Determination of Gallic Acid by Flow Injection Analysis Based on Luminol‐AgNO3‐Ag NPs Chemiluminescence System

A novel flow injection procedure has been developed for the determination of gallic acid based on the enhancement function for luminol‐AgNO₃‐Ag NPs chemiluminescence (CL) system by gallic acid. The enhancement mechanism was proposed for the reinforcing effect of the gallic acid on the CL system. The UV‐vis absorption spectrum and CL emission spectrum were applied to confirm the mechanism. The method is simple, rapid and sensitive with a detection limit of 5×10^?10 g·mL^?1 and a linear range of 8.0×10^?10–1.0×10^?7 g·mL^?1. The relative standard deviation (RSD) is 1.3% for eleven measurements of 5×10^?8 g·mL^?1 gallic acid. The method has been successfully applied to the determination of gallic acid in Chinese proprietary medicine–Jianmin Yanhou tablets and synthesized samples.     

A New Flow‐Injection Chemiluminescence Method for the Determination of Acyclovir and Gancyclovir

Abstract

A rapid and sensitive flow‐injection chemiluminescence (FI‐CL) method, which is based on the CL intensity that generated from the redox reaction of Ce(IV)‐rhodamine B in H₂SO₄ medium, for the determination of acyclovir and gancyclovir is described. For acyclovir, the determination range is 3×10^?8 g mL^?1–7×10^?5 g mL^?1, with 1.56×10^?8 g mL^?1 as its determination limit. During 11 repeated measurements for 1×10^?6 g mL^?1 acyclovir, the relative standard deviation was 2.08%. For gancyclovir, the determination range was 5×10^?8 g mL^?1–7×10^?5 g mL^?1, with 2.35×10^?8 g mL^?1 as its determination limit. The relative standard deviation is 2.83% with 11 repeated measurements of 1×10^?6 g mL^?1 gancyclovir. This method can be successfully used to determine the content of acyclovir and gancyclovir in injections, acyclovir in eye drops, and, maybe, also for other ciclovirs.     

Molecular Imprinting-Chemiluminescence Sensor for the Determination of Amoxicillin

The amoxicillin-imprinted polymer was synthesized with methacrylic acid (MAA) as a functional monomer and ethylene glycol dimethacrylate (EGDMA) as a cross-linker. The binding characteristic of the imprinted polymer to amoxicillin was evaluated by equilibrium binding experiments. Using the imprinted polymer as recognition material, 3-(3′-nitrophenyl)-5(2′-sulfonylphenylazo)-rhodanine (4NRASP) was synthesized by the authors and was used as chemiluminescence (CL) reagent. A novel chemiluminescence (CL) sensor for the determination of amoxicillin was developed based on the CL reaction of amoxicillin with potassium permanganate in an acidic medium. The sensor displayed excellent selectivity and high sensitivity. The linear response range of the sensor was from 5.0 × 10^?9 to 1.0 × 10^?6 g · mL^?1 (r = 0.9985) and the detection limit was 1.3 × 10^?9 g · mL^?1. The relative standard deviation for the determination of 1.0 × 10^?7 g · mL^?1 amoxicillin solution was 1.7% (n = 11). The sensor was applied to the determination of amoxicillin in urine samples with satisfactory results.     

Flow Injection Chemiluminescence Sensor with Novel Rhodanine Ramification for Determination of Fenfluramine Based on Molecularly Imprinted Polymer

Abstract

Flow injection chemiluminescence (FI-CL) with molecularly imprinted polymer (MIP) was applied to determine fenfluramine. The fenfluramine-imprinted polymer was prepared with acrylamide (AM) as functional monomer and ethylene glycol dimethacrylate (EGDMA) as cross-linker. Methyl and sulfonic group were introduced to rhodanine matrix, and a novel rhodanine ramification 3MORASP was synthesized by the author, and it was used as chemiluminescence reagent. 3-(3′-Methoxyphenyl)-5(2′-sulfonylphenylazo)-rhodanine (3MORASP), first synthesized by the authors, was used as chemiluminescence (CL) reagent. The novel flow path of FI-CL was designed, which made three merged streams of reactants injected into MIP column move through different pathways simultaneously. Fenfluramine was detected based on the reaction of fenfluramine, 3MORASP, and potassium permanganate in an acidic medium. The CL intensity was correlated linearly with the concentration of fenfluramine over the range of 1.0 × 10^?7 to 5.0 × 10^?6 g · mL^?1, and the detection limit was 9.48 × 10^?9 g · mL^?1. The relative standard deviation (RSD) was 2.4% for determination of 1.0 × 10^?6 g · mL^?1 fenfluramine (n = 11). This method was successfully applied to the determination of fenfluramine in weight-reducing tonic.     

Post‐chemiluminescence Method of the Determination of Loperamide Hydrochloride in Human Plasma and Pharmaceutical by Using Dichlorofluorescein as Chemiluminescence Reagent

Abstract

A post‐chemiluminescence (PCL) was observed when loperamide hydrochloride solution was injected into the reaction mixture after the finish of CL reaction of alkaline N‐Chlorosuccinimide (NCS) and dichlorofluorescein. Based on this phenomenon, a simple, sensitive and fast flow injection PCL method was established for the determination of loperamide hydrochloride. The possible mechanism for the PCL reaction was discussed via the investigation of the CL kinetic characteristics, the CL spectra, the fluorescence spectra. The PCL intensity responded linearly to the concentration of loperamide hydrochloride in the range 8.0×10^?10 to 6.0×10^?7 g · ml^?1 with a linear correlation of 0.9995. The detection limit was 4×10^?10 g · ml^?1. The relative standard deviation was 2.4% for 4.0×10^?8 g · ml^?1 loperamide hydrochloride (n=11). This method has been applied to the determination of loperamide hydrochloride in human plasma and pharmaceutical samples with satisfactory results.     

Chemiluminescence Determination of Organophosphorus Pesticides Chlorpyrifos in Vegetable

Abstract

A novel chemiluminescence method for the quantitative assay of the organophosphorus pesticide chlorpyrifos in vegetable samples is presented. The determination is based on the reaction of chlorpyrifos with luminol-H₂O₂ in alkaline medium with sodium chloride being enhancer. Under the optimum conditions, the increased CL intensity was proportional with the concentration of chlorpyrifos in the range of 1.0 × 10^?8 g · ml^?1 ? 1.0 × 10^?6 g · ml^?1 and the detection limit was 3.5 × 10^?9 g · ml^?1 (3σ). The relative standard is less than 3.9% for 5.0 × 10^?7g · ml^?1 chlorpyrifos (n = 7). This method has been successfully applied to the determination of chlorpyrifos residue in vegetable sample. Further study was focused on the mechanism of chlorpyrifos and the possible mechanism was proposed.     

铁氰化钾-钙黄绿素化学发光体系测定酮替芬的研究

发现钙黄绿素可以吸收铁氰化钾氧化酮替芬反应的化学能而产生化学发光, 以钙黄绿素为化学发光试剂, 构建了铁氰化钾-酮替芬-钙黄绿素化学发光体系, 利用此体系建立了测定酮替芬的化学发光分析新方法, 方法的线性范围为2.0×10^－8～6.0×10^－6 g•mL^－1, 检出限为8×10^－9 g•mL^－1, 对浓度为5.0×10^－7 g•mL^－1酮替芬溶液进行11次平行测定的相对标准偏差(RSD)为2.1%. 此法已用于药品中酮替芬含量的测定, 结果与药典测定结果一致. 对化学发光反应的机理也进行了初步的探讨.     

The Determination of Perphenazine by a New Simple Flow‐Injection Chemiluminescence Method

Abstract

A rapid and simple flow‐injection chemiluminescence (CL) method is described for the determination of perphenazine, which is based on the CL intensity that generated from the redox reaction of Ce (IV)-perphenazine in HNO₃ medium is proportional to the perphenazine concentration without any sensitizers. The proposed method allows the determination range within 1.0×10^?7–7.0 ×10^?5 g mL^?1 with a detection limit of 8.0×10^?8 g mL^?1, and it has been successfully applied to the determination of the perphenazine in pharmaceutical tablet compared well with the official method.     

Determination of Baicalin by High Performance Liquid Chromatography Coupling with Flow Injection Chemiluminescence Detection

A new method for the determination of baicalin in Scutellariae Radix extract and its preparations by high performance liquid chromatography (HPLC) coupling with flow injection chemiluminescence detection (FIA‐CL) has been developed. The method was based on the chemiluminescence reaction of potassium permanganate with baicalin in nitric acid medium; the CL intensity can be enhanced by formaldehyde. In this study, the conditions of chemiluminescence and chromatography were examined, and the schematic diagram of the HPLC‐FIA‐CL analyzer was optimized. The analytes were separated on Hypersil RP‐C18 columns (100 × 4.6 mm, I.D., 5 μm) by equality elution with 47:53 (v/v) methanol‐0.3% phosphoric acid as a mobile phase at a flow rate of 0.8 mL·min^?1 and a column temperature of 40 °C. Under the optimum condition, the CL intensity was proportional to the concentration of baicalin over the range of 4.10 × 10^?7 ? 6.15 × 10^?5mol·L^?1. The limit of detection (S/N = 3) was 2.79 × 10^?7mol·L^?1 with the relative standard deviation 2.5% (Cs = 6.15 × 10^?6 mol·L^?1, n = 5). The method has been applied to the determination of baicalin in Scutellariae Radix extract and its preparations, and satisfactory results were obtained.     

A novel chemiluminescence reaction system for the determination of lincomycin with diperiodatonickelate(IV)

A sensitive and high selective chemiluminescence (CL) method was developed for the determination of lincomycin in acid medium using diperiodatonickelate as a reagent. The mechanism leading to luminescence is discussed by comparing the spectra of fluorescence and CL. Relative CL intensity is linear in the range from 8.0 ng mL^?1 to 1.0 µg mL^?1, the limit of detection is 2.5 ng mL^?1 (3σ), and the relative standard deviation is 4.0% at 0.1 µg mL^?1 of lincomycin (n?=?7). The method was successfully applied to the determination of lincomycin in injections, human urine, and in serum samples.     

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.     

Chemiluminescence Determination of Sulpiride in Pharmaceutical Preparations and Biological Fluids Based on KMnO4‐Tween 80 Reaction

Chemiluminescence (CL) of an acidic KMnO₄ system in the presence of Tween 80 was investigated for the determination of sulpiride. Strong CL was recorded when a mixture of sulpiride and Tween 80 was injected into acidic KMnO₄ solution. The experimental parameters affecting the CL intensity were carefully studied using flow injection mode. Under the optimum conditions, the CL intensity was proportional to the concentration of sulpiride in the range of 5.0 × 10⁻⁷ ∼ 1.0 × 10⁻⁴ g mL⁻¹. The detection limit is 1.6 × 10⁻⁷ g mL⁻¹ sulpiride, and the relative standard deviation for 1.0 × 10⁻⁶ g mL⁻¹ sulpiride solution is 1.5% (n = 11). The proposed method has been successfully applied to the determination of sulpiride in tablets and in spiked human plasma and urine samples.     

Flow‐Injection Chemiluminescence Analysis of Cloperastione Hydrochloride

Abstract

A new chemiluminescence (CL) reaction was observed when cloperastine hydrochloride was injected into the reaction mixture after the CL reaction of Ce(IV) and sodium sulfite finished. A new flow injection CL method for the determination of cloperastine hydrochloride was established based on the CL reaction. The relative standard deviation (RSD) for the determination of cloperastine hydrochloride was 1.3% (n=11, c=1.0×10^?6 g/mL). The CL intensity responded linearly to the concentration of cloperastine hydrochloride in the range 2.0×10^?7～2.0×10^?5 g/mL (r=0.9962). The detection limit was 5×10^?8 g/mL cloperastine hydrochloride. The method had been applied to the determination of cloperastine hydrochloride in tablets with satisfactory results.     

Electrochemical Enzyme‐Linked Immunoassay for the Determination of Estriol Using Methyl Red as Substrate

Abstract

A new electrochemical substrate for horseradish peroxidase, methyl red, is reported. In this reaction system, horseradish peroxidase can catalyze the redox reaction of methyl red and H₂O₂. Methyl red exhibits a sensitive voltammetric peak at?0.51 V vs. Ag/AgCl reference electrode, the decrease of the peak current of methyl red is in proportion to the concentration of horseradish peroxidase (HRP). The linear range for determination of horseradish peroxidase is 5.0×10^?8～5.0×10^?7 g mL^?1 and the detection limit is 1.8×10^?8 g mL^?1. The relative standard deviation is 3.3% when 2.0×10^?7 g mL^?1 HRP was sequentially determined 11 times. A voltammetric enzyme‐linked immunoassay method for the determination of estriol was developed, based on this electrochemical system. The linear range for determination of estriol is 1.0～1000.0 ng mL^?1, and the detection limit is 0.33 ng mL^?1. The relative standard deviation for 11 parallel determinations with 200 ng mL^?1 estriol is 4.8%. Some pregnancy serum samples were analyzed with satisfactory results.     

Determination of Melatonin in Rat Pineal Gland and Drug with Flow-Injection Chemiluminescence

A flow-injection chemiluminescence （CL） method for the determination of melatonin based on the CL reaction of melatonin with hydrogen peroxide and sodium hypochlorite （NaOCl） in a basic alkaline solution was developed. The possible CL mechanism has been discussed, and a proposal for the reaction pathway was given that singlet oxygen was clarified to be produced in this reaction system and was responsible for the CL emission. Under the optimized conditions, the linear concentration range of application was 1.0×10^-7-2.5 × 10^-4 moloL-I with a de- tection limit of 5.0 ×10^-8 moloL-1 （S/N= 3）. The relative standard deviation for eight repeated measurements of 1.0×10^-6 mol·L^-1 melatonin was 2.8%. The interferences of several important biological substances, some indole compound, cations and anions were studied. No interference was found for the anions, glucose, starch, most of cations and low concentration （less than 3.0 × 10^-6 mol·L^-1） of some biological substances and indole compound. The method was applied to the determination of melatonin in rat pineal gland and drug with satisfactory results. The sample throughput was 90 injections per hour.     

Determination of Vitamin A in Infant Milk-Based Formulas and Pharmaceutical Formulations Using Flow Injection with Ce(IV)–Na2SO3 Chemiluminescence Detection

A rapid and simple flow injection (FI) method is reported for the determination of vitamin A (retinol) based on its strong enhancing effect on the Ce(IV)–Na₂SO₃ chemiluminescence (CL) reaction in an acidic solution. The effect of key chemical and physical parameters (i.e., reagent concentrations, flow rate, and sample volume) was optimized and potential interferences examined. Under the selected experimental conditions, a linear calibration was obtained between the CL intensity and vitamin A concentration in the range 0.1–8.0 µg mL^?1 (r ²  = 0.9986, n = 8). The limit of detection (3 s x blank) was 0.01 µg mL^?1 retinol (n = 6) and the relative standard deviation (RSD) for 0.25 µg mL^?1 retinol was 2.3% (n = 10) with a sampling rate of 180 h^?1. The method was successfully applied to infant milk-based formulas and pharmaceutical formulations and the results were not significantly different at 95% confidence interval with those obtained by using a spectrophotometric reference method. The possible CL mechanism is also discussed briefly supporting with UV-visible, fluorescence, and CL spectra.     

银（III）配合物-鲁米诺流动注射化学发光新体系测定肾上腺素

儿茶酚胺是一类非常重要的神经递质,在人体的心血管系统、神经系统、内分泌腺、肾脏、平滑肌等组织系统的生理活动中起着广泛的调节作用。肾上腺素为儿茶酚胺的一种,建立灵敏、高效的肾上腺素检测技术具有重要的临床意义。本文将银（Ⅲ）配合物与鲁米诺组成新的流动注射化学发光体系,利用碱性介质中肾上腺素对三价银配合物－鲁米诺化学发光体系有明显的增强效应来测定肾上腺素的含量,并据此建立了高效测定肾上腺素的流动注射化学发光新方法。在优化的条件下,该方法测定肾上腺素的线型范围为1.0×10－9～1.0×10－7 mol L-1,检出限为8.0×10－10 mol L-1,对1.5×10－8 mol L-1肾上腺素11次平行测定,其相对标偏差为2.9％。利用建立的分析方法测定了药物肾上腺素,并对三价银－鲁米诺化学发光新体系测定肾上腺素的反应机理进行了讨论。     

Carbon dots-enhanced luminol chemiluminescence and its application to 2-methoxyestradiol determination

In this study, the fluorescent carbon dots (CDs) of good biocompatibility and low toxicity was prepared by a carbonation route, and a strong enhancement effect of CDs on the luminol-K₃Fe(CN)₆ chemiluminescence (CL) system was observed. 5?±?1?nm CDs were used as catalysts to enhance the reaction sensitivity. In the presence of 2-methoxyestradiol (2-ME), the CL intensity of CDs-luminol-K₃Fe(CN)₆ was significantly inhibited. The relative CL intensity was linearly related to the 2-ME concentration in the range of 1.0?×?10^?9 –1.0?×?10^?7?g?mL^-1 with a lower detection limit of 4.1?×?10^?10?g?mL^?1. As a preliminary application, the highly sensitive method was successfully applied to the determination of 2-ME in both pharmaceutical preparation and serum samples with satisfactory results. The possible mechanism of CL reaction catalyzed by CDs was investigated and the CDs played a role of catalyst in the reaction which could promote the generation of oxygen radicals.

It could be concluded that the enhancement effect on CL by CDs was attributed to the formation of oxygen radicals. The oxidation reaction of luminol was accelerated by oxygen radicals, which led to the enhanced CL emission.     

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.     

N-bromosuccinimide-fluorescein system for the determination of protein by flow injection chemiluminescence

A method for flow injection with chemiluminescence (CL) detection has been developed for the determination of proteins. It is based on the luminescence of the N-bromosuccinimide-fluorescein-protein system, where fluorescein is used as an energy transfer reagent in alkaline medium. The CL of the system is strongly enhanced by hexadecyl trimethyl ammonium bromide. Optimum conditions and possible mechanisms have been investigated. Under optimum experimental conditions, the linear range is from 0.4 to 40 µg·mL^?1 for egg albumin, 0.2 to 20 µg·mL^?1 for bovine serum albumin, and from 1 to 100 µg·mL^?1 for bovine hemoglobin. The detection limits are 37, 62, and 240 ng·mL^?1, respectively.