分析方法验证和确认的应用研究

分析方法的验证/确认是实验室引进新方法时必做的工作,也是实验室技术工作的重点和难点之一。对实验室采用分析方法的验证和确认工作进行归纳总结,详述了分析方法选择性、测量范围、线性范围、检出限和定量限、精密度、准确度的验证/确认方法及结果判定方式。适用于实验室引进的标准方法(包括标准变更)和非标准方法(实验室设计/制定的方法、超出预定范围使用的标准方法、扩充和修改过的标准方法)的验证和确认。     

检出限的涵义和计算方法

介绍仪器检出限、方法检出限及样品检出限的基本定义及涵义,以气相色谱法测定海水中的十氯酮为例,进行不同方法的检出限计算,讨论了不同方法计算检出限引起的差异及计算方法中所选取参数的合理性,对如何科学使用检出限进行实验室质量控制提出了建议.     

水中氟化物国际标准检验方法的验证及其比较

介绍水中氟化物国际标准检验方法的验证结果,其中包括了干扰实验、标准曲线、准确度、精密度、检出限等.并将本方法测定结果与国标同类方法进行了比较.结果表明,该方法抗干扰性好,测量精度高,其标准曲线范围宽,点数设计合理,优于国标中的同类方法.应加以采纳和推广.     

利用能力验证结果评价参加实验室的整体检测能力

能力验证是利用实验室间比对确定实验室检测能力的活动,其评价结果多用于评估单个实验室的检测能力。行业监管部门期望掌握实验室整体能力和检测方法的相关信息,为分析参加实验室的整体检测能力和不同测试方法的差异,分析了3年航空煤油检测能力验证结果,采用满意结果百分比、|Z|值平均值随参加能力验证次数的变动情况,证实了能力验证对整体检测能力的改进作用;利用异方差t检验,比较不同测试方法结果的一致性和精密度差异;通过比较能力验证评价标准差和检测标准的精密度要求,评价参加实验室整体检测能力是否符合检测标准要求。研究表明,能力验证数据能够用于定量分析参加实验室的整体检测能力,为行业实验室监管和检测方法间比对提供依据。     

利用改进的胶束电动毛细管色谱法和液相色谱法测定6类重点食品中的脱氢乙酸

改进了实验室建立的测定脱氢乙酸的胶束电动毛细管色谱(MEKC)和国标的液相色谱(LC)的分离及样品前处理方法.改进后的两种方法均能准确测定6类重点食品中的脱氢乙酸,为重新评估脱氢乙酸的风险、修订或制定其在不同食品中的限量标准提供依据.改进后的MEKC和LC方法的检出限及定量限分别为0.2、0.5 mg/L和0.05、0...     

色谱峰纯度的定性方法

较系统地介绍了近年来国内外文献中有关色谱峰纯度的定性方法──仪器方法和化学计量学方法。仪器方法重点介绍了归一化比较光谱、吸收比法、光谱抑制法及导数技术。化学计量方法介绍了主成分分析法和渐近因子分析法。通过对文献方法和应用的简单介绍,比较了各种方法的特点及优缺点,总结了规律。     

室内空气中甲醛的检测方法研究

甲醛在室内环境污染控制标准中限量最低,而规定的检测方法中只有酚试剂光度法的检出限低,能判别Ⅰ类工程的测量值是否超标。本文对国家标准中的乙酰丙酮光度法的测定条件,如显色温度、时间、比色皿长度等作了改进,使方法的检出限降至0.008 mg/m3。本法经6个有资质的实验室验证,结果准确、重现性好、分析成本低。     

用质控图法和稳健统计法评估固体样品汞含量热裂解-原子吸收法测量不确定度

基于实验室长期积累的质控数据评估测量不确定度的top-down方法具有广泛应用前景,质控图法和稳健统计法是其中常见方法。质控图法要求测量数据中不含离群值,对测量数据时间顺序有明确要求。稳健统计法是指不用识别、剔除离群值,直接应用全部测量数据,将离群值对统计分析结果影响降低到最小的统计分析方法。本文基于质控图法、稳健统计和实验室长期积累的质控数据对固体样品汞含量热裂解-原子吸收分析方法的测量不确定度进行了评估,对两种方法计算结果、实验室评估的测量不确定度和标准样品标称值的不确定度进行了比较。计算结果表明,两种方法结果基本吻合,基于实验室质控数据期间精密度评估的不确定度明显小于标准样品标称值,结果合理。     

用质控图法和稳健统计法评估热裂解-原子吸收光谱法测量固体样品汞含量的不确定度

基于实验室长期积累的质控数据评估测量不确定度的top-down方法具有广泛应用前景,质控图法和稳健统计法是其中常见方法。质控图法要求测量数据中不含离群值,对测量数据时间顺序有明确要求。稳健统计法是指不用识别、剔除离群值,直接应用全部测量数据,将离群值对统计分析结果影响降低到最小的统计分析方法。基于质控图法、稳健统计和实验室长期积累的质控数据对固体样品汞含量热裂解-原子吸收光谱分析方法的测量不确定度进行了评估,对两种方法计算结果、实验室评估的测量不确定度和标准样品标称值的不确定度进行了比较。计算结果表明,两种方法结果基本吻合,基于实验室质控数据期间精密度评估的不确定度明显小于标准样品标称值,结果合理。     

大气环境降水监测的质量控制方法

根据《环境监测质量管理规定》、《江苏省环境监测质量管理实施细则》及环境监测技术规范的要求,探讨了降水监测采样、样品保存技术、实验室分析的质量控制方法。采用不同采样方法、不同采样器同时采集15场降水,其降雨量、电导率、pH值的比对监测结果合格率均大于90%。经试验,降水各组分有效保存时间不同,其中NO_3~-,NH_4~+为3 d;F~-,Cl~-,SO_4~(2-)为14d;K~+,Na~+,Ca~(2+),Mg~(2+)为30 d。选择2家实验室对降水样品、空白样品、标准样品同时测试,结果显示,空白测定结果均低于方法检出限,标准曲线相关性系数r≥0.999 0,测定结果的相对标准偏差为1.4%~5.9%(n=6),加标回收率为89.8%~106%,标准样品的分析结果均合格。该方法能保证降水监测结果准确、可靠,满足HJ/T 165-2004《酸沉降监测技术规范》的要求。     

Dichroism of absorption and polarization of phosphorescence of molecules of the closed form of nitrobenzospirothiopyran

The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997.     

Synthesis of phenolic components of Grains of Paradise

Two vanilloids, (5E)-8-(4-hydroxy-3-methoxyphenyl)oct-5-en-4-one (1) and 4-[3-hydroxydecyl]-2-methoxyphenol (2), isolated from the dried seeds of Grains of Paradise (Aframomum melegueta), were synthesized; the latter compound was made as the S-enantiomer and the material derived from the seeds was found to be a 1:1.7 mixture of the R and S isomers. The synthetic route used should allow the preparation of analogs having extended alkyl chains and consequently different lipophilicity, and 3, a homolog of 2, was also prepared.     

非那雄胺合成工艺改进

非那雄胺能抑制5α-还原酶的活性,明显降低二氢睾酮水平,是一种治疗良性前列腺增生的有效药品。该合成工艺以甾烯酮酸为原料,将其与氯化亚砜反应,无须分离即与叔丁胺反应得17β-酰胺化合物,再氧化开环,环合,氢化,脱氢合成了非那雄胺。经元素分析、IR、1HNMR、13CNMR、MS分析表征了其结构。该法无须使用昂贵的2,2-二吡啶二硫化物和剧毒药品苯亚硒酸酐,且以乙酸铵代替氨气,降低了对设备的要求和腐蚀,更适用于工业生产。     

Study of hydration of two cements of different strengths

Main hydration products of two cement pastes, i.e. CSH-gel, portlandite (P) (and specific surface S) were studied by static heating, and by SEM, TEM and XRD, as a function of cement strength (C-33 and C-43) hydration time (th) and subsequent hydration in water vapour.Total change in mass on hydration and air drying, M_o, increased with strength of cement paste and with hydration time. Content of water escaping at 110 to 220°C, defined as water bound with low energy, mainly interlayer and hydrate water, was independent on cement strength but its content increased with (th). Content of chemically bound (zeolitic) water in CSH-gel, escaping at 220-400°C, was slightly dependent on strength and increased with (th). It was possibly derived from the dehydroxylation of CSH-gel and AFm phase. Portlandite water, escaping at 400-500°C, was independent on cement strength and was higher on longer hydration. Large P crystals were formed in the weaker cement paste C-33. Smaller crystals were formed in C-43 but they increased with (th). Carbonate formated on contact with air (calcite, vaterite and aragonite), decomposed in cement at 600-700^oC. It was high in pastes C-33(1 month) and C-43(1 month), i.e. 5.7 and 3.3%, respectively; it was less than 1% after 6 hydration months (low sensitivity to carbonation) in agreement with the XRD study showing carbonates in the air dry paste (1month), and its absence on prolonged hydration (6 months) and on acetone treatment. Water vapour treatment of (6 months) pastes or wetting-drying increased this sensitivity.Nanosized P-crystals, detected by TEM, could contribute to the cement strength; carbonate was observed on the rims of gel clusters.This revised version was published online in November 2005 with corrections to the Cover Date.     

Determination of heats of detonation and influence of components of composite explosives on heats of detonation of high explosives

The heats of detonation of 20 simple high explosives and explosive mixtures were determined by means of an adiabatic detonation calorimeter designed by the authors. The results indicated that the performance of the instrument was reliable and the experimental data were very accurate. For explosive mixtures, there was a linear accumulative relationship between the heats of detonation of the explosive mixture and its components. Accordingly, the heats of detonation of explosive mixtures could be calculated directly from the heats of detonation of simple explosives and the characteristic heats of other components. The experiments showed that the gold or brass shell of the cylindrical charge could be substituted by a thick-walled porcelain shell, which had the advantage of cheapness.

     

恶臭嗅辨实验室建设探讨

针对恶臭测试的环境影响问题,提出了解决的实例方案,并对方案的要点及优缺点进行讨论,此方案在实际操作中具有较好的效果。     

Investigation of Kinetics of Solid-Phase Synthesis of Lithium Orthosilicate

The kinetics of the interaction between lithium carbonate and silica with various degrees of dispersion was investigated by TG and DTA methods. It was found that the utilization of pyrogenic silica with a specific surface area of about 300 m²g^-1 instead of aerosil with one of 175 m²g^-1 leads to an increase of the reaction rate between lithium carbonate and silica, which depends on the formation and growth of lithium orthosilicate crystals in the first stage, and is conditioned by the diffusion of lithium and oxygen ions through the lithium orthosilicate layer formed at temperatures above 800 K. This supposition is supported by the kinetic analysis results obtained with the use of the different models. The optimal regime of heating is recommended. This revised version was published online in July 2006 with corrections to the Cover Date.     

小环化合物中饱和碳质子化学位移的计算

小环化合物由于其张力、构型、构象和各向异性效应等原因,环碳上质子化学位移缺乏规律性,难以预测,对此作者曾提出一种近似算法。本文根据303种小环化合物中饱和碳质子的化学位移实验数据,将适于计算这类质子化学位移的公式表述为:     

解决能源问题的新途径--光解水制氢的研究

面对日益枯竭的能源危机,氢能是一种洁净、最有前景的替代能源。目前在各种制氢的方法中光催化分解水制氢的研究最多,光解水过程中催化剂最关键,本文对利用太阳能光解水的途径、提高光催化反应效率以及光催化剂的开发研究进行了综述。