Chemiluminescence flow system for the determination of sulfite

A novel chemiluminescence(CL) flow system for sulfite is described based on electrostatically immobilized luminol on an anion exchange column. Sulfite is detected by the CL reaction with luminol bleeding from the column by hydrolysis. The calibration graph is linear in the range 3 × 10^–7 to 1 × 10^–5 mol/L, and the detection limit is 1 × 10^–7 mol/L. Interfering metal ions co-existing in sample solutions could be effectively eliminated on-line by an upstream cation exchanger. A complete analysis could be performed in 1 min with a relative standard deviation of less than 5%. The system could be reused for over 50 h and has been applied successfully to the determination of sulfur dioxide in air.     

Quantitation of Meclizine Dihydrochloride in Serum by Reversed Phase Ion Pair High Performance Liquid Chromatography

Abstract

A specific and sensitive HPLC method has been developed for the assay of meclizine dihydrochloride in dog serum using an internal standard technique with a single step extraction. The extracts are injected into a reversed phase ion pair HPLC system using a solvent containing camphorsulfonate as paring anion. The detection limit is 5 ng/ml and the range of linearity is 5–250 ng/ml. The method has been used to quantitate meclizine dihydrochloride levels in bioavailability and pharmacokinetic studies in dogs.     

Chromatography of Uranium on High-Performance Ion Exchangers

Abstract

The potential of high-performance liquid chromatography (HPLC) for the determination of U(VI) in ground waters and urine has been examined under a variety of HPLC experimental conditions. Conventional cross-linked and bonded-phase ion exchangers, both cation and anion, were studied with aqueous mobile phases containing tartrate, citrate, or α-hydroxyisobutyrate. The best chromatography was obtained on bonded-phase cation exchangers with an α-hydroxyisobutyrate eluent. The metal ions were detected either by visible spectrophotometry after a post-column reaction with a complexing reagent, or with a polarographic detector. Dectection after post-column reaction gave the best sensitivity; the detection limit (2 × baseline noise was 6 ng or 60 ng.ml^?1 for 100 μl samples. In-line trace enrichment was used to decrease detection limits and linear calibration curves were observed in the ranges studied; 0.5 to 50 ng.mL^?1 for ground waters and 25 to 400 ng.mL^?1 for artificial urine.     

Determination of cobalt at picogram levels by high-performance liquid chromatography with chemiluminescence detection

A simple cation-exchange chromatographic system was used to separte cobalt from other metal ions. The cobalt thus separated was detected by the luminol chemiluminescence reaction using a spectrofluorimeter as the detector. A 3σ detection limit of 0.5 ng l^?1 was achieved, without the need for preconcentration, with a 200-μl sample. The system provided a linear analytical working range from 5 ng l^?1 to 10 μg l^?1. The cobalt content of a rice flour certified reference material was determined using the system and gave good agreement with the certificate value.     

High Performance Liquid Chromatographic Determination of Neomycin in Milk Using a Hisep Column

Abstract

A high performance liquid chromatographic (HPLC) method for the determination of neomycin in milk is described. Milk is passed directly through an amberlite CG-50 ion exchange resin column, and the neomycin which is retained on the column is derivatized with ortho-phthalaldehyde (OPA) reagent. The derivatized neomycin is eluted from the column with potassium borate buffer/methanol and analyzed by HPLC. A HISEP HPLC column with fluororoetric detection was used. Recoveries ranged from 94 to 102% in samples fortified between 0.1 to 5ppra levels. The detection limit is 50ppb.     

Flow-injection chemiluminescence determinations for human blood lead using controlled reagent release technology

A flow-through CL method for the determination of lead combined with controlled-reagent-release technology has been developed. Chemiluminescence (CL) reagents luminol and potassium permanganate were immobilized on anion exchange resin by electrostatic interaction. Lead ion was determined by its enhancing effect on the CL reaction between luminol and potassium permanganate. Both luminol and potassium permanganate were eluted from the anion exchange resin column by sodium phosphate solution. The linear range of the system was 10 μg mL^?1, and the detection limit was 5?×?10^–9 g mL^?1 lead (3σ). A complete analysis could be performed in 1 min with a relative SD 3.2% (1.0?×?10^–7 g mL^?1, n?=?9). The column shows remarkable stability and can be reused over 350 times and 21 days. The method has been applied to determine lead in human blood samples.     

Chemiluminescence flow system for the determination of sulfite

A novel chemiluminescence(CL) flow system for sulfite is described based on electrostatically immobilized luminol on an anion exchange column. Sulfite is detected by the CL reaction with luminol bleeding from the column by hydrolysis. The calibration graph is linear in the range 3 × 10^–7 to 1 × 10^–5 mol/L, and the detection limit is 1 × 10^–7 mol/L. Interfering metal ions co-existing in sample solutions could be effectively eliminated on-line by an upstream cation exchanger. A complete analysis could be performed in 1 min with a relative standard deviation of less than 5%. The system could be reused for over 50 h and has been applied successfully to the determination of sulfur dioxide in air. Received: 21 October 1997 / Revised: 23 February 1998 / Accepted: 26 February 1998     

Simultaneous quantification of catecholamines in rat brain by high‐performance liquid chromatography with on‐line gold nanoparticle‐catalyzed luminol chemiluminescence detection

A new method based on high‐performance liquid chromatography (HPLC) coupled with on‐line gold nanoparticle‐catalyzed luminol chemiluminescence (CL) detection was developed for the simultaneous quantitation of catecholamines in rat brain. In the present CL system, gold nanoparticles were produced by the on‐line reaction of H₂O₂, NaHCO₃?Na₂CO₃ (buffer solution of luminol) and HAuCl_4. Norepinephrine (NE), epinephrine (EP) and dopamine (DA) could strongly enhance the CL signal of the on‐line gold nanoparticle‐catalyzed luminol system. The UV?visible absorption spectra and transmission electron microscopy studies were carried out, and the CL enhancement mechanism was proposed. Catecholamines promoted the on‐line formation of more gold nanoparticles, which better catalyzed the luminol–H₂O₂ CL reaction. The good separation of NE, EP and DA was achieved with isocratic elution using a mixture of methanol and 0.2% aqueous phosphoric acid (5:95, v/v) within 8.5 min. Under the optimized conditions, the detection limits, defined as a signal‐to‐noise ratio of 3, were in the range of 1.32–1.90 ng/mL, corresponding to 26.4?38.0 pg for 20 μL sample injection. The recoveries of catecholamines added to rat brain sample were >94.6%, with the precisions <5.5%. The validated HPLC?CL method was successfully applied to determine NE and DA in rat brain without prior sample purification. Copyright © 2014 John Wiley & Sons, Ltd.     

Chemiluminescence flow system for the determination of ammonium ion

A novel chemiluminescence (CL) system for ammonium ion combined with flow-injection analysis is presented in this paper. It is based on the CL reaction between luminol, immobilized electrostatically on an anion-exchange column, and chlorine electrochemically generated on-line via a platinum electrode from hydrochloric acid in a coulometric cell. Ammonium ion reacts with chlorine and decreases the observed CL intensity. The system responds linearly to ammonium ion concentration in the range 1.0-100 muM, and the detection limit is 0.4 muM. A complete analysis, including sampling and washing, could be performed in 1 min with a relative standard deviation of <6.0%. The system is stable for over 500 determinations and has been applied successfully to the determination of ammonium ion in rainwater samples.     

Chemiluminescence - High Performance Liquid Chromatography of Phosphatidylcholine Hydroperoxide

Abstract

A chemiluminescence - high performance liquid chromatography (CL-HPLC) system was developed for the hydroperoxide-specific detection of phosphatidylcholine hydroperoxide. In this system, chemiluminescence detector was equipped with normal phase HPLC. Luminol-cytochrome c solution was used as the hydroperoxide-specific luminescent reagent. A detection limit of 7 nmol hydroperoxide-O₂ of phosphatidylcholine hydroperoxide could be achieved.     

Ultrasensitive chemiluminescence detection of aM vanadium(IV) by capillary electrophoresis

Ultrasensitive chemiluminescence (CL) detection of aM vanadium(IV) in capillary electrophoresis (CE) is first reported. In this work, inclusion of the luminol in the electrophoretic carrier electrolyte avoids the loss of light signal that occurs when luminol and hydrogen peroxide are mixed in advance, as in the conventional method in CE-CL detection. The detection limit (S/N ratio=3) for V(IV) is 2.4×10⁻¹⁷ M (24 aM), which has been improved by a factor of 10⁴ as compared with that of the most sensitive metal ion detection (Co²⁺ 0.5 pM) reported previously. In addition, the separation of V(IV) and V(V) has been performed successfully.     

Flow-Injection Enzyme Immunoassay for Human IgG by Using Enhanced Chemiluminescence Reaction for Horseradish Peroxidase Label Quantitation

Abstract

A flow-injection sandwich enzyme immunoassay for human IgG as model antigen by using horseradish peroxidase as label, polystyrene beads as solid support, and the enhanced chemiluminescence reaction for peroxidase quantitation is described. the kinetics of antigen—immobilized antibody interaction has been studied and the quantitative time-concentration ranges of reactions have been estimated. Each of the two immunochemical steps of analysis have been pursued in the kinetic regime. the time for each immunochemical step was reduced to 2–3 min. the enhanced luminescent reaction involving luminol and p-iodophenol as substrates was used to detect the peroxidase label. the conditions for chemiluminescent reaction were optimized. the detection limit for peroxidase in a 3 min assay was 5–10^?16 moles/tube. the detection limit for IgG, in the developed immunoassay, is 10^?9 M, the overall time of the assay being 5–10 min.     

Flow-Injection Determination of Glucose by a Photoinduced Chemiluminescent Reaction

Abstract

A flow-injection procedure for the photochemical determination of glucose has been developed. The method is based on the photo-oxidation of glucose sensitized by 9,10-anthraquinone-2.6-disulfonate (disodium salt). The hydrogen peroxide formed in the photochemical reaction was measured by means of the chemiluminescent reaction with luminol and hematin. A linear calibration graph was obtained over the range 2.0x10^?6-8.5 x 10^?5 mol L^?1. The method was applied to determining glucose in blood serum, urine and fruit juices.     

Separation of Selected Transition Metal Ions and Divalent Metal Ions by HPLC Using UV-VIS Detection

Abstract

The use of ethylenediaminetetraacetic acid, disodium salt, (pH 3-5) has been investigated as an eluant for the separation and detection of nanogram levels of selected divalent and trivalent metal ions. The effect of pH and eluant concentration upon the retention times and resolution of the system are given and the ability to alter the eluant characteristics to optimize the chromatographic results in different situations will be discussed. The method is less complicated than the method frequently used for transition metal ion determinations which uses a post-column derivitization reagent. This method is applicable to a wider range of metal ions and provides detection limits which are generally within two orders of magnitude of the post-column derivitization method.     

In Vitro Monitoring of Picogram Levels of Captopril in Human Urine Using Flow Injection Chemiluminescence with Immobilized Reagent Technique

Abstract

A flow‐injection procedure for detection of captopril using a Co²⁺‐captopril complex formed on line based enhancement of luminol and dissolved oxygen chemiluminescence is described. The chemiluminescence reagents, luminol and Co²⁺, were both immobilized on ion exchange resin in the flow injection system. When captopril solution flowed through the immobilized Co²⁺ column, the Co²⁺‐captopril (1:2) complex formed on line could greatly enhanced the chemiluminescence intensity generated from the reaction between luminol and dissolved oxygen. The increment of chemiluminescence emission was correlated with the captopril concentration in the range from 7 to 1000 pg mL^?1, and the detection limit was 2 pg mL^?1 (3σ). One analysis cycle, including sampling and washing, could be accomplished in 0.5 min with relative standard deviations of less than 3.0% (n=11). The proposed method was applied directly in the assay of human urine without any pretreatment and it was found that the captopril concentration reached its maximum after being administrated orally for 1.5 hours, with the mean excretion ratio in 6.5 hours of 54.3% in the body of volunteers. The possible chemiluminescence mechanism was discussed.     

Ultramicro Analysis of Reducing and Non-Reducing Sugars by Liquid Chromatography

Abstract

A post-column detection system for ultramicro amount of sugars has been developed using taurocyamine as the labelling reagent. Less than 10 pmol of reducing sugars were determined by this HPLC system. Non-reducing sugars were detected by the addition of periodate to the reagent.

Modification of the reaction reagent components made this detection system feasible to apply to various methods for separation of carbohydrates using pure water, acetonitrile/water mixtures, borate buffer or aqueous sodium hydroxide as the eluent.     

Determination of lipid hydroperoxides in low density lipoprotein from human plasma using high performance liquid chromatography with chemiluminescence detection

A high performance liquid chromatographic system with chemiluminescence detection (HPLC-CL) was used for determining phospholipid hydroperoxides in human plasma low density lipoprotein (LDL). This system involved separation of phospholipids from LDL-total lipids with normal phase silica gel HPLC and post-column detection of hydroperoxide-dependent chemiluminescence produced by luminol oxidation during the reaction of hydroperoxide with cytochrome c-haeme. By using HPLC-CL, we could detect phosphatidylcholine hydroperoxide (PCOOH) in human plasma LDL, and the LDL-PCOOH concentration was significantly higher in patients with atherosclerosis and hyperlipidemia than that of healthy volunteers. The LDL-PCOOH level was proportional to the plasma total cholesterol concentration.     

Chemiluminescence Flow Injection Analysis of Menadione Sodium Bisulfite Based on Luminol Reaction

ABSTRACT

A chemiluminescence(CL) flow system is described for the determination of menadione sodium bisulfite based on its repression on the chemiluminescence(CL) emission produced upon mixing a hexacyanoferrate(III) solution with an alkaline luminol solution in the absence of co-oxidizer. The system responds linearly to menadione sodium bisulfite concentration in the range 0-1 μg/mL with a detection limit (3σ) of 0.01 μg/mL. Relative standard deviation (RSD) of 0.16% for 0.4 μg/mL menadione sodium bisulfite (n=11). The system has been successfully applied to the determination of menadione sodium bisulfite in tablets and injections.     

On the Effect of Hydrogen Peroxide on the Flow‐Injection Determination of Platinum Based on Luminol Chemiluminescent Reaction

Abstract

A flow‐injection chemiluminescent (CL) method for the determination of trace amounts of Pt(IV) based on the oxidation reaction of luminol in alkaline solution is proposed. The effect of Pt(IV) on the oxidation of luminol was studied in the absence and in the presence of hydrogen peroxide. The positive effect of hydrogen peroxide as well as chloride ions on the sensitivity of measurements was observed. The developed method is characterized by a low limit of detection of Pt (LOD=0.06 ng mL^?1) and good reproducibility (RSD=2.2%). The addition of hydrogen peroxide to the reaction medium resulted in decreasing of platinum detection limit to 0.03 ng mL^?1.     

Enzymatic Assay of Oxalate in Urine by Flow Injection Analysis Using Immobilized Oxalate Oxidase and Chemiluminescence Detection

Abstract

A flow injection analysis (FIA) method for the assay of oxalate in urine samples is described, which utilizes an incorporated column reactor of immobilized oxalate oxidase. The hydrogen peroxide generated is detected by chemiluminescence via reaction with luminol and hexacyanoferrate(III). Special empasis is placed on the role of L-ascorbic acid, which has been claimed to constitute the most serious interference in these types of assays. The possible elimination af this constituent by addition of sodium nitrite, as previously used in batch procedures, did not improve the selectivity of the approach. The FIA approach described, which has a detection limit (3[sgrave]) of 34 μM in undiluted urine samples and allows a sampling frequency of ca. 55 s/h, is shown to offer itself as convenient and rapid means for screening purposes.