The Determination of Water in Freeze Dried Pharmaceutical Products by Performing the Karl Fischer Titration in the Glass Container Itself

A micro device is described by which it is possible to perform the Karl Fischer titration in the ampoule or vial containing a freeze dried pharmaceutical product. Using this device, it is not necessary to transfer the product from the original container into another vessel which means less manipulations to be performed and a lower risk to changes in moisture content during the analytical procedure.     

卡尔·费休法测定乳化炸药含水量

文章对乳化炸药中水分的存在形式进行了分析,并提出了一种适用于乳化炸药含水量的测定方法——卡尔·费休水分测定法。经过测定不同生产工艺、不同乳化剂的乳化炸药样品的含水量,并作重现性试验和回收试验,表明该方法在测量乳化炸药含水量时,具有测量时间短、精度高、测量结果重现性好等特点,适合在生产线或实验室进行推广应用。     

应用卡尔费休法测定膨化硝酸铵炸药的含水量

文章应用卡尔费休法测定膨化硝酸铵炸药的含水量,有效解决了WJ9026中蒸馏法在生产过程中应用时测试周期较长的问题,实现了膨化硝酸铵炸药在线水分的快速测定。通过与现行的几种工业炸药水分测定方法进行对比和验证试验后证实,卡尔费休法具有分析时间短、可进行连续反复测定、操作简便、测量精确度高、数据稳定、可靠等特点,是膨化硝酸铵炸药生产过程中一种重要的水分测定方法。     

卡尔•费休库仑法测量气体水分的研究

卡尔·费休库仑法是一种测定水分含量的经典方法,具有较高灵敏度和准确度,在气体水分含量测定领域具有一定的应用潜力。本文采用比较法研究卡尔·费休库仑法测量气体水分的准确度,即将湿度发生器产生的稳定湿气分别提供给经校准过的精密露点仪和卡尔·费休库仑法水分仪进行测定。研究起始漂移值和进样量等因素对测量结果重复性的影响,结果表明降低起始漂移值和增大进样量能提高测量结果的重复性;研究卡尔·费休试剂中甲醇含量对反应的影响,结果表明甲醇含量越低,示值误差越大;研究露点在-60~-16℃范围内卡尔·费休法的准确度,结果表明,在水分含量较高的范围(露点:-50.5~-19.9℃)内,卡尔·费休法露点示值误差较小0.4~2.6℃;在水分含量较低(露点:-58.1℃)时,卡尔·费休法露点示值误差为-5.9℃。上述研究结果对卡尔·费休库仑法用于气体水分含量的测定具有一定参考意义。     

Progress in Karl Fischer coulometry using diaphragm-free cells

Different designs of a semiopen, drainable cathode compartment of a medium-sized coulometric Karl Fischer (KF) cell for the determination of water in the range 0.1-500 microg were evaluated. The main criterion for the design was to keep the resistance between the anolyte and catholyte low enough to permit the generation of currents larger than 20 mA (for an output voltage of 28 V). It was found that a good compromise between the size of this current and a minimal influence from diffusing/migrating oxidizable reduction products from the catholyte was achieved by means of an interface having a channel length and diameter of 8 and 2.1 mm, respectively (catholyte volume, approximately 1 mL). To show the general applicability of the concept, the following different types of coulometric reagents suitable for nonpolar and polar samples, as well as for samples containing active carbonyl compounds, were investigated: Hydranal Coulomat A, AD, AK, AG-H (modified with chloroform, Merck), and two homemade methanolic reagents modified with 40% (v/v) chloroform and 50% (v/v) formamide, respectively. Except for Hydranal Coulomat A, the mean value of five consecutive titrations of 50 microg water did not deviate by more than 0.2% from the expected value for all reagents. Draining after every titration was sufficient to obtain accurate results, even for Coulomat A which, when used in the commercial diaphragm-free system of Metrohm, gave values which were about 10% too high. As compared to earlier reported results for diaphragm-free coulometry, the descibed modified cell represents a significant improvement, mainly because of the high accuracy achieved for all types of reagents.     

卡氏水分测定仪在甲醇检测中的应用

简要介绍了V20型卡尔费休自动微量水分测定仪在测定甲醇产品中微量水分方面的应用情况及与手动测定仪相比具有的优势。     

Conditions for accurate Karl Fischer coulometry using diaphragm-free cells

Factors influencing the extent of formation of oxidizable reduction products in coulometric cells used for Karl Fischer (KF) determination of water were investigated. For methanolic KF reagents buffered with imidazole (Im) or diethanolamine (DEA) (separately or in combination), three parameters were found to be of outmost importance: the cathodic current density, the pH, and the concentration of protonated base (ImH+ or DEAH+). For reagents buffered with only Im, the relative formation of oxidizable reduction products varied in the range 2-40%; i.e., 51-70 micrograms of water was found for a 50 micrograms water sample, depending on the above-mentioned parameters. The lowest values were observed for reagents having a pH around 10 in combination with cathodic current densities in the range 2000-5000 mA cm-2. For all the Imbuffered reagents investigated, the addition of modifiers such as chloroform, hexanol, and carbon tetrachloride was found to decrease the formation of oxidizable reduction products significantly. For example, a reagent buffered at pH 10 containing 1 M hexanol gave less than 0.3% formation in the current density interval from 200 to 4000 mA cm-2. The best reagents based on the above-mentioned modifiers were tested in the continuous coulometric mode with errors typically in the interval 0-0.5% using optimum conditions. One prerequisite for obtaining such small errors with diaphragm-free continuous coulometry is to use a cathode area no larger than 0.002 cm2. For some of the reagents based on both Im and DEA, the formation of oxidizable reduction products was close to zero at certain current densities, although the analytical performance was not as good as for the reagents buffered solely by Im due to longer conditioning and titration times.     

卡尔费休容量滴定法测定饲料中水分含量

建立卡尔费休容量滴定法测定饲料中水分含量方法,该法具有较高精密度和准确度,且操作简单、检测时间短,与国标法(GB6435-1986)相比,无显著性差异,可广泛应用于饲料中水分含量的测定。     

Source of the Difference between the Measurement of Water in Hydrocarbons As Determined by the Volumetric and Coulometric Karl Fischer Methods

The disparity between the volumetric and coulometric Karl Fischer methods for the measurement of water in hydrocarbons and hydrocarbon mixtures (oils) has been resolved. The amount of water detected by the volumetric method when the titration vessel solution is homogeneous is higher than that measured coulometrically or volumetrically when the titration vessel solution is heterogeneous. Water in oil that is not measured by the coulometric method when the oil is incompletely dissolved has been shown to reside in the oil phase of the heterogeneous (multiphasic) coulometric vessel suspension. Water that is not measured volumetrically under relatively low chloroform concentrations after the point of transition to a heterogeneous titration vessel solution is reached also appears to reside in the nonaqueous phase of the titration vessel solution. It appears that this water is retained in the hydrocarbon phase in a manner such that it is completely inaccessible to the volumetric or coulometric Karl Fischer reagents.     

卡尔·费休库仑法水分测量技术及其应用研究

运用卡尔·费休库仑法,对日本三菱公司的CA-06水分测定仪不能直接检测的固体、油品和气体中水分含量进行检测技术研究.组建了固体、油品及气体水分检测系统,试验验证检测结果准确、可信,使CA-06水分测定仪应用范围得以拓宽.将建立的检测技术应用到泡沫材料、气相白碳黑、桂树脂及高纯氢气中的水分含量检测,均获得了较好的检测结果.     

Efficiency of methods for Karl Fischer determination of water in oils based on oven evaporation and azeotropic distillation

The efficiency of azeotropic distillation and oven evaporation techniques for trace determination of water in oils has recently been questioned by the National Institute of Standards and Technology (NIST), on the basis of measurements of the residual water found after the extraction step. The results were obtained by volumetric Karl Fischer (KF) titration in a medium containing a large excess of chloroform (> or = 65%), a proposed prerequisite to ensure complete release of water from the oil matrix. In this work, the extent of this residual water was studied by means of a direct zero-current potentiometric technique using a KF medium containing more than 80% chloroform, which is well above the concentration recommended by NIST. A procedure is described that makes it possible to correct the results for dilution errors as well as for chemical interference effects caused by the oil matrix. The corrected values were found to be in the range of 0.6-1.5 ppm, which should be compared with the 12-34 ppm (uncorrected values) reported by NIST for the same oils. From this, it is concluded that the volumetric KF method used by NIST gives results that are much too high.     

Na_2EDTA滴定法测量水质总硬度的不确定度评定

以实验室水质总硬度样2017HB800001为例,对Na2EDTA滴定法测定水质总硬度的不确定度的来源进行评定,通过分析氧化锌标准溶液的配制,Na2EDTA标准溶液的标定,水样实际消耗Na_2EDTA标准溶液的滴定体积,水样吸取的体积及重复性的测量等因素进行总硬度测量的不确定度的评定,取包含因子k=2,则扩展不确定度:U=1.50及测定结果为:C=(270.87±1.50)mg/L,由此分析得出此水样产生不确定度的主要来源是样品溶液的测定和Na2EDTA标准溶液的标定。     

Karl Struss

Abstract

As a leading cameraman in Hollywood for five decades, Karl Struss received the first Academy Award for cinematography in 1929 and was an active figure in West-Coast pictorial photography during the years following World War I. As a still photographer, however, his most significant work dates from the years between 1909 and 1915.¹     

卡式水份滴定仪溃液体积的校准

概述卡式水份滴定仪的一般常识,介绍卡式水份滴定仪溃液体积的校准方法并评定溃液体积测量的不确定度.     

Preparation of Honey Reference Material for Water Content by Karl Fisher and Refractometric Methods

Certified reference materials are essential tools for calibration of measuring instruments, validation of analytical methods and assuring quality of measurement results. However, in the case of water content in honey, which is used to determine the quality and the marketability of honey, there is a lack of matrix reference materials. Certified reference material for water content in honey has been developed by the National Institute of Standards, Egypt. This article describes production of the material from processing to value assignment. Characterization of the material was carried out by refractometric and Karl Fisher titration procedures, where homogeneity and stability studies were carried out by Karl Fisher titration method. The measurement results were statistically analysed and weighted mean was calculated as assigned value. The certified value and expanded uncertainty were found 16.24 ± 0.33 g/100 g, respectively.     

酸碱滴定法测定芳香族胺纯度及滴定突变影响因素探讨

芳香胺及其衍生物是环氧树脂十分重要的一类固化剂,纯度是其最主要的指标。本文对酸碱滴定法测试芳香族胺纯度的原理进行探讨,建立以E对V滴定曲线的一阶导数法求取终点测定芳香胺纯度的酸碱滴定方法,方便快捷,并对滴定突跃的若干影响因素进行分析讨论。     

高锰酸盐滴定法(COD)测定仪校准方法探讨

本文基于高锰酸盐滴定法(COD)测定仪的工作原理及计量特性,以电子天平和电子秒表作为主标准器,提出相应的校准方法,并应用该方法对某公司生产的高锰酸盐滴定法(COD)测定仪进行校准。分析结果表明,该校准方法科学合理,操作简便、适用性强,可供相关仪器使用者和计量工作者参考。     

智能光度滴定仪及其在酸碱滴定中的应用

由便携式光谱测定仪（POPS-15）和数字滴定管（DAB-1）组成的智能光度滴定仪实现了滴定过程的全谱适时监测,系统能根据三维滴定曲线自动判定滴定终点,自动给出测定结果。酸碱滴定的标准偏差为0．014mL。