AMicro-sized headspace GC technique for determination of organic volatile impurities in water-insoluble pharmaceuticals

Summary A micro-sized headspace technique is presented for determination of organic volatile impurities (OVIs) in water-insoluble pharmaceuticals. Its main features include reduction of the amounts of sample of drug and sample dissolution medium, from 100–200 mg and 1–5 mL, respectively, in the traditional headspace method to 5–30 mg and 100 μL in the micro-sized headspace method, and shortening the headspace equilibration time from 45–60 min to 5–10 min. The validity of method has been examined both experimentally and theoretically. The relative standard deviation of the analysis and the linearity of method satisfied the requirements of the United States Pharmacopoeia. It was found that headspace equilibrium conditions have little influence on the sensitivity of the method, and that the presence of different amounts of drug substance in the sampling solution has little effect on the analytical results, in contrast with the traditional headspace GC method.     

顶空-气相色谱法进展

回顾了顶空采样气相色谱分析法在复杂基质中挥发性成分中的应用．总结并详述了顶空分析的三种重要模式-介绍了顶空分析的相关原理和整个顶空分析系统的参数优化过程．综述了顶空．气相色谱分析在生物样本中挥发性有机物的测定、药品中有机残留溶剂的检测、聚合材料中挥发性有机物的分析、环境中有害的有机挥发性物质分析、挥发油分析和烟草分析等方面的进展．     

化妆品中挥发性有机溶剂的通用检测方法

以化妆品配方中常见及禁用的36种有机溶剂为研究模板,建立了化妆品中挥发性有机溶剂残留评价初筛知识库、确证知识库和定量方法。初筛知识库包括双柱保留指数知识库和NIST质谱库。双柱保留指数知识库以保留指数为定性指标,选择极性的VF-1301ms和非极性的DB-5ms两根色谱柱,用顶空气相色谱-质谱法考察了36种有机溶剂在两种色谱分离系统中的保留特性。利用NIST MS search 2.0作为检索工具,同时建立了36种挥发性有机溶剂的顶空气相色谱-质谱定量方法。样品经60 ℃、30 min静态顶空后以连接了VF-1301ms石英毛细管色谱柱的气相色谱-质谱仪检测,外标法定量。方法检出限为0.01~3.3 μg/g,加标回收率为60.77%~126.60%。该方法从通用性的角度,为化妆品中挥发性有机溶剂残留的筛查、鉴别和定量提供方法,部分解决了测定化妆品中挥发性有机溶剂时需要针对不同检测目标建立不同方法以及潜在溶剂存在备选筛查的问题。     

顶空气相色谱-质谱法同时测定蜂蜜中57种挥发性有机溶剂残留

建立了顶空气相色谱-质谱(HS-GC/MS)同时测定蜂蜜中57种挥发性有机溶剂(包括烷烃类、芳香烃类、醇类、酮类、酯类、醚类)残留量的分析方法。蜂蜜样品在密封的顶空瓶中用水溶解后,在顶空仪中于80 ℃下平衡30 min,使气-液两相达到动态平衡。采用DB-624毛细管色谱柱(60 m×0.25 mm×1.40 μm)对57种有机溶剂进行分离,GC/MS测定,外标法定量。该方法对于烷烃类、芳香烃类和醚类挥发性有机溶剂在0.005～0.2 μg、酯类0.05～2.0 μg、酮类0.5～20 μg、醇类2.5～100 μg范围内线性关系良好,相关系数均大于0.996。对于烷烃类、芳香烃类和醚类挥发性有机溶剂在1.0～20 μg/kg、酯类10～200 μg/kg、酮类100～2000 μg/kg、醇类500～10000 μg/kg添加范围内的平均添加回收率为61.0%～113.1%,相对标准偏差为1.9%～9.8%。对于烷烃类、芳香烃类和醚类挥发性有机溶剂的检出限为1.0 μg/kg、酯类10 μg/kg、酮类100 μg/kg、醇类500 μg/kg。该方法操作简单、快速,灵敏度和准确度高,适用于蜂蜜样品中多种挥发性有机溶剂残留量的同时检测。     

Ionic liquids as superior solvents for headspace gas chromatography of residual solvents with very low vapor pressure,relevant for pharmaceutical final dosage forms

1-n-Butyl-3-methylimidazolium dimethyl phosphate (BMIM DMP) was identified as the most suitable ionic liquid as solvent for the headspace gas chromatographic analysis of solvents with very low vapor pressure such as dimethylsulfoxide, N-methylpyrrolidone, sulfolane, tetralin, and ethylene glycol in a realistic matrix of commonly used excipients (carboxymethylcellulose, magnesium stearate, guar flour, and corn starch) in pharmaceutical products. Limits of quantification and limits of detection were in the low microgram per gram range. The detection of traces of sulfolane in a real sample of tablets containing the drug cefpodoxim proxetil demonstrated the applicability of the method.     

Headspace gas chromatography-flame ionization detector method for organic solvent residue analysis in dietary supplements

An analytical method has been developed for the identification and quantification of 20 organic solvent residues in dietary supplements. The method utilizes a headspace sampler interfaced with gas chromatography and flame ionization detection. With split injection (5:1) and a DB-624 column, most of the organic solvents are separated in 9 min. The method has been validated and was found to be relatively simple and fast, and it can be applied to most common organic solvent residues. With the mass detector, the method was able to identify organic solvents beyond the 20 standards tested.     

Mixed aqueous solutions as dilution media in the determination of residual solvents by static headspace gas chromatography

Static headspace (HS) sampling has been commonly used to test for volatile organic chemicals, usually referred to as residual solvents (RS) in pharmaceuticals. If the sample is not soluble in water, organic solvents are used. However, these seriously reduce the sensitivity in the determination of some RS. Here, mixed aqueous dilution media (a mixture of water and an organic solvent like dimethyl formamide, dimethyl sulfoxide or dimethyl acetamide) were studied as alternative media for static HS-gas chromatographic analysis. Although it has been known that mixed aqueous dilution media can often improve sensitivity for many RS, this study used a systematic approach to investigate phase volumes and the organic content in the HS sampling media. Reference solutions using 18 different class 1, 2 and 3 RS were evaluated. The effect of salt addition was also studied in this work. A significant increase in the peak area was observed for all RS using mixed aqueous dilution media, when compared with organic solvents alone. Matrix effects related to the mixed aqueous dilution media were also investigated and reported. Repeatability and linearity obtained with mixed aqueous dilution media were found to be similar to those observed with pure organic solvents.     

Gas chromatographic analysis of organic solvent mixtures on capillary columns of different polarity

Summary A gas chromatographic method for the analysis of organic solvents in chemical products is described. The analysis is performed by the use of a polar column, Supelcowax 10, and a non-polar column CP-Sil-5CB. Samples containing a non-volatile matrix or water were analysed by headspace analysis. The identification of the solvents in a sample, based on GC retention times on one column, is confirmed by GC of the sample on the second column. The method has been found to be suitable for the routine analysis of solvent mixtures.     

Preparation of Al2O3/TiO2 composite sol-gel fiber for headspace solid-phase microextraction of chlorinated organic solvents from urine

A new solid-phase microextraction fiber based on alumina/titania sol-gel-coated on copper wire for headspace sampling of chlorinated organic solvents (chloroform, carbon tetrachloride, trichloroethene, and tetrachloroethene) from urine samples is introduced. The influences of fiber coating composition and microextraction conditions (extraction temperature, extraction time, and ionic strength of the sample matrix) on the fiber performance were investigated. Also, the influence of temperature and time on desorption of analytes from fiber was studied. The proposed fiber has high capacity and demonstrates fast sampling of chlorinated organic solvents from urine samples with high sensitivity. The relative standard deviation (RSD, n=5) for all analytes was below 6.5%.     

Analysis of organic solvents in printing inks by headspace gas chromatography – mass spectrometry

Static headspace analysis by gas chromatography has been found to be a suitable method for the analysis of organic solvents in printing inks. Experimental conditions for the analysis have been optimized, and the accuracy and relative standard deviation of the method has been determined. The solvent content of 29 printing inks has been measured.     

Simple polymerization through oxygen at reduced volumes using oil and water

An enduring question is: what is the simplest and easiest way to obtain tailored polymers? This communication explores a robust photoiniferter polymerization with only two active ingredients that requires no prior deoxygenation and can be performed on the milliliter scale or sub-milliliter scale. Rather than leaving headspace in the polymerization vessel or scaling reactions up to fill the vessel, this approach fills the headspace of the reaction vessel with mineral oil or inert solvents. This approach can also be applied to polar monomers in aqueous media, using oil as the inert solvent, or to hydrophobic monomers with water as the inert solvent. This method removes enough ambient oxygen that the photoiniferter reaction proceeds with no deoxygenation step, and achieves high conversion and good molecular weight control in 10–20 h in both aqueous and organic solvents. Complex polymer architectures such as multiblock copolymers and gradient polymers were successfully synthesized by this approach.     

The Use of Automated Headspace Gas Chromatography for Determination of 1,1,1-Trichloroethane in Rat Blood and Brain Tissue

Abstract

1,1,1-trichloroethane in blood and brain tissue from rats which had been artificially ventilated with solvent (8000 ppm) was analysed by automated headspace gas chromatography using a fused silica capillary column. A given concentration of 1,1,1-trichloroethane in the brain could be correlated with a corresponding concentration in the blood; both the uptake and release of the solvent were quicker in blood than in brain. No volatile metabolites of the solvent were found. Automated headspace gas chromatographic analysis is a rapid and sensitive technique for the quantitative registration of volatile organic solvents, e.g. of industrial importance, in body fluids and tissues.     

Multiple headspace solid-phase microextraction for the quantitative determination of volatile organic compounds in multilayer packagings

The theory of multiple headspace solid-phase microextraction (HS-SPME) and a method based on multiple HS-SPME for the quantitative determination of volatile organic compounds (VOCs) in packaging materials is presented. The method allows the direct analysis of solid samples without using organic solvents to extract analytes. Multiple headspace solid-phase microextraction is a stepwise method proposed to eliminate the influence of the sample matrix on the quantitative analysis of solid samples by HS-SPME. Different amounts of packaging and different volumes of standard solution were studied in order to remove a substantial quantity of analytes from the headspace at each extraction and obtain the theoretical exponential decay of the peak area of the four successive extractions and, thus, the total area was calculated from these four extractions. In addition, two fibres were compared: carboxen-polydimethylsiloxane (CAR-PDMS) and divinylbenzene-carboxen-polydimethylsiloxane (DVB-CAR-PDMS), as they showed differences in the linearity of the exponential decay with the number of extractions depending on the compound. The CAR-PDMS fibre was better for the VOCs with a low molecular mass, whereas the DVB-CAR-PDMS fibre was better for the VOCs with a high molecular mass. Finally, the method was characterised in terms of linearity, detection limit and reproducibility and applied to analyse four multilayer packaging samples with different VOCs contents.     

顶空气相色谱法测定盐酸司他斯汀中6种残留溶剂

建立了顶空气相色谱法(HS-GC)测定盐酸司他斯汀中乙醚、丙酮、异丙醇、四氢呋喃、甲苯与二甲苯6种有机溶剂残留量的方法.样品用二甲基亚砜溶解,在110 ℃加热20 min,使气液平衡,采用氢火焰离子化检测器(FID),以DB-1701(60 m x 0.320 mm,1.00 μm)为分析柱,程序升温测定.在优化的气相...     

Extraction of organic compounds with room temperature ionic liquids

Room temperature ionic liquids are novel solvents with a rather specific blend of physical and solution properties that makes them of interest for applications in separation science. They are good solvents for a wide range of compounds in which they behave as polar solvents. Their physical properties of note that distinguish them from conventional organic solvents are a negligible vapor pressure, high thermal stability, and relatively high viscosity. They can form biphasic systems with water or low polarity organic solvents and gases suitable for use in liquid–liquid and gas–liquid partition systems. An analysis of partition coefficients for varied compounds in these systems allows characterization of solvent selectivity using the solvation parameter model, which together with spectroscopic studies of solvent effects on probe substances, results in a detailed picture of solvent behavior. These studies indicate that the solution properties of ionic liquids are similar to those of polar organic solvents. Practical applications of ionic liquids in sample preparation include extractive distillation, aqueous biphasic systems, liquid–liquid extraction, liquid-phase microextraction, supported liquid membrane extraction, matrix solvents for headspace analysis, and micellar extraction. The specific advantages and limitations of ionic liquids in these studies is discussed with a view to defining future uses and the need not to neglect the identification of new room temperature ionic liquids with physical and solution properties tailored to the needs of specific sample preparation techniques. The defining feature of the special nature of ionic liquids is not their solution or physical properties viewed separately but their unique combinations when taken together compared with traditional organic solvents.     

Testing the polarity and adsorptivity of nondeactivated GC capillary surfaces

Split injection of 1-pentanol headspace on to raw or treated fused silica tubing yields information on the characteristics of its surface (silanol concentration, polarity, adsorptivity). Fused silica tubing from three sources was compared. The effect of various leaching and etching procedures used for column preparation was studied, as was the stability of uncoated fused silica precolumns towards water and some organic solvents.     

顶空气相色谱法测定氟尼辛葡甲胺原料药中有机溶剂残留量

建立了氟尼辛葡甲胺原料药中乙酸乙酯、甲醇、异丙醇、乙醇和乙腈有机溶剂残留量的顶空气相色谱分析方法。以HP-FFAP色谱柱(30 m×0.32 mm×1.0 μm)为分离柱,火焰离子化检测器检测,外标法定量,并考察了顶空平衡温度、平衡时间等对残留有机溶剂测定的影响。实验结果表明,在顶空平衡温度为90 ℃、平衡时间为30 min条件下获得较好的定量结果。乙酸乙酯、甲醇、异丙醇、乙醇和乙腈的线性范围分别为0.40～7.93 mg/L (r=0.9998)、7.32～146.48 mg/L (r=0.9996)、4.53～90.61 mg/L (r=0.9999)、3.62～72.32 mg/L (r=0.9998)和2.31～46.24 mg/L (r=0.9996);平均回收率范围为95.96%～100.31%,精密度(以相对标准偏差计,n=6)为1.97%～3.28%;检出限分别为0.08、0.9、0.2、0.4和0.3 mg/L。利用该方法对实际样品氟尼辛葡甲胺原料药中有机溶剂残留量进行了检测。结果表明,该样品中含有异丙醇和乙醇,其含量分别为177.44 μg/g与69.32 μg/g。本方法快速、灵敏、准确,适用于氟尼辛葡甲胺原料药中残留溶剂的检测。     

Headspace solid phase microextraction (HSSPME) for the determination of volatile and semivolatile pollutants in soils

We have investigated the use of headspace solid phase microextraction (HSSPME) as a sample concentration and preparation technique for the analysis of volatile and semivolatile pollutants in soil samples. Soil samples were suspended in solvent and the SPME fibre suspended in the headspace above the slurry. Finally, the fibre was desorbed in the Gas Chromatograph (GC) injection port and the analysis of the samples was carried out. Since the transfer of contaminants from the soil to the SPME fibre involves four separate phases (soil-solvent-headspace and fibre coating), parameters affecting the distribution of the analytes were investigated. Using a well-aged artificially spiked garden soil, different solvents (both organic and aqueous) were used to enhance the release of the contaminants from the solid matrix to the headspace. It was found that simple addition of water is adequate for the purpose of analysing the target volatile organic chemicals (VOCs) in soil. The addition of 1 ml of water to 1 g of soil yielded maximum response. Without water addition, the target VOCs were almost not released from the matrix and a poor response was observed. The effect of headspace volume on response as well as the addition of salt were also investigated. Comparison studies between conventional static headspace (HS) at high temperature (95 degrees C) and the new technology HSSPME at room temperature ( approximately 20 degrees C) were performed. The results obtained with both techniques were in good agreement. HSSPME precision and linearity were found to be better than automated headspace method and HSSPME also produced a significant enhancement in response. The detection and quantification limits for the target VOCs in soils were in the sub-ng g(-1) level. Finally, we tried to extend the applicability of the method to the analysis of semivolatiles. For these studies, two natural soils contaminated with diesel fuel and wood preservative, as well as a standard urban dust contaminated with polyaromatic hydrocarbons (PAHs) were tested. Discrimination in the response for the heaviest compounds studied was clearly observed, due to the poor partition in the headspace and to the slow kinetics of all the processes involved in HSSPME.     

Ion-association method for the spectrophotometric determination of the antitussive drug noscapine

A simple, sensitive and fairly rapid method for the determination of noscapine is described, based on the measurement of the absorbance of the organic soluble ion-association complex formed between the noscapine monocation and a bulky counter anion. Methyl Orange, Bromothymol Blue and Bromocresol Green (BCG) were examined as counter ions. The effect of few solvents, the counter-ion concentration and pH on the extraction were also investigated. The most suitable system was based on BCG (pH 3.0) with chloroform as the extraction solvent. The use of the other counter ions, in conjunction with their respective solvents, was found to be less sensitive. The BCG system exhibits negligible or no interference when used for the determination of 38 ppm of noscapine in the presence of several drug excipients, thus lending itself as a possible procedure for the determination of this alkaloid in pharmaceutical preparations.     

Unknown residual solvents identification in drug products by headspace solid phase microextraction gas chromatography-mass spectrometry

Summary A sensitive headspace SPME method for the extraction of residual solvents from pharmaceutical products has been developed and optimized. It was found that minimizing sample and headspace volume has a beneficial effect on extraction efficiency. At the same time the method reproducibility was seriously affected by reducing sample and headspace volume. The added air volume was not found to have any significant influence on method sensitivity. The method showed reproducibilities of less than 10% and detection limits as low as 1 ppb for benzene and dichloromethane. The headspace SPME method is around 1000 times more sensitive than static headspace. The optimized parameters were headspace volume 1.5 mL, sample volume 10 μL, and extraction time 30 min. The method was successfully applied to the identification of unknown residual solvents in three different proprietary active drug substances and was successfully applied to the confirmation of the presence of benzene in a proprietary drug substance. Presented at Balaton Symposium '01 on High-Performance Separation Methods, Siófok, Hungary, September 2–4, 2001