Automated Determination of Captopril by Flow and Sequential Injection Analysis: A Review

The present study intends to present a review of automated methods for the determination of Captopril—an angiotensin converting enzyme (ACE) inhibitor—using flow or sequential injection analysis. The review covers a range of more than fifteen years of published research on this topic (1993–today). The methods are classified according to the detection systems in three categories, namely spectrophotometric, chemiluminescence, and electroanalytical. The principles and main analytical figures of merit of the reported studies are presented and discussed.     

顺序注射催化动力学光度法测定废水中的痕量酚

在硫酸介质中,利用酚催化溴酸钠氧化桔花青的反应,联用顺序注射技术建立了顺序注射催化动力学光度法测定废水中痕量酚的新方法。方法的线性范围0．4—3．5mg／L,检出限0．1mg／L。该法测定快速简便,常见共存物干扰小,消耗试剂量小,减少了二次污染,用于工业废水中的痕量酚的测定,并与4-氨基安替比林比色法对照,结果无显著差异。     

Flow Injection Spectrophotometric Determination of Dipyrone in Pharmaceutical Formulations Using Fe(III) as Reagent

A flow injection spectrophotometric procedure with symmetric merging zones for dipyrone determination in pharmaceutical formulations is proposed. The determination is based on the formation of a blue complex (monitored at a wavelength of 642 nm) yield in the complexation reaction of dipyrone with Fe(III) in acid medium. Under optimum conditions, a calibration curve was obtained from 3.5 to 281 mg L^?1 with a detection limit of 2.8 mg L^?1 and the samples throughput was 80 h^?1. The analytical results obtained for commercial formulation samples by applying the proposed method were in good agreement with labeled values and those obtained by a comparative procedure at a 95% confidence level.     

A Stopped Flow Injection – Chemical Relaxation – Catalytic Spectrophotometric Procedure for the Determination of Cobalt

 A concentration-jump chemical relaxation catalytic procedure by using stopped flow injection is described with detection by spectrophotometry. The photoreduction of the Fe(III)-bipyridyl complex to Fe(II)-bipyridyl is pre-equilibrated at dark for at least 12 h. This solution is afterwards delivered by a peristaltic pump and mixed up with a stream of Co²⁺ solution as a catalyst. The mixture is confluenced down-stream with a flow of Fe(III) solution from a second pump, the concentration of which is about 30% of the pre-equilibrated Fe(III)-bipyridyl solution and acts as the perturbation (concentration-jump). The chemical relaxation process was monitored under thermodynamically non-equilibrium state, and the characteristic parameter of the relaxation process, relaxation time τ, is derived. The calibration graph between 1/τ and cobalt concentration is linear within 0.1–2.5 μg mL⁻¹. The detection limit (LOD) and precision (RSD) are 9 ng mL⁻¹ and 1.6%, respectively, both have been improved as compared to 12 ng mL⁻¹ and 3.6% with a former reported manually operated procedure. The present procedure has been applied to the determination of cobalt in a certified reference material and a soil sample. Received June 15, 2002; accepted October 28, 2002     

Spectrophotometric Determination of Furosemide Based on Its Complexation with Fe(III) in Ethanolic Medium Using a Flow Injection Procedure

Abstract

A fast flow injection procedure with spectrophotometric detection based on the furosemide complexation with Fe(III) ions in ethanolic media is described. As carrier the flow single line system configuration used an ethanolic 10^?2 mol L^?1 Fe(III) solution flowing at 1.0 mL min^?1, a 50 cm sample loop (250 µL total sample injection), and a 50 cm long reactor coil, at room temperature. The detection at 513 nm presented a linear dynamic range from 1.00×10^?4 to 1.00×10^?2 mol L^?1, obeying the linear equation Abs=8.9×10^?3+22.3×[furosemide] (r=0.998, n=7). The limit of detection (3σ/slope) was 3.00×10^?5 mol L^?1. The proposed method was applied to four commercial samples from different suppliers, as tablets and ampoules, and a synthetic urine sample spiked with the analyte without an effect from the other substances present in the formulation. The proposed procedure presented an analytical frequency of 95 measurements per hour. The results agreed with those from both the label and those determined by a spectrophotometric comparative procedure. Recoveries close to 100% were found in the commercial formulations and synthetic urine matrixes.     

流动注射催化分光光度法测定钌的研究

利用钌（Ⅲ）对过氧化氢氧化还原型百里酚酞显色反应的显著催化作用，建立了钌的新流动注射催化分光光度分析法，该法快速灵敏、简便，用于实际样品分析，结果良好。     

甲氧氯普胺的流动注射光度分析

基于在盐酸介质中,利用甲氧氯普胺－亚硝酸钠－α－萘胺的重氮化－偶合反应,建立了流动注射光度法测定甲氯普胺的新方法,利用单纯形优化法选择了最佳实验条件。方法的线性范围为0.0-30mg/L,进样频率为160／h。11次重复测定的相对标准偏差小于0.6％,该方法已成功用于药物中甲氧氯普胺含量的测定,测定结果与药典法对照,并经统计学处理,结果满意。     

芯片式流通池顺序注射化学发光法测定水中的亚硝酸根

微流控芯片(Microfluidic chips)是微全分析系统(μTAS)研究中最为活跃的领域,在仪器微型化方面展现出很多的优点^[1].化学发光由于其自身的特性在微芯片检测中应用逐渐增多^[2,3].     

Flow Injection Analysis Spectrophotometric Determination of Platinum

Abstract

A new, simple, rapid, and selective procedure for the flow injection analysis (FIA) spectrophotometric determination of platement (Pt) is described. The method is based on the color reaction of Pt(IV) with SnCl₂ in the HCl medium. The mixed surfactants, i.e., cetylpyridinium chloride (CPC)+triton X‐100 (TX‐100) are used to enhance sensitivity of the method. The value of apparent molar absorptivity in the term of Pt is (3.00)×10³ L mol^?1 cm^?1 at absorption maximum, 405 nm. The detection limit (causing absorbance greater than 3×std. dev.) of the method is 150 ng/mL^?1. The optimum concentration range for the determination of Pt is 0.5–18 µg/mL^?1 with slope, intercept and correlation coefficient 0.0086, ?0.001, and +0.99, respectively. The sample throughput of the method is 120 samples/h^?1 at the flow rate of 3.7 mL/min^?1. The composition of the complex, and the reaction mechanism involved are discussed. The effect of FIA and analytical variables on the determination of the metal is optimized. The method has been tested for the analysis of Pt to the catalytic materials.     

芯片式流通池顺序注射可更新表面反射光谱法用于酶反应检测

将芯片式流通池顺序注射可更新表面反射光谱法用于酶反应检测。HRP催化H2O2氧化BPR底物的反应用于对H2O2的检测。此反应体系与葡萄糖氧化酶联用，用于对血清中葡萄糖的检测。     

Indirect Spectrophotometric Determination of Vanadium(IV) by Flow Injection Analysis Based on the Redox Reaction with Copper(II) in the Presence of Neocuproine

Abstract

An indirect photometric method with a continuous-flow analysis is presented for the determination of trace amounts of vanadium(IV). It is based on the redox reaction of copper(II) with vanadium(1V) in the presence of neocuproine. In the presence of neocuproine, copper(I1) is reduced easily by vanadium(I V) to a copper(1)-neocuproine complex, which shows a n absorption maximum at 454 nm. By measuring t h e absorbance of the complex at this wavelength, vanadium(1V) in t h e range 2×10^?6 - 8 × mol dm^?5 mol dm^?3 can be determined at a rate of 120 samples h^?1. The fractional determination of vanadium(1V) and iron(I1) is also studied.     

Flow-Batch Method with a Sequential Injection System for Spectrophotometric Determination of Selenium(IV) in Selenium-Enriched Yeast Using o-Phenylenediamine

A precise, accurate, and reliable flow-batch spectrophotometric method for the determination of selenium (IV) was developed using o-phenylenediamine as a reagent with a sequential injection monosegmented flow system incorporating a simple heating unit. The reaction zones of selenium(IV) and o-phenylenediamine were mixed and heated in a chamber at 62°C for 5 minutes. The piaselanol complexes were then detected at a maximum absorption wavelength of 335 nm. In-line single standard calibration and standard addition procedures were developed employing the monosegmented flow technique. Under the optimized conditions, a linear calibration graph in a range of 0.1–4.0 mg L^?1 selenium (IV) was obtained with limits of detection and quantitation of 0.01 and 0.1 mg L^?1, respectively. Relative standard deviations were 2% [for both 0.1 and 0.5 mg L^?1 selenium (IV) (n = 11)]. A sample throughput of 2 h^?1 using four standard addition levels was achieved. The developed system was successfully applied to raw selenium-enriched yeast samples. The analyses performed by the developed method agreed well with those obtained from a standard inductively coupled plasma mass spectrometry method.     

Development of a Sequential Injection Analysis Device for the Determination of Total Polyphenol Index in Wine

A sequential injection analysis method is developed for the determination of the total polyphenol index in wines. The determination is based on the Folin-Ciocalteu reaction, which is monitored spectrophotometrically. Interactions between experimental variables and their optimal levels were investigated using factorial designs. The proposed system is fully computerised and is able to monitor polyphenol index in real samples of white, sweet and red wines. The calibration graph is linear from 5 to 200mg·L^–1 using Tannic acid as standard, with a detection limit of 3.2mg·L^–1. Interferences are studied. For validation purposes the proposed methodology was applied to the determination of the total polyphenol index in different types of wines and compared with earlier alternatives in order to assess their performance.     

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。     

流动注射分光光度法测定皮革制品中的甲醛

研究了流动注射变色酸分光光度法测定皮革制品中的甲醛。与传统的变色酸光度法相比,该方法具有灵敏度更高,干扰更少的特点。在0.4 mol/L硫酸介质中,甲醛与变色酸在85℃左右形成络合物,该络合物在390 nm有最大吸收峰,且能稳定存在至少96 h。详细考察了各种测试条件如萃取剂、萃取时间、显色时间、反应温度、反应时间等对甲醛测定结果的影响,优化了反应的化学因素和流动注射系统反应条件。该方法的检出限和线性范围分别为0.1μg/L(3σ)和50~1000μg/L,相对标准偏差为0.56%(连续注射500μg/L甲醛标液11次)。该方法成功用于皮革制品或者皮质材料中的甲醛的测定。     

Simultaneous Spectrophotometric Determination of Silicate and Phosphate by Flow Injection Analysis

Abstract

A method is reported for the simultaneous determination of phosphate and silicate by flow injection analysis based on the different rate of formation of the heteromolybdic acids of the two anions. Measurements are based on the colour of the ion-pairs formed between the said molybdic acids and Rhodamine B. The method allows the determination of the two anions at a rate of 20 samples/h over the ranges 0.05–2.5 ppm (phosphate) and 0.8–15 ppm (silicate), which allows application to a variety of waters.     

Kinetic Flow Injection Spectrophotometric Determination of Nitrite by its Catalytic Effect on the Oxidation of Chlorophosphonazo-pN by Bromate

Abstract

A flow injection kinetic method has been developed for the determination of nitrite, based on its catalytic effect on bromate oxidation of chlorophosphonazo-pN in H₂SO₄ medium. The reaction is followed spectrophotometrically by measuring the decrease in the absorbance at 551 nm. The sampling frequency was 83 h^?1. The calibration curve was linear between 0.050 and 1.00 μg/ml, and the detection limit was 0.018 μg/ml. The proposed method was applied to the determination of nitrite in waters and soil with satisfactory results.     

用2—羟基—3—羧基—5—磺酸基苯重氮氨基偶氮苯流动注射分光光度法测定汞

研究了在乳化剂ＯＰ存在下，２－羟基－３－羧基－５－磺酸基苯重氮氨基偶氮苯（ＨＣＳＤＡＡ）－汞（Ⅱ）显色体系流动注射分光光度法。用ＰＨ１０．０－１０．５的Ｎａ２Ｂ４Ｏ７－ＮａＯＨ缓冲溶液作载流，汞（Ⅱ）与ＨＣＳＤＡＡ和乳化剂ＯＰ的混合试剂反应形成红色络合物。用于测定汞时，方法的线性范围是０．０５－１．０ｍｇ／Ｌ，检测限为０．０１６ｍｇ／Ｌ，进样频率为１００样／ｈ。直接应用于头发、自来水和废水中微量汞