高效液相色谱法测定卷烟醋酸纤维滤棒中甲醛、乙醛和丙酮的含量

建立了高效液相色谱法同时测定卷烟醋酸纤维滤棒中甲醛、乙醛和丙酮含量的方法,采用Acclaim(R)Explosive E2 C18色谱柱,流动相为乙腈/水梯度洗脱,流速为0.5 mL/min,检测波长为352 nm,对甲醛、乙醛和丙酮的分析取得满意的效果.甲醛、乙醛、丙酮的回收率分别为95.3％～105.6％、86.1...     

Evaluation of Monolithic Columns for Determination of Formaldehyde and Acetaldehyde in Sugar Cane Spirits by High-Performance Liquid Chromatography

Abstract

High-Performance Liquid Chromatography (HPLC) conditions are described for separation of 2,4-dinitrophenylhydrazone (2,4-DNPH) derivatives of carbonyl compounds in a 10 cm long C₁₈ reversed phase monolithic column. Using a linear gradient from 40 to 77% acetonitrile (acetonitrile-water system), the separation was achieved in about 10 min—a time significantly shorter than that obtained with a packed particles column. The method was applied for determination of formaldehyde and acetaldehyde in Brazilian sugar cane spirits. The linear dynamic range was between 30 and 600 µg L^?1, and the detection limits were 8 and 4 µg L^?1 for formaldehyde and acetaldehyde, respectively.     

HPLC Determination of Amino And Carbonyl Compounds with Dabsyl Chloride and Dabsyl Hydrazine

The new chromophoric reagent, 4-dimethylaminoazobenzene-4′-sulfonyl chloride (dabsyl chloride) was synthesized by reaction of sodium 4-dimethylaminoazobenzene 4′-sulfonate with phosphorus pentachloride. Dabsyl chloride reacted rapidly with all amino acids, aliphatic amines, and polyamines to form the corresponding dabsyl derivatives. The dabsyl amino acids (10^?11 mol) were visualized on thin layer plates and found to be photo-stable. During the last 12 years, in combination with HPLC, this newly developed labeling reagent has been shown to be very promising for microdetermination of amino acids, aliphatic amines and polyamines. Recently, another new chromophoric reagent, dabsylhydrazine, was synthesized from the reaction of dabsyl chloride with hydrazine. This reagent reacted readily with monosaccharides and carbonyl compounds to form the corresponding chromophoric dabsylhydrazones with strong absorbance at 425 nm. The application of this new reagent in HPLC analysis of monosaccharides was discribed. By use of Nova-PAK C₁₈ reverse-phase column and a concave gradient system of water and acetonitrile as eluent, the detection limits of monosaccharides in the range of 10 pmol have been reached.     

胶束电动毛细管色谱法测定大气中的甲醛、乙醛和丙酮

用胶束电动毛细管色谱法同时测定了大气污染物甲醛、乙醛和丙酮。样品经２,４－二硝基苯肼衍生。采用４７ｃｍ（到检测窗口４０ｃｍ）×５０μｍｉ．ｄ．毛细管柱,以５０ｍｍｏｌ／Ｌ十二烷基硫酸钠－２０ｍｍｏｌ／Ｌ四硼酸钠溶液（ｐＨ９．００）为操作缓冲溶液,电压３０ｋＶ,检测波长２１４ｎｍ,７．５ｍｉｎ内甲醛、乙醛和丙酮的２,４－二硝基苯腙衍生物可获得良好的分离。用峰面积定量,线性范围为０．０１～０．５ｇ／Ｌ,最小检出浓度均为２ｍｇ／Ｌ,变异系数在８．７％以内。     

高效液相色谱法测定卷烟粘合剂中甲醛、乙醛的含量

提出了预衍生化高效液相色谱法测定卷烟粘合剂中甲醛、乙醛含量的方法。卷烟粘合剂中醛经纯净水提取,离心机离心后分取部分上层清液,与2,4-二硝基苯肼衍生反应,生成的甲醛和乙醛的2,4-二硝基苯腙,用C18柱进行分离,用乙腈与水的混合物作流动相。在358nm紫外波长下检测,用醛衍生物配制标准定量。甲醛和乙醛在0.10～10.0mg·mL-1范围内呈线性。甲醛加标回收率在98.3%～118.9%之间,乙醛加标回收率在79.2%～89.2%之间,相对标准偏差(n=5)均小于5%。     

Application of the Combustion Method in a Closed Flask to the Lead Determination in Atmospheric Aerosols

Abstract

The destruction of the filter for metal determination in atmospheric aerosols is an important step in the analysis. Nowadays the decomposition of this kind of sample has not been completely solved, so it is interesting to study new methods for filter sample attack. In the present work the application of the combustion method in a closed flask for mixed cellulose esters filter decomposition for lead determination is proposed. For this purpose optimum operating conditions as stopper flask design, sample size, flask volume, shaking time and volume and concentration of absorbing solution are established, and accuracy and precision of the proposed method using AAS for the measurements is given. The results obtained by the closed flask combustion are compared with those found by wet attack with HNO₃. The method proposed is rapid, has low reagent contamination and no loss of lead by volatilization or by amalgamation occurs. This method shows an accuracy and a precision in good agreement with the standard method.     

Determination Of Chlorpromazine And Its Sulfoxide And 7-Hydroxy Metabolites By Ion-Pair High Pressure Liquid Chromatography

Abstract

An ion-pair HPLC approach with ordinary silica has been applied, with detection by ultraviolet absorption, to the assay of plasma for chlorpromazine and its sulfoxide on the one hand, and for 7-hydroxychlorpromazine (an active metabolite) on the other hand. The respective sample-preparation procedures entail extraction of the plasma with heptane at strongly alkaline pH, or else with diethyl ether at a less alkaline pH and with ensuing back-extraction and re-extraction. For each of the compounds, levels as low as 10 ng. ml^?1 are measurable. The conditions adopted are such that specificity and reproducibility are satisfactory although chlorpromazine and its various metabolites, especially 7-hydroxychlorpromazine, are chemically unstable and, moreover, are readily lost onto glass. With the unorthodox separation system adopted, adsorption rather than partition appears to be the dominant mechanism.     

Interface-Free Coupling Of Hplc And Atomic Spectrometry For Trace Metal Speciation By Using A High Performance Flow And Nebulization System

Abstract

The on-line coupling of HPLC with flame-AAS using a HPF/HHPN system (high performance flow/hydraulic high pressure nebulization) is described. The proposed system is used for speciation of trace metals. High molecular weight species (protein-bound metals) as well as low molecular weight ones (organic acid complexes of metals) are separated and specifically detected. Problems arising from the flow-rate and composition of the mobile phase are discussed and it is shown that these problems can be solved by optimizing the HHP-nebulizer.