Sensitive determination of Fenamiphos in water samples by flow injection photoinduced chemiluminescence

In this work, a sensitive flow injection chemiluminescence (FI-CL) method for the determination of nematicide Fenamiphos in a rapid and simple way is proposed. Fenamiphos is first photodegraded in basic medium. These photofragments react with Ce(IV) providing the chemiluminescence signal. To the authors’ knowledge, no chemiluminescence method has been described in the literature for the determination of the nematicide Fenamiphos. All physical and chemical parameters in the flow injection chemiluminescence system were optimized in order to obtain the best sensitivity, selectivity and sample throughput. Before the injection of the sample in the FI-CL system, a preconcentration step with solid phase extraction C18 cartridges was performed. By applying solid phase extraction (SPE) to 250?mL of standard (final volume 10?mL), the linear dynamic range was between 3.4 and 60?µg?L^?1, and the detection limit was 1?µg?L^?1. When SPE was applied to 500?mL of standard (final volume 10?mL), the detection limit was 0.5?µg?L^?1. These detection limits are below the emission limit value established by the Spanish Regulations of the Hydraulic Public Domain for pesticides (50?µg?L^?1) and of the same order as the limit established for total pesticides (0.5?µg?L^?1) at European Directive on the quality of water for human consumption. The sample throughput was 126 hour^?1. Intraday and interday coefficients of variation were below 10% in all cases. No interference was registered in presence of usual concentrations of anions, cations and other organophosphorus pesticides. The method was successfully applied to the analysis of environmental water samples, obtaining recoveries between 96 and 107.5%.     

Determination of arsenic(V) in freshwaters by flow injection with luminol chemiluminescence detection

A simple and rapid flow injection (FI) method is reported for the determination of arsenic(V) based on luminol chemiluminescence (CL) detection. The molybdoarsenic heteropoly acid formed by arsenic and ammonium molybdate in the presence of ammonium vanadate in acidic conditions generated chemiluminescence emission via the oxidation of luminol. The limit of detection was 0.15 μg L^?1, with a sample throughput 120 h^?1. A linear calibration graph was obtained over the range 0.15 to 7.5 μg L^?1 (r ² = 0.9989; n = 9) with relative standard deviation (n = 4) in the range 0.8 to 2.5%. Interfering cations were removed by passing the sample through an in-line iminodiacetate chelating column and phosphate (at 0.6 mg L^?1) was removed off-line by magnesium-induced coprecipitation (MAGIC) method. The method was applied to freshwater samples and the results obtained were in reasonable agreement with the results obtained using HGAAS as the reference method.     

Determination of trace amounts of chromium (VI) by flow injection analysis with chemiluminescence detection

A new sensitive chemiluminescence (CL) method combined with continuous flow injection analysis is described for the determination of Cr(VI). Strong CL signals were generated by Cr(VI)-catalysed oxidation of gallic acid in the presence of potassium permanganate and hydrogen peroxide. Effects of reagent concentrations, temperature, pH, flow rates, mixing coil length and mixing flow sequences on the chemiluminescence intensity were studied. Under the optimised experimental conditions, the relationship between the logarithm of concentration (log?C) of Cr(VI) and the logarithm of intensity (log?I) is linear over the range of 2?×?10^?11 – 5?×?10^?4?mol?L^?1, with the detection limit (3σ) of 4?×?10^?12?mol?L^?1. Relative standard deviation of ten measurements of 1?×?10^?9?mol?L^?1 Cr(VI) is 1.7%. This flow injection analysis (FIA) system proved to be able to analyse up to 40 samples h^?1. Effects of various interferences possibly present in the water samples were investigated. Most cations and anions, as well as organic compounds, did not interfere with the determination of Cr(VI) in water samples. The experimental results obtained for chromium in reference materials were also in good agreement with the certified values.     

流动注射化学发光法测定人体血清中的胆固醇

流行病学和临床证明,血清中胆固醇含量的高低和人体的心血管疾病等有着十分密切的关系[1],因而血清胆固醇测定可作为肝脏功能、胆汁功能、肠吸收、冠状动脉疾病、甲状腺功能和肾上腺疾病的诊断指征。血清中胆固醇含量的测定方法有分光光度法、酶法、化学发光法、色谱法、气质联     

流动注射化学发光法测定茶饮料中的茶多酚

在碱性条件下,茶多酚对鲁米诺-KMnO4化学发光体系具有较强的抑制作用,据此建立了茶多酚的流动注射化学发光测定法。该法的化学发光抑制值ΔICL与茶多酚质量浓度在2.0×10-6~5.0×10-4mg/mL范围内,呈现出良好的线性关系,检出限为1.2×10-7mg/mL,对1.0×10-5mg/mL茶多酚测定的相对标准偏差为2.9%(n=11)。用于茶饮料中茶多酚的测定。     

精氨酸的流动注射化学发光法测定

在碱性介质中,精氨酸对硫氰化钾 鲁米诺化学发光体系有增敏作用,建立了用硫氰化钾 鲁米诺 精氨酸体系测定精氨酸的新方法。用该方法测定精氨酸的线性范围为0.01～2.0μg/mL,检出限0.01μg/mL,采样频率为190次/h,对3μg/mL的精氨酸连续平行测量10次,RSD为1.2%。用该方法对皮革屑中酶法提取的精氨酸进行了测定,并与氨基酸测定仪测定的结果进行了比较。     

ClO--鲁米诺流动注射-抑制化学发光法测定银杏黄酮

基于在碱性条件下,银杏黄酮对ClO--鲁米诺体系有显著的抑制作用,结合反相流动注射技术,建立了流动注射-抑制化学发光测定银杏提取物中的银杏黄酮.银杏黄酮质量浓度在0.4～14.0 μg/mL范围与相对发光强度呈线性关系,检出限为0.06 μg/mL,采样频率为120次/h,对10.0 μg/mL的银杏黄酮平行测定11次,其RSD为1.2%,回收率为98.0%～104%.该方法可用于银杏黄酮制剂的测定.     

流动注射电化学发光分析法测定甲磺酸培氟沙星

甲磺酸培氟沙星为第三代喹诺酮类抗菌药,疗效好,抗菌谱更广,且对青霉素、头孢菌素、氨基苷类耐药菌株均有效,在临床上被广泛使用。本文发现,在Na2CO3-NaHCO3碱性溶液中,1．40V电解电位下,鲁米诺在铂电极上的弱电化学发光信号可以被甲磺酸培氟沙星强烈地增敏,据此建立了甲磺酸培氟沙星的流动注射电化学发光分析方法。     

流动注射化学发光法测定有机磷农药残留量

基于K2S2O8在紫外光催化下可将有机磷消解为正磷酸盐,而正磷酸盐在酸性条件下可与钼酸盐、钒酸盐形成具有氧化性的磷钼钒杂多酸,其可直接氧化碱性鲁米诺产生强的化学发光,本文结合流动注射技术,提出了一种测定有机磷农药残留量的化学发光新方法。其线性范围为1.0×10-9~1.0×10-5g/mL,检出限为8.0×10-10g/mL。对2.0×10-7g/mL的磷进行11次平行测定,其RSD为4.8%。并分别测定了3种有机磷农药。     

流动注射-化学发光法测定富马酸依美斯汀

在酸性条件下,KMnO4与甲醛能够产生微弱的化学发光,而富马酸依美斯汀的存在能够大大增强该化学发光强度;结合流动注射技术,建立了测定富马酸依美斯汀的流动注射-化学发光新方法。该方法的线性范围分别为3.0×10-8～2.0×10-7g/mL,2.0×10-7～1.0×10-6g/mL和1.0×10-6～8.0×10-6g/mL。检出限为1.0×10-8g/mL,对2.0×10-6g/mL富马酸依美斯汀滴眼液平行测定11次,其相对标准偏差为1.3%。该方法已成功应用于滴眼液中富马酸依美斯汀的含量测定。     

Determination of iodide by detection of iodine using gas-diffusion flow injection and chemiluminescence

This work describes development of a flow injection (FI) system for determination of iodide, based on the chemiluminescence (CL) reaction between iodine and luminol. Iodide in the sample zone is oxidized to iodine. Employment of a gas-diffusion (GD) unit allows for selective detection of the generated CL (425 nm). Preliminary results showed for concentrations of less than 2 mg L⁻¹, that signals were irreproducible and that the calibration was not linear.In order to solve these problems, a method of ‘membrane conditioning’ was investigated, in which iodide stream was continuously merged with oxidant to generate I₂ that conditioned the GD membrane and tubing. This minimized surface interaction between the active surface and the I₂ generated from the samples, thus improving both precision and sensitivity. By employing membrane conditioning, it has been possible to reliably detect concentrations down to 0.1 mg L⁻¹.At the optimized condition, an excellent linear calibration (r² = 0.999) was obtained from 0.1 to 1.0 mg L⁻¹. The method was successfully applied to determine iodide in some pharmaceutical products such as potassium iodide tablets and a liquid patent medicine. However, for vitamin tablets, ascorbic acid was found to interfere seriously by causing a negative signal.     

Determination of nanomolar concentrations of phosphate in freshwaters using flow injection with luminol chemiluminescence detection

A simple and rapid flow injection (FI) method is reported for the determination of phosphate (as molybdate reactive P) in freshwaters based on luminol chemiluminescence (CL) detection. The molybdophosphoric heteropoly acid formed by phosphate and ammonium molybdate in acidic conditions generated chemiluminescence emission via the oxidation of luminol. The detection limit (3× standard deviation of blank) was 0.03 μg P l⁻¹ (1.0 nM), with a sample throughput of 180 h⁻¹. The calibration graph was linear over the range 0.032–3.26 μg P l⁻¹ (r²=0.9880) with relative standard deviations (n=4) in the range 1.2–4.7%. Interfering cations (Ca(II), Mg(II), Ni(II), Zn(II), Cu(II), Co(II), Fe(II) and Fe(III)) were removed by passing the sample through an in-line iminodiacetate chelating column. Silicate interference (at 5 mg Si l⁻¹) was effectively masked by the addition of tartaric acid and other common anions (Cl⁻, SO₄²⁻, HCO₃⁻, NO₃⁻ and NO₂⁻) did not interfere at their maximum admissible concentrations in freshwaters. The method was applied to freshwater samples and the results (26.1±1.1–62.0±0.4 μg P l⁻¹) were not significantly different (P=0.05) from results obtained using a segmented flow analyser method with spectrophotometric detection (24.4±4.45–84.0±16.0 μg P l⁻¹).     

H2O2-Luminol流动注射-抑制化学发光法测定银杏黄酮

基于在碱性条件下,银杏黄酮对H2O2 Luminol体系有显著的抑制作用,结合反相流动注射技术,首次建立了流动注射 抑制化学发光测定银杏提取物中的银杏黄酮。银杏黄酮质量浓度在0.2～20.0μg mL范围与相对发光强度呈线性关系,检出限为0.1μg mL,采样频率为140次 h,对10.0μg mL的银杏黄酮平行测定11次,其RSD为1.5%,回收率为100.0%～100.2%。该方法可用于银杏黄酮制剂的测定。     

反相流动注射胶束增敏化学发光分析法测定硝苯地平

基于胶束介质中硝苯地平对碱性鲁米诺-过氧化氢化学发光体系的增敏作用,结合反相流动注射技术,建立了流动注射化学发光分析法测定硝苯地平的新方法.硝苯地平浓度在3.5×10-10～4.0×10-8 g·mL-1范围内时,化学发光强度与硝苯地平的浓度呈良好的线性关系,其相对标准偏差为1.4%(n=11,c=3.5×10-9 g...     

反向流动注射化学发光法测定姜黄素

铁氰化钾氧化鲁米诺在碱性介质中产生化学发光,姜黄素对该体系化学发光具有强烈的抑制作用。因此,利用该化学发光的抑制体系,结合反向流动注射技术,建立了测定大黄类药物姜黄素含量的新方法。在优化的条件下,化学发光抑制信号强度ΔI与姜黄素的浓度分别在1×10-7~1×10-6和1×10-6~1×10-5mol/L范围内呈良好的线性关系,检出限为1×10-9mol/L。对2.0×10-6mol/L的姜黄素进行平行测定10次,得相对标准偏差(RSD)为1.8%。方法应用于中药姜黄中姜黄素(总姜黄素计)的含量测定。     

流动注射-抑制化学发光法测定法莫替T、西咪替T和雷尼替丁

在弱碱性的多聚磷酸钠介质中,二价铜离子、过氧化氢和染料罗丹明B混合可以产生较强的化学发光,法莫替丁、西咪替丁和雷尼替丁对此发光有较强的抑制作用,其抑制发光强度与法莫替丁、西咪替丁和雷尼替丁的质量浓度在0.005～1.0 mg/L范围内呈线性关系,基于此,结合流动注射技术,建立了一种直接测定法莫替丁、西咪替丁和雷尼替丁的化学发光新方法.该方法对法莫替丁、西咪替丁和雷尼替丁的检出限分别为2.7、2.2、2.0μg/L.对500μg/L法莫替丁、西咪替丁和雷尼替丁平行测定11次,其相对标准偏差分别为2.1%,2.4%,2.5%.该方法已成功用于药品中法莫替丁、西咪替丁和雷尼替丁含量的测定.     

反相流动注射化学发光法测定黄芩苷

在碱性介质中,K3Fe(CN)6氧化鲁米诺产生化学发光,黄芩苷对该体系化学发光具有强烈的抑制作用。利用该化学发光的抑制体系,结合反相流动注射技术,建立了测定黄酮类药物黄芩苷含量的新方法。在优化的条件下,黄芩苷浓度在1.0×10-8～1.0×10-7和3.0×10-7～4.0×10-6mol/L范围内与化学发光抑制强度ΔI呈良好的线性关系,检出限为1.0×10-9mol/L,对3.0×10-7mol/L的黄芩苷进行平行测定10次,得相对标准偏差(RSD)为1.7%。该方法可应用于银黄口服液中黄芩提取物(黄芩苷计)的含量测定。     

流动注射化学发光法测定青霉素G钾

在甲醛的存在下,酸性KMnO4与青霉素G钾能够产生很强的化学发光,从而建立了KMnO4-甲醛-青霉素G钾化学发光体系来测定青霉素G钾.青霉素G钾的测定线性范围为2.0×10-7～1.0×10-5 g/mL,方法的检出限为1.4×10-7 g/mL,对4.0×10-7 g/mL的青霉素G钾进行11次平行测定,相对标准偏差为1.0%,用此法测定青霉素G钾取得了较好的结果.     

Determination of trivalent europium using flow injection chemiluminescence method

A simple flow injection chemiluminescence (CL) analysis method for the determination of europium in mineral samples is reported. It is based on luminescence produced by NaIO₄-H₂O₂ CL system sensitized by [Eu(EDTA)]⁻. The relative chemiluminescence intensity of the Eu³⁺-EDTA-NaIO₄-H₂O₂ system is proportional to the amount of Eu³⁺. The optimized experimental conditions were investigated. The linear range and detection limit for Eu³⁺ are 2.0×10⁻⁷ to 1.0×10⁻⁵ and 6.2×10⁻⁸ M, respectively. The sample throughput of the method is 80 samples/h. This method was successfully applied to the determination of europium in rare earth oxides. And the mechanism of chemiluminescence is proposed.     

Selective determination of amino acids using flow injection analysis coupled with chemiluminescence detection

The determination of the amino acids proline, histidine, tyrosine, arginine, phenylalanine and tryptophan using flow injection analysis (FIA) with chemiluminescence detection is described. Proline was the only amino acid to exhibit chemiluminescence with the tris(2,2-bipyridyl)ruthenium(III) reaction at pH 10. While, histidine was found to selectively enhance the reaction of luminol with Mn(II) salts in a basic medium. Acidic potassium permanganate chemiluminescence was able to selectively determine tyrosine at pH 6.75. Low pressure separations using a C18 guard column allowed the simultaneous determination of tyrosine and tryptophan or phenylalanine and tryptophan with acidic potassium permanganate and copper(II)-amino acid-hydrogen peroxide chemiluminescence, respectively. Precision for each method was less than 3.9% (R.S.D.) for five replicates of a standard (1×10⁻⁵ M) and the detection limits ranged between 4×10⁻⁹ and 7×10⁻⁶ M. Preliminary investigations revealed that the methodology developed was able to selectively determine the individual amino acids in an equimolar mixture of the 20 naturally occurring amino acids.