流动注射-抑制化学发光法测定岩白菜素

本文基于岩白菜素对鲁米诺-牛血清白蛋白体系化学发光信号显著的抑制作用,建立了快速灵敏测定岩白菜素的流动注射-化学发光分析新方法。实验发现,化学发光强度的降低值与岩白菜素质量浓度对数值呈良好的线性关系,方法的线性范围为3.0~5.0×10~5 pg/mL,检出限(3σ)为1.0pg/mL。当溶液流速为2.0mL/min时,完成一次分析过程仅需30s,采样频率120/h。本法用于片剂、人血清和尿液中岩白菜素的含量测定,回收率为98.1%~102.7%,相对标准偏差小于2.0%(n=7)。同时对化学发光反应机理进行了探讨。     

Determination of Total Chromium in Biological Samples by Automated Reagent Injection Chemiluminescence Analysis

A sensitive method for the determination of total chromium in real samples by flow injection–chemiluminescence (FI–CL) analysis was proposed. It was found that the CL intensity from luminol–lysozyme reaction could be markedly quenched, and the decrease of CL intensity was linear with the logarithm of Cr(III) concentrations over the range of 5.0 to 4000 pg mL^?1 with a detection limit of 2.0 pg mL^?1 (3σ) and relative standard deviations (RSDs) of 3.0, 2.6, and 2.0% for 10, 100, and 1000 pg mL^?1 Cr(III) (n = 7), respectively. At a flow rate of 2.0 mL min^?1, the whole process including sampling and washing could be accomplished within 36 s. The proposed CL method was successfully applied to the determination of total chromium in pharmaceutical capsules, a dietary supplement, and spiked human serum samples, with recoveries from 92.2 to 108.4% and RSDs of less than 4.0%. Using the homemade FI–CL model, the binding constant (K = 4.38 × 10⁶ L mol^?1) and the binding sites (n ≈ 1) of Cr(III) to lysozyme were given.     

A Flow Injection Chemiluminescence Method for the Determination of Protein Using Copper(II)-Alizarin Red S Complex as an Efficient Chemiluminescent Probe

A sensitive flow injection chemiluminescence (CL) method is proposed for the determination of bovine serum albumin (BSA) using Copper(II)-Alizarin Red S (ARS) complex as an efficient chemiluminescent probe. The detection is based on the binding of the copper(II)-ARS complex to proteins and the catalytic activity of copper(II)-ARS in the luminol-H₂O₂ CL system. Under the selected conditions, the CL intensity is linear with the concentration of BSA in the range of 5.0 × 10^?11 to 1.0 × 10^?9 mol · L^?1. The detection limit was 2.0 × 10^?11 mol · L^?1. The method is successfully applied to the determination of protein in urine.     

流动注射化学发光法测定制剂和血浆中的盐酸多巴胺

在碱性介质中,盐酸多巴胺对鲁米诺-KIO4化学发光体系有明显的增强作用,据此,结合流动注射技术,建立了微量快速测定盐酸多巴胺的流动注射化学发光分析法。该法线性范围为0．1—100μg∥L,检出限0．02μg／L（3σ）;对1．0μg/L盐酸多巴胺11次平行测定,其相对标准偏差为2．9％。此法已成功地用于注射剂及血浆中盐酸多巴胺的分析。     

Flow Injection Analysis of Hydrogen Peroxide,Sulfite, Formaldehyde and Hydroxymethanesulfonic Acid in Precipitation Samples

Abstract

Hydroxymethanesulfonic acid (HMSA), the reaction product of sulfite and formaldehyde plays an important part in the aqueous phase conversion of sulfite to sulfate. HMSA is fairly stable under acidic conditions and in presence of hydrogen peroxide. Sulfite is unstable under these conditions.

A flow injection set-up was developed, which allows the determination of H₂O₂, sulfite, formaldehyde and hydroxymethanesulfonic acid.

H₂O₂ analysis by amperometric detection offers the possibility of a simple, robust field instrument. The detection limit is 5μg/l and the method is linear up to 5mg/l.

Based on the 4,4-dithiodipyridine/sulfite reaction selective and sensitive spectrophotometric detections were developed for sulfite, formaldehyde and hydroxymethanesulfonic acid. The detection limit of these compounds is 50μg/l and the method is linear up to 5mg/l.

A large fraction of S(IV) is present as HMSA in fog, dew and precipitation samples in The Netherlands.     

Quantitative Monitoring of Rutin in Human Urine by Flow Injection‐Chemiluminescence Analysis

In this paper, a rapid and sensitive flow injection‐chemiluminescence (FI‐CL ) method is proposed for the quantitative determination of rutin based on the inhibitory effect of rutin on the chemiluminescence intensity from the luminol–chymotrypsin (CT ) system. The decrease of CL intensity was found to be proportional to the logarithm of rutin concentration in the range 0.1–30.0 ng/mL . A method for the quantification of rutin is proposed, with the limit of detection (LOD ) of 0.03 ng/mL (3σ). A complete analytical process including sampling and washing for rutin determination, which was conducted at a flow rate of 2.0 mL /min, could be performed completely within 30 s, yielding a sample efficiency of 120 h⁻¹. The proposed procedure was successfully applied for the determination of rutin in human urine after oral intake, with recoveries varying from 93.9 to 108.1% and relative standard derivation <4.0% (n = 5). Results showed that urine reached the maximum concentration at ~2.5 h, and the total excretion ratios were (83.5 ± 0.6) and (86.8 ± 0.7)%, respectively, for two volunteers in 8 h. The pharmacokinetic parameters, including the half‐life (1.05 ± 0.02 h), absorption rate constant (1.18 ± 0.01 h⁻¹), and elimination rate constant (0.70 ± 0.01 h⁻¹), were obtained. The possible CL mechanism of the luminol–CT –rutin reaction is discussed by FI‐CL , fluorescence, and molecular docking methods.     

Flow Injection Chemiluminescence Determination of Puerarin in Pharmaceutical Preparations Using Eosin Y‐Fenton System

A novel chemiluminescence (CL) system was established for the determination of puerarin in pharmaceutical preparations. It was shown that a strong CL signal was observed when Eosin Y reacted with the hydroxyl radicals which were generated from Fenton reagent in acidic medium. The CL intensity was decreased significantly when puerarin was added to the reaction system and partially scavenged the hydroxyl radicals in the solution. The extent of decrease in the CL intensity had a good stoichiometrical relationship with puerarin concentration. Based on this, a new method for the determination of puerarin using a flow injection chemiluminescence technique was developed. The experimental parameters that affected the CL intensity were optimized. Under the optimal conditions, the linear range for puerarin concentration was 8.0×10^?8?2.0×10^?6 mol/L (R=0.9982) with a detection limit of 7.5×10^?9 mol/L (S/N=3) and the relative standard deviation was 1.7% for 4.0×10^?7 mol/L puerarin (n=11). The proposed method was applied to the determination of puerarin in a puerarin injection with satisfactory results.     

Voltammetric Lead Determination in Aviation Fuel Samples Using a Screen‐Printed Gold Electrode and Batch‐Injection Analysis

This work presents the lead determination in aviation (bio)fuels using disposable screen‐printed gold electrodes (SPGEs) adapted on a batch‐injection cell associated with a micropipette for portable analysis. The method involves injections of 200 µL of sample or standard solutions at controlled dispensing rate (4.8 µL s^?1) during deposition step (?550 mV for 90 s), followed by anodic‐stripping voltammetry. Either samples treated by sonication or dry‐ashing can be analyzed with detection limits of 0.0071 and 0.0008 µg g^?1 Pb, respectively. A single SPGE can be applied for 60 consecutive measurements (or 120 for samples dry‐ashed). The ultrasound‐assisted treatment is faster, safer, and easily adapted for on‐site analyses, especially considering the portable characteristics of commercially‐available potentiostats and batch‐injection analysis cell using SPGEs.     

Flow Injection Analysis of Ascorbic Acid in Real Samples Using a Highly Stable Chemically Modified Screen‐Printed Electrode

A silica sol‐gel glass‐coated ferricyanide‐doped Tosflex‐modified screen‐printed electrode (designated as SG/FeCN‐Ts/SPE) was used for the mediated oxidation of ascorbic acid in neutral pH. The sol‐gel overlayer was found to stabilize the Fe(CN) ‐Tosflex system without any foul‐off and deterioration behavior through chemical interaction between the hydrophilic sites of Tosflex and oxy‐ and/or ‐hydroxy surface functional groups of silicate. The electrochemical mediation of ascorbic acid was found to follow the Michaelis‐Menten kinetic pathway. The SG/FeCN‐Ts/SPE was very stable for repetitive measurements by flow injection analysis at 0.3 V (vs. Ag/AgCl). A linear calibration plot was obtained for ascorbic acid determination up to 300 μM with sensitivity and detection limit (S/N=3) of 2.85 nA/μM and 46 nM, respectively. The system also showed tolerable interference to uric acid, urea and carbohydrates and was used for the determination of ascorbic acid in human urine, clinical tablet and apple juice.     

Direct Determination of Azathioprine in Human Fluids and Pharmaceutical Formulation Using Flow Injection Chemiluminescence Analysis

A simple, sensitive and inexpensive flow injection chemiluminescence method for the determination of azathioprine had been discovered. It was based on the fact that the weak chemiluminescent reaction of cerium(IV) with azathioprine in acidic medium, which was enhanced by the addition of rhodamine 6G. A lot of optimized experimental conditions had been studied in detail. The CL intensity was linearly related to the concentration of azathioprine in the range of 0.1–10.0 μM and the detection limit was 45.0 nM (3σ). The relative standard deviation (RSD) for the technique was 2.1% (n = 11). The method had high selectivity, sensitivity and good repeatability. The proposed method had been triumphantly applied to the determination of azathioprine in human fluids and pharmaceutical formulation with satisfactory results.     

Highly Sensitive Voltammetric Speciation and Determination of Inorganic Arsenic in Water and Alloy Samples Using Ammonium 2‐Amino‐1‐Cyclopentene‐1‐Dithiocarboxylate

A simple, fast, reproducible (2.5% RSD at 3.0 μg/L), and sensitive method is described for quantifying As(III) (0.3 μg/L detection limit, 0.5–440 μg/L dynamic range). Anodic stripping voltammetry (ASV) is performed after accumulating arsenic at a mercury film electrode at ?0.350 V vs. Ag/AgCl (saturated KCl) for 20 s in 0.2 M HCl containing 8 μM ammonium 2‐amino‐1‐cyclopentene‐1‐dithiocarboxylate (AACD), without oxygen removal. This is the first report of using AACD in ASV and in electrochemical quantification of As(III). Total arsenic is determined after sodium‐sulfite‐reduction of As(V) to As(III). Interferences are minimal. Method validation involved water and metal alloy samples.     

Trace Analysis of Methyl Tert‐butyl Ether in Water Samples Using New Ultrasound‐assisted Dispersive Liquid‐liquid Microextraction and Gas Chromatography‐flame Ionization Detection

In this study, simple and efficient ultrasound‐assisted dispersive liquid‐liquid microextraction combined with gas chromatography (GC) was developed for the preconcentration and determination of methyl‐tert‐butyl ether (MTBE) in water samples. One hundred microliters of benzyl alcohol was injected slowly into 10 mL home‐designed centrifuge glass vial containing an aqueous sample with 30% (w/v) of NaCl that was located inside the ultrasonic water bath. The formed emulsion was centrifuged and 2 μL of separated benzyl alcohol was injected into a gas chromatographic system equipped with a flame ionization detector (GC‐FID) for analysis. Several factors influencing the extraction efficiency such as the nature and volume of organic solvent, extraction temperature, ionic strength and centrifugation times were investigated and optimized. Using optimum extraction conditions a detection limit of 0.05 μg L^‐1 and a good linearity (r² = 0.998) in a calibration range of 0.1‐500 μg L^‐1 were achieved. This proposed method was successfully applied to the analysis of MTBE in tap, well and a ground water sam ple contaminated by leaking gasoline from an underground storage tank (LUST) in a gasoline service station.     

Markedly Enhanced Purge‐and‐Trap Performance and Efficiency for the Determination of Ammonium Ion in High‐Salinity Water Samples

We have previously developed a purge‐and‐trap (P&T) preconcentrator, useful for the determination of trace amounts of ammonium ion in high‐salinity water samples by ion chromatography (IC). In this study, we succeeded in improving the P&T system to markedly enhance performance and efficiency for the determination of ammonium in high‐salinity water samples. Compared to the previous work, the background signal was reduced by a factor of 9. The maximum overall collection efficiency increased greatly from 64% to 97%. With the modified P&T system, this method can be applied to a wide ammonium concentration range of 5 orders of magnitude. These were attributed to the substitution of polypropylene vessels for glass ones, the improvement of the gastight of the P&T system, the increase of the liquid depth in the purge vessel, and the use of 10 mM sulfuric acid as the trapping solution for high ammonium concentration samples. Interferences of 20 native amino acids to the ammonium determination are slightly positive, but also negligible except asparagine and glutamine. The proposed method has been successfully applied to the accurate determination of wide levels of ammonium in seawater and sweat samples.     

A Simple,Cost‐effective,and Environmentally Friendly Method for Determination of Ciprofloxacin in Drugs and Urine Samples Based on Electrogenerated Chemiluminescence

Ciprofloxacin is an antibiotic that belongs to the class of drugs known as quinolones and it is frequently used to treat a variety of bacterial infections. The present work aims the development of a simple, cost‐effective, and environmentally friendly method for the determination of ciprofloxacin in drugs and artificial urine samples due to the high importance of this antibiotic for the human health. The proposed method is based on the electrogenerated chemiluminescence (ECL) resulting from the reaction between the ciprofloxacin and the tris(2,2′‐bipyridyl)ruthenium(II) complex. This method exploits a screen‐printed carbon electrode positioned in an ECL cell with capacity to 50 μL of electrolytic solution. The ECL intensity was monitored with the aid of a photodiode. The ECL signal was simultaneously registered to the voltammetric measurements. Under optimized experimental conditions, the ECL method presented a linear response range for ciprofloxacin between 0.5 and 500 μmol L^?1 (or 0.0005 and 0.5 mmol L^?1). The proposed method presented a detection limit of 0.5 μmol L^?1 and it was successfully applied for the ciprofloxacin determination in drugs and artificial urine samples, with good accuracy and precision.     

Determination of Cadmium and Lead in Human Teeth Samples Using Dispersive Liquid‐liquid Microextraction and Graphite Furnace Atomic Absorption Spectrometry

A new method for the determination of cadmium and lead in human teeth was developed based on dispersive liquid‐liquid microextraction preconcentration and graphite furnace atomic absorption spectrometry determination. In the proposed approach, O,O‐diethyldithiophosphate (DDTP) was used as a chelating agent, and carbon tetrachloride and methanol were selected as extraction and dispersive solvents. Some factors influencing the extraction efficiency of cadmium and lead and their subsequent determination, including extraction and dispersive solvent type and volume, pH of sample solution, concentration of the chelating agent and extraction time, were studied and optimized. Under the optimum conditions, the enrichment factor of 116 and 68 for cadmium and lead were achieved. The detection limit for cadmium and lead was 5.6 and 45 ng L^?1, and the relative standard deviation (R.S.D) was 4.5% and 3.8% (n = 7, c = 1.0 ng mL^?1), respectively. Verification of the accuracy of the method was carried out by analysis of a standard reference material (NIST 1486, bone meal). The method was successfully applied to the determination of trace amount of cadmium and lead in human teeth samples with satisfactory results.     

Simultaneous Determination of Cadmium,Lead, Copper,and Thallium in Highly Saline Samples by Anodic Stripping Voltammetry (ASV) Using Mercury‐Film and Bismuth‐Film Electrodes

This paper describes a comparative study of the simultaneous determination of Cd(II), Pb(II), Tl(I), and Cu(II) in highly saline samples (seawater, hydrothermal fluids, and dialysis concentrates) by ASV using the mercury‐film electrode (MFE) and the bismuth‐film electrode (BiFE) as working electrodes. The features of MFE and BiFE as working electrodes for the single‐run ASV determinations are shown and their performances are compared with that of HMDE under similar conditions. It was observed that the stripping peak of Tl(I) was well separated from Cd(II) and Pb(II) peaks in all the studied saline samples when MFE was used. Because of the severe overlapping of Bi(III) and Cu(II) stripping peaks in the ASV using BiFE, as well as the overlapping of Pb(II) and Tl(I) stripping peaks in the ASV using HMDE, the simultaneous determination of these metals was not possible in highly saline medium using these both working electrodes. The detection limits calculated for the metals using MFE and BiFE (deposition time of 60 s) were between 0.043 and 0.070 μg L^?1 for Cd(II), between 0.060 and 0.10 μg L^?1 for Pb(II) and between 0.70 and 8.12 μg L^?1 for Tl(I) in the saline samples studied. The detection limits calculated for Cu(II) using the MFE were 0.15 and 0.50 μg L^?1 in seawater/hydrothermal fluid and dialysis concentrate samples, respectively. The methods were applied to the simultaneous determination of Cd(II), Pb(II), Tl(I), and Cu(II) in samples of seawater, hydrothermal fluids and dialysis concentrates.     

Analytical Applications of 2,6‐Diacetylpyridine‐bis‐4‐phenyl‐3‐thiosemicarbazone (2,6‐DAPBPTSC): Determination of Cd(II) in Foods and Water Samples

To the determination of trace amount of Cd(II) present in food and water samples, a selective and extractive spectrophotometric method were developed with 2,6‐diacetylpyridine‐bis‐4‐phenyl‐3‐thiosemicarbazone as a complexing agent. The yellowish orange colored metal complex, Cd(II)‐2,6‐DAPBPTSC with 1:1 (M:L) composition was extracted in to cyclohexanol at pH 9.5 and was shows maximum absorbance at λ_max 390 nm. This method obeys Beer's law in the range of 1.12‐11.25 ppm with 0.972 correlation coefficient of Cd(II)‐2,6‐DAPBPTSC complex, which is indicates linearity between the two variables. The molar absorptivity and sandell's sensitivity were found to be 6.088 × 10⁴ L mol^?1 cm^?1 and 0.0018 μg cm^?2, respectively. The instability constant calculated from Asmus' method (1.447 × 10^?4)at room temperature. The precision and accuracy of the method were checked by relative standard deviation (n = 5), 0.929 and its detection limit, 0.0060 μg mL^?1. The interfering effects of various cations and anions were also studied. The proposed method was successfully applied to the determination of Cd(II) in foods and water samples, and was evaluated its performance in terms of Student ‘t’ test and Variance ‘f’ test, which indicates the significance of present method. The inter comparison of the experimental values, using atomic absorption spectrometer (AAS), was also repoted.     

Flow Injection Analysis of Aluminum Chlorohydrate in Antiperspirant Deodorants Using a Built‐in Three‐in‐one Screen‐Printed Silver Electrode

A screen‐printed silver strip with a built‐in three‐in‐one electrode (SPAgE) configuration of Ag‐working, Ag‐counter and Ag/Ag_xO (silver oxides) pseudoreference electrodes has been developed for sensitive and selective electrochemical flow injection analysis (FIA) of aluminum chlorohydrate (ACH) present in antiperspirants, through the free Cl^? ion liberated from ACH in aqueous medium, as a redox signal at Ag‐working electrode in pH 6 phosphate buffer solution (PBS). The solution phase and instrumental parameters were systematically optimized. The calibration graph was linear in the window 1–200 ppm concentration of ACH and the lowest detection limit (S/N=3) was 295 ppb with a slope of 0.0989 μA/ppm and regression coefficient of 0.998. Calculated relative standard deviation (RSD) values for the detection of 5 and 50 ppm ACH by this method are 2.21 % and 2.16 %, respectively. Four different antiperspirant deodorants real samples with and without ACH content were successfully analyzed and the detected values obtained were found to be in good agreement with the product labeled values.     

Synthesis of New Reagent 2,6‐Diacetylpyridine Bis‐4‐Phenyl‐3‐Thiosemicarbazone (2,6‐DAPBPTSC): Selective,Sensitive and Extractive Spectrophotometric Determination of Co(II) in Vegetable,Soil, Pharmaceutical and Alloy Samples

New synthesized reagent 2,6‐diacetylpyridine bis‐4‐phenyl‐3‐thiosemicarbazone (2,6‐DAPBPTSC) is proposed as a sensitive and selective analytical reagent for the extractive spectrophotometric determination of cobalt(II). Cobalt(II) forms a reddish brown colored complex with 2,6‐DAPBPTSC, which is extracted into isoamylalcohol, under optimum conditions. The maximum absorption of the isoamylalcohol extract is measured at 400 nm. Beer's law is applied in the range 0.6‐6.0 ppm of cobalt(II). The molar absorptivity and Sandell's sensitivity of the complex is calculated as 2.2 × 10⁴ L mol^?1 cm^?1 and 2.68 × 10^?3 μg cm^?2, respectively. An adequate linearity with a correlation coefficient value of 0.969 is obtained for the Co(II)‐2,6‐DAPBPTSC complex. The instability constant of the complex, calculated from Asmus' method is 3.75 × 10^?4 The precision and accuracy of the method is checked with calculation of relative standard deviation (n = 5), 0.388 and the detection limit a value is 0.0028 μg mL^?1. The method is successfully employed for the determination of cobalt(II) in real samples, such as vegetables, soil, water samples, standard alloy samples, and the performance of the present method was evaluated in terms of Student ‘t’ test and Variance ‘f’ test, which indicates the significance of the present method is an inter comparison of the experimental values, using atomic absorption spectrometer (AAS).     

Analysis of trace‐level nitrated polycyclic aromatic hydrocarbons in water samples by solid‐phase microextraction with gas chromatography and mass spectrometry

A solid‐phase microextraction coupled with gas chromatography and mass spectrometry method has been developed for the determination of ten nitrated polycyclic aromatic hydrocarbons in water samples. Five different kinds of commerical fibers were used to compare the extraction efficiency, including 65 μm polydimethylsiloxane/divinylbenzene, 100 μm polydimethylsiloxane, 30 μm polydimethylsiloxane, 7 μm polydimethylsiloxane, and 85 μm polyacrylate fibers. Five factors were also selected to optimize conditions, including extraction temperature, time, stirring speed, salt concentration, and headspace volume. Taguchi design was applied to design the experiments and obtain the best parameters. The results show that 65 μm polydimethylsiloxane/divinylbenzene fiber directly immersed into aqueous solution for 35 min at 55°C with a constant stirring rate of 1150 rpm were the optimal conditions. Under these conditions, the limits of quantification were 0.007–0.063 μg/L, and the relative standard deviation based on six replicates ranged from 2.8 to 9.5%. The spiked recoveries ranged from 69.1 to 110.1%. Intra‐ and inter day relative standard deviations at three concentration levels were less than 12%, and the recoveries were 66.4–111.5%. The proposed method is reliable for analyzing nitrated polycyclic aromatic hydrocarbons in different water samples.