Determination of Polychlorinated Biphenyls and Chlorinated Pesticides in Environmental Biological Samples Using Focused Microwave-assisted Extraction

Abstract

Organochlorine compounds such as polychlorinated biphenyls (PCBs) and chlorinated pesticides have been analysed in environmental biological samples using focused microwave-assisted extraction (FMW). The analytical procedure is presented and the results for two Standard Reference Materials, a cod liver oil and a freeze-dried mussel tissue, are reported. The average recoveries for the sum of the PCBs are between 93% and 106%, and for the sum of the chlorinated pesticides are between 109 to 115% for all the certified compounds analysed. The developped analytical procedure is highly reproducible with an average standard deviation of 8% for the sum of the PCBs and 9.7% for the sum of the chlorinated pesticides in the two matrices.     

生物样品中短链脂肪酸的提取与测定

综述了生物样品(主要为粪便、尿液、血液和培养液)中短链脂肪酸的提取与测定方法,讨论了各种样品提取方法的优缺点,并比较了气相色谱、高效液相色谱和毛细管电泳分离检测的优点和局限性。引用文献63篇。     

Determination of Methadone in Biological Samples Using Liquid Phase Microextraction with Back Extraction Combined with LC

Liquid phase microextraction with back extraction (LPME-BE) combined with liquid chromatography-ultra violet (LC-UV) was applied for the extraction and determination of methadone in biological fluids. At the optimized conditions, an enrichment factor of 386 and detection limit (LOD) of 0.2 μg L^?1 were obtained. The calibration curve was linear (r ² = 0.989) in the concentration range of 0.6–1,000 μg L^?1. Within-day relative standard deviation RSD (S/N = 3) and between-day RSD were 2.7 and 5.9%, respectively. The feasibility of the proposed method was evaluated by extraction and determination of methadone in plasma and urine samples and satisfactory results were obtained.     

硝普钠显色测定药物样品中甲巯咪唑

在溶液中NaOH浓度为6.7×10-3mol/L及0℃(冰水浴)条件下,反应时间为30 min,硝普钠与甲巯咪唑生成化学计量比为1碱性条件下硝普钠与甲巯咪唑反应生成化学计量比为1∶1的绿色产物,其最大吸收波长为610 nm。甲巯咪唑在4.8~48 mg/L浓度范围内与吸光度呈良好线性关系,线性回归方程为A=-0.0617 0.01329C(mg/L),相关系数r=0.9991;检出限为0.47 mg/L;相对标准偏差RSD=0.2%。本法成功用于测定片剂药品中甲巯咪唑的含量,平均回收率大于97.2%。     

A PVC Membrane Sensor for Potentiometric Determination of Atorvastatin in Biological Samples and Pharmaceutical Preparations

The present article reports for the first time the use of Aliquat 336S‐atorvastatin as an electroactive material in a poly(vinyl chloride) matrix membrane sensor plasticized with ortho‐nitrophenyl‐octylether (o‐NPOE) or dioctylphthalate (DOP) for determination of atorvastatin in biological samples (human plasma) and in pharmaceutical preparations. The sensor shows fast, stable and reproducible response over the concentration range of 1.0×10^?7–1.0×10^?2 mol L^?1 atorvastatin with anionic slopes of 60.94±0.2 and 58.22±0.2 and pH range of 5.0–9.0 for o‐NPOE and DOP plasticized based membrane sensors, respectively. The response time of the sensor is stable and fast (10 s). Results were achieved with average recoveries of 99.5 % and 99.3 % and mean standard deviations of ±1.1 % and ±1.4 % for o‐NPOE and DOP plasticized based membrane sensors, respectively. The sensor exhibits high selectivity towards atorvastatin in the presence of many anions, drug excipients and diluents. Validation of the method according to the quality assurance standards shows suitability of the proposed sensors for use in the quality control assessment of the drug.     

Solid Phase Extraction and Determination of Lead in Water Samples Using Silica Gel Homogeneously Modified by Thiosalicylic Acid

Abstract

Silica gel was modified by thiosalicylic acid via homogeneous routes to obtain immobilized silica gel sorbent (TSA‐immobilized silica gel). This new sorbent was characterized using variety of physical chemistry techniques including, high resolution solid state ¹³C and ²⁹Si CP/MAS NMR, X‐ray photoelectron spectroscopy (XPS), thermal analysis (TGA and DTA), elemental analysis, and BET surface analysis as well as infrared spectroscopy (FTIR). New support was used for the selective extraction and concentration of lead ions by silica gel modified with thiosalicylic acid, as a highly selective and stable reagent, from aquatic samples and its determination with FAAS. Lead ions can be desorbed with 4 mol dm^?3 HNO₃. The sorption capacity for lead ions are found in the range of 64.40 to 69.90 µmol g^?1 of chelating matrix. Tolerance limits for electrolytes and some trace metals in the sorption of lead is reported. Preconcentration factor was found as 150 for Pb(II). The lead in drinking water, mineral water, tap water, and fruit juice was quantitatively recovered with a relative standard deviation lower than 1.50%. A detection limit of the method for lead ions was found as 3.7 µg l^?1.     

Novel Potentiometric Sensors for Determination of Melatonin and Oxomemazine in Biological Samples and in Pharmaceutical Formulations

Simple, selective and accurate sensors were developed for the determination of melatonin and oxomemazine in biological samples (urine) and in pharmaceutical preparations. Potentiometric measurements were based on bismus tetraiodate‐drug ion‐pair as novel electroactive materials incorporating a plasticized PVC membrane with o‐nitrophenyl octyl ether or dioctyl phthalate. Each sensor was conditioned for at least two days in 0.1 M drug solution before use. It exhibited fast and stable Nernstian response for melatonin and oxomemazine over the concentration range of 1.0×10^?6–1.0×10^?2 M and 1.0×10^?5–1.0×10^?2 M, pH range of 3.0–6.5 and 3.5–6.0 for melatonin and oxomemazine sensors, respectively. Results with an average recovery not more than 101 % and a mean standard deviation less than 1.0 % of the nominal were obtained for the four sensors. The sensors showed reasonable selectivity towards investigated drugs in presence of many cations.     

食品及生物样品中痕量草酸的荧光动力学法测定

拟定了一个荧光动力学测定痕量草酸根的新方法。在硫酸介质中，草酸催化重铬酸钾氧化罗丹明６Ｇ使其荧光猝灭。方法线性范围为０．８－１４．０ｍｇ／Ｌ，直接用于菠菜，人尿中草酸根的测定，获得满意结果。     

固相萃取-气相色谱法测定水中毒死蜱

水样中的毒死蜱经全自动固相萃取仪萃取、乙酸乙酯洗脱后,用气相色谱火焰光度检测法测定,以保留时间定性,外标法定量．结果表明：选用ENVI-18小柱萃取、乙酸乙酯洗脱,在2mL／min的过水速率下取得了良好的回收率．方法的线性范围为0．25～4．0mg／L．r为0．9998,回收率为88．6％～100．6％,相对标准偏差为2．58％～7．34％,最低定量浓度为2．5μg／L．本方法快速、灵敏、准确,并能够很好的排除干扰,可以满足水中痕量毒死蜱的测定．     

Synergistic Extraction and Atomic Absorption Spectrometric Determination of Managanese in Environmental Samples Using M-p-Aminophenyl-2-Furylacrylohydroxamic Acid and Trioctylmethylammonium Cation

Abstract

Fifteen new hydroxamic acids were explored in conjunction with trioctyimethylammonium cation for the extractive separation of manganese into MIBK from the anions and cations commonly associated with the metal in environmental samples. The most rapid extraction with the maximum selectivity and sensitivity for the atomic absorption spectrometric determination of the metal in the MIBK extract was achieved with N-p-aminophenyl-2-furylacrylohydroxamic acid. The method enabled the determination of manganese at sub-ppb levels and was applied in the analysis of coal, manganese ore, plant tissue, animal tissue and natural waters.     

Disposable Stochastic Dot Sensors for the Assay of Ascorbic Acid in Pharmaceutical Samples,Beverages, and Biological Fluids

Eight disposable stochastic dot sensors based on porphyrins and modified diamond or carbon pastes were employed for the assay of ascorbic acid in pharmaceutical, beverages, and biological samples. The advantage of using such sensors for the assay of ascorbic acid is the possibility of qualitative and quantitative assay of ascorbic acid in one run of the experiment. The covered linear concentration range for these sensors was between 10^?14 and 10^?5 mol/L with high sensitivities. The proposed dot sensors were used reliably (RSD < 1%) for the assay of ascorbic acid from different samples for more than 6 months, with a recovery higher than 92.00%.     

Diorganotin(IV) Complexes with Monohydrate Disodium Salt of Iminodiacetic Acid: Synthesis,Characterization, Crystal Structure and Biological Activities

Diorganotin(IV) derivatives have been synthesized by the reaction of R₂SnL₂ (R=n‐Bu 1 , Ph 2 ) with monohydrate disodium salt of iminodiacetic acid ( Na₂L ) in 1 : 1 M/L ratio under reflux conditions. The compounds have been characterized by FT‐IR, NMR (¹H and ¹³C) spectoscopy, electron ionization mass spectrometry (EIMS), thermogravimetric analyses (TGA) and single crystal XRD. FTIR data indicates a mono‐dentate binding mode of the carboxylic acid group as well as participation of the amino nitrogen and aqua oxygen in coordination with organotin(IV) moieties. NMR data demonstrates a tetra‐coordinated environment around tin(IV) in solution. Mass spectrometric and thermogravimetric analyses verify the close similarities between the molecular structures of both complexes. The thermal stability of diphenyltin(IV) derivative ( 2 ) was found slightly higher than that of the free ligand ( Na₂L ). Single crystal X‐ray analysis of the complex 1 have shown a hexa‐coordinated geometry around Sn(IV) with trans configuration. There are evidences for the existence of intermolecular hydrogen bonding in the structure of the complexes. The products displayed significant antibacterial and antifungal activities in contrast to the biologically inactive ligand precursor. However, the hemolytic cytoxicity of the complexes was comparatively high than the free ligand.     

Microwave Single Vessel Acid-Vapor Extraction: Effect of Experimental Parameters on Co and Fe Determination in Biological Samples

Characteristic parameters of a single vessel procedure were investigated for Co and Fe determination in biological samples using nitric acid-vapor extraction under atmospheric pressure. A laboratory-made PTFE support vessel suitable for four cups containing the samples was adapted to fit on the microwave glass vessel. Biological samples (30mg) were weighed directly into these PTFE cups and exposed to nitric acid vapor stemming from 15mL concentrated HNO₃ placed in the bottom of the glass vessel. Sample cups were positioned at 50, 80, 110, and 140mm from the support base. We evaluated the temperature, acidity, and residual carbon content of each sample cup, i.e. parameters that could influence the efficiency of vapor-phase acid digestion. The influence of sample particle size on digestion efficiency was also considered. It was demonstrated that temperature was the main parameter for efficient recovery of both Co and Fe in biological samples, and higher temperatures allowed lower residual carbon contents.     

聚乙烯吡咯烷酮增敏荧光光度法测定生物样品中痕量铅

研究了聚乙烯吡咯烷酮对桑色素和铅（Ⅱ）络合反应的增敏作用，发现ＰＨ３．４３时Ｐｂ－ｍｏｒｉｎ－ＰＶＰ三元体系在４３５ｎｍ激发下，４４４ｎｍ处有强荧光发射，提出了荧光光度法测定痕量Ｐｂ的新方法，其线性范围为０－２４０μｇ／Ｌ，对空白１１次测定ＲＳＤ为３．５％，检出限为２．１＊１０＾－２ｍｇ／Ｌ。     

微波加热快速测定腐植酸总量

利用微波加热技术，在密闭容器内通过压力浸提、消解试样、能大大加快分析速度，本实验测定了不同煤样中的腐植酸总量，讨论了功率、时间、酸度等因素对分析结果的影响，并与标准方法相对照，用ｔ－检验法及Ｆ－检验法检验，没有明显差异，结果令人满意，该法具有省时、省力、经济、不污染环境，宜于批量分析，便于普及推广等优点。     

磁固相萃取/气相色谱一质谱法分析水样中的16种邻苯二甲酸酯类化合物

合成了一种由Fe3 O4磁性纳米粒子(MNPs)和多壁碳纳米管(MWCNTs)组成的复合纳米材料,用于水样中16种邻苯二甲酸酯类化合物(PAEs)的磁固相萃取(MSPE),并结合气相色谱-质谱(GC - MS)法进行定量分析.合成的纳米材料用傅立叶变换红外光谱表征.为提高萃取效率,优化了解析溶剂的种类和用量、解析时间、...     

Separation and Determination of Amitriptyline and Nortriptyline in Biological Samples Using Single-Drop Microextraction with GC

The combination of liquid phase microextraction (LPME) based on a single drop and gas chromatography flame ionization detector (GC-FID) was used for separation and determination of amitriptyline and nortriptyline in human plasma and urine samples. The sample solution was kept alkaline (pH 12), then a microdrop of organic solvent (isooctane) was suspended in the donor solution; after extraction, the organic microdrop was injected into the GC-FID. Experimental LPME conditions were optimized. Finally, the enrichment factors (89.5?C139.0), the relative standard deviation (RSD%, n = 5) 1.1?C8.5, linearity ranges (0.05?C20 ??g mL^?1), and the limits of detections (0.01, 0.02 ??g mL^?1) for selected drugs were evaluated.     

A Glassy Carbon Electrode Modified with Multiwalled Carbon Nanotube/Chitosan Composite as a New Sensor for Simultaneous Determination of Acetaminophen and Mefenamic Acid in Pharmaceutical Preparations and Biological Samples

A new chemically modified electrode is constructed based on multiwalled carbon nanotube/chitosan modified glassy carbon electrode (MWCNTs‐CHT/GCE) for simultaneous determination of acetaminophen (ACT) and mefenamic acid (MEF) in aqueous buffered media. The measurements were carried out by application of differential pulse voltammetry (DPV), cyclic voltammetry (CV) and chronoamperometry (CA) methods. Application of DPV method showed that the linear relationship between oxidation peak current and concentration of ACT and MEF were 1 μM to 145 μM, and 4 μM to 200 μM, respectively. The analytical performance of this sensor has been evaluated for detection of ACT and MEF in human serum, human urine and a pharmaceutical preparation with satisfactory results.