化学发光法测定尿液中8羟-基脱氧鸟苷

利用8-羟基脱氧鸟苷（8-OHdG）在酸性邻菲咯啉（Phen）-Cu化学发光体系中发光信号强的特点,建立了一种测定尿样中8-OHdG含量的方法。本方法的线性范围为1.67—333.33μg/L,检出限（S/N=3）为0.83μg/L。对167.00μg/L的8-OHdG平行测定11次,其相对标准偏差为1.2%。该法用于尿液中8-OHdG的测定,方法简便、灵敏、快速,分析结果令人满意。     

正交试验优选老鹳草中没食子酸的提取工艺

以没食子酸含量和出膏率的综合评分为指标,以溶剂用量、提取时间和提取次数为考察因素,采用正交试验优选老鹳草中没食子酸的提取工艺。结果表明,最佳提取工艺为8倍量水、回流提取3次,每次60m in。该工艺稳定可行,可作为老鹳草中没食子酸的提取方法。     

微波辅助萃取应用研究进展

近年来关于微波辅助萃取(MAE)与其他各种样品前处理技术的结合使用,以及与多种检测技术在线联用的研究越来越多,此外离子液体等新型绿色溶剂作为萃取剂在MAE中的应用也开始得到广泛关注.本文综述了近几年微波辅助萃取在环境、天然产物提取、食品和药物分析领域的应用情况,并对其将来的发展进行了展望.     

Extraction of Copper(II) from Aqueous Thiocyanate Solutions into Chloroform and Subsequent Spectrophotometric Determination

Abstract

Traces of copper(II) can be quantitatively extracted from aqueous thiocyanate solutions into 2-benzoylpyridine-2-pyridyl-hydrazone (BPPH) or 2,2′-dipyridyl-2-pyridylhydrazone (DPPH) chloroform solution. Optimal conditions given for the extraction are based on a critical study of the relevant factors such as the effect of the pH, thiocyanate and reagent concentration. Very small amounts of copper can be recovered from large sample volumes and determined directly.     

Separation of Tron(Iii) By Extraction Chromatography With Aliquat 3365 From Citrate Solution

Abstract

A rapid method is proposed for separation of iron(III) with Aliquat 336S as the stationary phase coated on silica gel column with citric acid buffered at pH 4,5 as mobile phase. the extracted iron is stripped from the column with different mineral acids and determined spectrophotracally as its complex with 1,10-phenanthroline, Iron was separated from chromium, molybdenum, titanium and nickel which are generally associated in steel samples. Similar separations of iron from lead, zinc, cadmium, bismuth and cobalt have significance in environmental sample analysis. the method is extended for analysis of iron from samples of sediment and sea-water.     

Optimization of the Extraction and Analysis of Natural Androgen Steroids and Their Metabolites in Urine by GC/MS and GC/FID

A multiresidue method was developed for screening, quantification, and confirmation of nine natural androgen steroids and their metabolites in urine. Steroids were first extracted from urine by solid phase extraction, enzymatically deglucuronated, re-extracted using a liquid/liquid extraction for purification, and finally acetylated for GC/MS and GC/FID analysis. Each step of sample preparation, as well as analysis, was optimized: solid phase extraction, liquid/ liquid extraction, and derivatization reaction … Therefore, a rugged sample preparation procedure was developed leading to extracts of sufficient purity (recoveries >66% and few matrix compounds). The whole methodology allowed reliable detection and quantification of the nine steroids at low concentration levels. Linearity and repeatability were established and were found to be satisfactory (R² > 0.996, RSD < 11%). Finally, the method was applied to quantify compounds of interest in real samples collected from healthy volunteers and patients treated with 4-androstenedione or dehydroepiandrosterone.     

Determination of Pyridostigmine in Mammalian Plasma: Addressing Current Problems

Abstract

The variable data for pyridostigmine levels reported in human plasma would indicate procedural and/or analytical problems. Consequently an effort was made to establish a precise and sensitive method which could be applied to the quantitation of pyridostigmine in plasma of human as well as other mammalian species. In this method the effect of various types of anticoagulants, the efficacy and precision of the isolation cartridge, the stability of the drug in blood, and the effect of cryogenic storage on the isolation and quantitation of both drug and internal standard were examined. Data on spiked human, guinea pig, dog, and rat plasma at nanogram level of pyridostigmine were presented. Variable concentrations of mobile phase, ranging from 20–27% acetonitrile in water, were used to minimize interfering peaks present in blank samples. Limits of sensitivity in ng/ml (CV) were: human, 2.5 (12.5%), guinea pig, 5.0 (4.5%), dog, 5.0 (2.7%), and rat, 5.0 (7.2%).     

Optimization of Extraction Conditions for Flavonoid Composition and Antioxidant Activity of Radix Scutellariae

Microwave, ultrasonic, and reflux extraction were compared to provide an optimized method for flavonoids from Radix Scutellariae including the antioxidant activity of the extracts. The antioxidant activities of the extracts were evaluated by 2,2-diphenyl-1-picrylhydrazyl and oxygen radical absorbance capacity assays. Baicalin, wogonoside, baicalein, wogonin, and oroxylin A were quantified using ultra-high performance liquid chromatography. For microwave extraction, with a ten minutes treatment, the extraction efficiencies of the analytes were higher than treatments by refluxing for 180 minutes and sonication for sixty minutes. In addition, the antioxidant activity of the microwave extracts was slightly higher than the extracts obtained by the other methods. Microwave extraction conditions were further optimized by a single-factor experiment and the optimum conditions were 50 percent ethanol–water (volume by volume), an extraction temperature of 100 degrees celsius, an extraction time of ten minutes, and a sample to solvent ratio of 1:50. This study combines extraction, phytochemistry, and bioactivity to screen the most efficient extraction procedure for flavonoids from Radix Scutellariae.     

Simultaneous Determination of Trace Metals in Saudi Arabian Crude Oil Products by Inductively Coupled Plasma Mass Spectrometry (Icp/Ms)

Abstract

The inductively coupled plasma in combination with a mass spectrometer (ICP/MS) has been used for the determination of metals in different Saudi Arabian crude oils (Arab Berri, Arab heavy, Arab medium and Arab light). A previously investigated extraction method has been applied in the determination of metals in oil to the sub ppm level.     

Environmental Analysis of Thorium (IV) by Extractive Separation with N-p-Methoxyphenyl-2-furylacrylohydroxamic Acid and Spectrophotometric Determination with 4-(2-Pyridylazo) Resorcinol

Abstract

Thorium (IV) was separated from several anions and cations commonly associated with it in environmental samples by liquid-liquid extraction with N-p-methoxyphenyl-2-furylacrylohydroxamic acid (MFHA) into chloroform at pH 3.6–5.5. The metal was then back-extracted into aqueous media containing 1.8–2.2 M HCl and determined spectrophotometricall) at 500 nm (? = 3.9 × 10⁴ 1 mol^?1 cm^?1) with 4-(2-pyridylazo) resorcinol [PAR]. The method was successfully applied to the analysis of thorium in coal fly ash, monazite, uranium-thorium ore, animal tissue, plant tissue, and natural waters. MFHA and PAR were chosen from thirteen hydroxamic acids and nine pyridylazo reagents, as the reagent combination that provided the maximum selectivity and sensitivity.