在线预浓缩FIA比浊法测定水中微量硫酸根

在线预浓缩ＦＩＡ比浊法测定水中微量硫酸根李俊锋，郭如江，赵楠，李绍民（长春地质学院应用化学系长春１３００２６）（吉林大学环境科学系）关键词在线预浓缩，ＦＩＡ，硫酸根流动注射比浊法测定微量硫酸根已有报道［１，２］，由于干扰组分的作用使得前处理操作麻烦，...     

Optimization of An On-Line Precolumn Preconcentration Method for the Determination of Polycyclic Aromatic Hydrocarbons (PAHs) in Water Samples (River and Sea Water)

Abstract

A new on-line precolumn preconcentration method for the determination of EPA priority pollutants (PAHs) in river and sea water has been developed. The retention time for each PAH in the precolumn has been determined for several percentages of organic solvent (acetonitrile) in the sample. This is very important because recoveries show a great dependence on this parameter.

The proposed procedure, combined with HPLC and spectrofluorimetric detection, reaches very low detection limits (subnanograms per liter) and it has been applied to river and sea water samples with good results.     

Development of an FI-ICP Method for On-Line Preconcentration and Determination of Platinum

This paper presents a new simple and rapid procedure for the preconcentration and determination of platinum. It is based on the adsorption of the metal ion and preconcentration on a micro-column (3cm×3mm) placed in the injection valve of a flow injection (FI) manifold and packed with 1,5-bis[(2-pyridyl)-3-sulphophenyl-methylene]thiocarbonohydrazide (PSTH) immobilised on an anion-exchange resin (Dowex 1X8-200). The metal was eluted from the column using a solution of 2M HNO₃. Various parameters and chemical variables affecting the preconcentration and determination of this metal by ICP-AES were evaluated. Five variables (sample flow rate, eluent flow rate, nebulizer flow rate, buffer concentration and mixing coil length) were considered as factors in the optimisation process. Interactions between analytical factors, and their optimal levels were investigated using two level factorial and central matrix designs. The optimum conditions established were applied to the determination of platinum by flow injection inductively coupled plasma atomic emission spectrometry (FI-ICP-AES). The method has a linear calibration range of 25 to at least 200ngmL^–1 with a detection limit of 7.4ngmL^–1 (S/N=3) and a throughput of 10 samples h^–1 using 5min. preconcentration time. The precision of the method (RSD) was 3.06% ngmL^–1 at the 50ngmL^–1 level of Pt(IV) and 2.93% at the 150ngmL^–1 level. The accuracy of the method was examined by determining the analyte content in spiked waters and by analysing an automobile catalyst standard reference material. The results show good agreement with the certified value and sufficiently high recoveries.     

流动注射在线分离富集光度法测定铜

本文提出痕量铜的在线流动注射离子交换树脂分离富集的吸光光度测定方法，以显色液作为淋洗液，直接洗脱Ｄ４０１螯合树脂上富集的铜，与此同时显色剂与铜（Ⅱ）生成有色络合物，在６３２ｎｍ处测定铜。     

流动注射在线分离浓集技术在原子吸收光谱分析中的应用

对流动注射在线分离浓度与原子吸收光谱连用技术及其应用作了综述。引用文献８６篇。     

Trends in Preconcentration Procedures for Metal Determination Using Atomic Spectrometry Techniques

 Methods for metal preconcentration are often described in the literature. However, purposes are often different, depending on whether the methods are applied in environmental, clinical or technological fields. The respective method needs to be efficient, give high sensitivity, and ideally also is selective which is useful when used in combination with atomic spectroscopy. This review presents the actual tendencies in metal preconcentration using techniques such as Flame Atomic Absorption Spectrometry (FAAS), Electrothermal Atomic Absorption Spectrometry (ETAAS), Hydride Generation Atomic Absorption Spectrometry (HGAAS), Inductively Coupled Plasma Optical Emission Spectrometry (ICP OES) and Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Procedures based on related to electrochemical, coprecipitation/precipitation, liquid–liquid and solid–liquid extraction and atom trapping mechanisms are presented. Correspondence: Department of Analytical Chemistry, Universidade Estadual de Campinas – UNICAMP, P.O. Box 6154, 13083-970 Campinas, Brazil. e-mail: zezzi@iqm.unicamp.br Received December 20, 2001; accepted October 11, 2002     

Kinetic Spectrophotometric Determination of Total Iron in Natural Water by Flow Injection Analysis Using On-Line Preconcentration

A new flow injection catalytic spectrophotometric method for on-line preconcentration and determination of total iron in natural water is described. The method is based on a combination of iron-catalyzed oxidation of diaminoditolyl by potassium bromate and the use of on-line preconcentration of iron onto 8-hydroxy-quinoline immobilized on silica gel. The corresponding calibration graph is linear over the range of 2.0–110ngmL^–1 for Fe(III) using a time-based technique for 5min preconcentration. The relative standard deviation of 11 measurements of 60ngmL^–1 Fe(III) was 0.67%. The method was applied to the determination of iron in natural water. The results obtained by the proposed method were compared with those obtained by ICP-AES. The t-test showed no significant differences between the two methods at a confidence level of 95%.     

Automated Determination of Ammonia in Natural Freshwaters Using Salicylate-Hexacyanoferrate-Dichloroisocyanurate System

Abstract

An automated method for the determination of ammonia in natural freshwaters was developed with the use of salicylate-hexacyanoferrate-dichloroisocyanurate system. Sodium salicylate is easy to handle and does not produce o-chlorophenol. The use of sodium dichloroisocyanurate as a chlorine donater excludes frequent standarization of chlorine content in sodium hypochlorite solution. Sensitivity in the present method is comparable with that in manual phenol method. The present study suggests that automated salicylate and phenol methods with the need of heating of more than 50°C may not determine the real concentration of ammonia due to the release of ammonia from free amino acids in natural waters.     

流动注射在线预浓集－火焰原子吸收光谱法测定葡萄酒中微量铅

流动注射在线预浓集－火焰原子吸收光谱法测定葡萄酒中微量铅孙晓娟（江苏石油化工学院应用化学系，常州，２１３０１６）Ｂ．ＷｅｌｚＭ．Ｓｐｅｒｌｉｎｇ（Ｐ－Ｅ有限公司，Ｄ－８８６６２　于伯林根，德国）关键词铅，葡萄酒，微波消解，流动注射在线预浓集，火焰原子...     

Determination of Silver with On-Line Preconcentration Using Dithiozone Chelate and Carbon Nanotubes for Preconcentration with Detection by Flame Atomic Absorption Spectrometry

A novel flow injection system incorporating a micro-column packed with carbon nanotubes (CNTs) as an adsorbent has been applied to the on-line preconcentration of trace silver with detection by flame atomic absorption spectrometry. Silver is first chelated by dithizone (H₂Dz), then retained on the CNTs surface and afterward quantitatively eluted by methanol. Influencing parameters, including the concentration of reaction reagent, enrichment variables, and elution variables were investigated. The adsorption mechanisms of Ag-H₂Dz chelate retained onto the CNTs surface have also been studied. By loading 6.9 mL sample solution, a linear calibration graph is obtained within the range of 3–120 µg L^?1 with R of 0.9996, and a detection limit (3σ) of 0.8 µg L^?1 is achieved, along with a precision of 1.6% R.S.D. at the 30 µg L^?1 level (n = 7). The dynamic sorption capacity of CNTs for silver is 122 mg g^?1. The procedure is demonstrated by measurement of spike recovery in a series of water samples, giving rise to spike recoveries in the range of 96.8–99.7%.     

高效液相色谱梯度洗脱中弱溶剂的在线净化

利用一个在线净化预柱减少了高压梯度洗脱中由于试剂纯度不够造成的基线噪音。预柱的位置在溶剂泵Ａ和流动相混合器之间,由一个六通阀来控制。在线净化结果良好,有效地除去了空白梯度色谱图中的杂质峰,提高了梯度洗脱的分离重现性。该方法对开展梯度洗脱有实用价值。     

毛细管电泳中样品的在线富集

由于毛细管进样体积小以及在柱检测光程短,极大地限制了毛细管电泳检测灵敏度的提高.为了提高毛细管电泳的检测灵敏度,多种样品富集的方法得以发展.本文对近年来毛细管电泳的样品预富集方法与应用作一简明的综述。     

流动注射离子交换预浓集火焰原子吸收光谱法直接测定人尿中痕量镉

应用高效的流动注射在线离子交换预浓集火焰原子吸收光谱测定系统直接测定了人尿中痕量镉。选择２００μＬ锥形离子交换柱，内装多孔玻璃固定化的８－羟基喹啉离子交换剂，在ｐＨ９条件下样品流速为３．５ｍＬ／ｍｉｎ，４０ｓ装样，用２ｍｏｌ／ＬＨＣｌ洗脱，在分析速度为６０样／ｈ，获得３０倍的富集倍率。检出限为０．３μｇ／Ｌ。镉含量水平为４０μｇ／Ｌ的尿样，连续测定１１次的相对标准偏差为１．５％。尿标准参考物...?     

在线预浓集流动注射测定苯酚

基于ＶＳ－Ⅱ阴离子交换纤维对苯酚的吸附，建立了以ＶＳ－Ⅱ阴离子交换纤维柱在线预浓集、流动注射４－氨基安替比林分光光度测定苯酚的方法，方法的线性范围为０．０１－１．４０ｍｇ／Ｌ；进样频率可达９０次／ｈ，应用于环境污染水中苯酚的测定，结果满意。     

On-Line Separation and Preconcentration of Trace Metals in Biological Samples Using a Microcolumn Loaded with PAN-Modified Nanometer-Sized Titanium Dioxide,and Their Determination by ICP-AES

A flow injection analysis system incorporating a microcolumn of nanometer-sized TiO₂ loaded with 1-(2-pyridylazo)-2-naphthol (PAN) has been used for the development of an on-line multi-element method for simultaneous separation and preconcentration and subsequent determination of Cu²⁺, Co²⁺, Cr³⁺, Y³⁺, Yb³⁺ and Bi³⁺ by ICP-AES. Effects of pH, sample flow rate and volume, elution conditions, adsorption capacity and interfering ions on analyte recovery were examined. The adsorption capacity of nanometer-sized TiO₂ loaded with PAN was 4.73, 18.57, 3.81, 6.14, 4.52 and 20.35mgg^–1 for Cu²⁺, Cr³⁺, Y³⁺, Yb³⁺, Co²⁺ and Bi³⁺, respectively. The method has been applied to the analysis of trace elements in standard reference biological samples, and the results are in good agreement with the certified values.     

Determination of Non-Steroidal Anti-Inflammatory Drugs in Natural Waters Using Off-Line and On-Line SPE Followed by LC Coupled with DAD-MS

Two different procedures for simultaneous determination of six NSAIDs (diflunisal, diclofenac, fenoprofen, ibuprofen, naproxen and tolmetin) in environmental waters are described. Final analysis of target compounds is performed by reversed-phase liquid chromatography – diode array detection and mass spectrometry (HPLC-DAD and LC-MS), whereas sample preparation is based on solid-phase extraction (SPE). A variety of sorbents and their respective advantages and disadvantages are discussed. For the off-line SPE of NSAIDs from water samples, a LiChrolut RP-18 was selected out of all investigated sorbents. In case of on-line coupling of SPE with chromatographic system LiChrosphere RP-18 was selected as the best one in terms of recovery of NSAIDs evaluated, RSD and availability. The applicability of the method was also evaluated. Method detection limits were in the range of 0.7−94 ng L⁻¹. Recoveries ranged from 96 to 109% and relative standard deviations were lower than 5%. The procedures were shown to be linear over a wide range of concentration, exhibited satisfactory repeatability and accuracy, and reached limits of detection in the low ng L⁻¹ range. No breakthrough volume was observed neither for off-line SPE (in the studied range of 100, 200, 300, 500, 700, 1000 and 2000 mL of tap water sample) nor for on-line SPE (in the wide range of 10 mL, 20 mL, 30 mL, 50 mL, 70 mL, 100 mL and 200 mL of tap water sample).     

Preconcentration Systems Using Polyurethane Foam/Me-BDBD for Determination of Copper in Food Samples

A new reagent, 6-[2′-(6′-methyl-benzothiazolylazo)]-1,2-dihydroxy-3,5-benzenedisulfonic acid (Me-BDBD), was synthesised and used in on-line and off-line systems for copper preconcentration by solid-phase extraction. Spectrophotometry and Flame Atomic Absorption Spectrometry (FAAS) were the detection techniques. Polyurethane foam loaded with Me-BDBD packed in a minicolumn was used as sorbent in both systems. The spectral characteristics of Me-BDBD were investigated. The optimum pH values for maximum sorption of the metal are between 7.0 and 8.5. Copper was desorbed with 0.05 and 0.50 mol L⁻¹ hydrochloric acid solutions, for on-line and off-line systems, respectively. The effects of several foreign substances on the adsorption of copper are reported. The enrichment factors obtained were 7 (on-line) and 26 (off-line) for the systems. The proposed procedures allowed the determination of copper with detection limits of 3.4 and 1.4 μg L⁻¹ (0.85 and 0.35 μg per gram of sample) for on-line and off-line systems, respectively. The precision of the procedures was also calculated: 3.2 (on-line) and 1.9% (off-line). The validation of the procedures was carried out by analysis of certified reference material. The copper contents in corn and rice flour and black tea samples were determined by applying the proposed procedures.     

在线浓缩与流动注射分光光度法联用对水中痕量锌的测定

pH 9.3的硼砂缓冲溶液中,在吐温-80存在的条件下,锌与1-（2-吡啶偶氮）-2-萘酚在水相中能形成络合物。将浓缩技术与流动注射分析技术联用,建立了在线自动测定环境水样中痕量锌的新方法。方法的线性范围为2.0-360μg/L,检出限为0.42μg/L;对质量浓度为5.0、50μg/L的锌离子进行8次平行测定,相对标准偏差（RSD）分别为3.55%和2.14%。将该方法应用于水体中痕量锌离子的测定,结果令人满意。     

基于吸力洗脱的流动注射在线富集与火焰原子吸收联用测定水样中的镉

建立了一种基于吸力洗脱的流动注射(FI)在线富集与火焰原子吸收光谱法(FAAS)联用测定水样中痕量镉的新方法.洗脱过程依靠蠕动泵的吸力而不是推力实现洗脱剂的输送,明显降低了被分析物在洗脱过程中的分散,提高了原子吸收信号峰值(A),同时提高了富集系数(EF).进样流速6.0 mL/min;进样时间60 s,测定20 μg/L Cd2+,EF由传统方法的15提高到38;检出限为0.29 μg/L;测样频率为40个/h;相对标准偏差(RSD,n=11)为2.5%.以01‰ (V/V)的三乙醇胺(TEA)为掩蔽剂,Cd2+在水样中的回收率为93.8%～98.5%.