Voltammetric electrochemical detection for normal-phase high-performance liquid chromatography

Thomas, Michael B.; Last, Thomas A.

doi:10.1021/ac00170a036

Cited by 19 publications

(2 citation statements)

References 20 publications

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“…2-Thiouracil, its derivatives and methimazole are thyreostatic drugs used in the treatment of hyperthyroidism 1 , and also to increase the growth rate in animals for human consumption with harmful consequences for human health. These drugs have been determined in pharmaceuticals by titrimetry, 2,3 spectrophotometry, [4][5][6][7] nuclear magnetic resonance, 8 electroanalytical methods [9][10][11] and high-performance liquid chromatography (HPLC), 12 and in biological samples including flour, fluids and tissues by a spectrophotometric kinetic procedure, 7 thin-layer chromatography, 13,14 gas chromatography, 15,16 HPLC 12,17 and radioimmunoassay. 18 Capillary zone electrophoresis has been used to determine thyreostatics in human, bovine and horse urine.…”

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confidence: 99%

Determination of thyreostatics in animal feed by micellar electrokinetic chromatography

Esteve‐Romero

Escrig-Tena²,

Simó‐Alfonso³

et al. 1999

Analyst

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The determination of the thyreostatics 2-thiouracil, its derivatives (4-methyl-2-thiouracil, 4-propyl-2-thiouracil and 4-phenyl-2-thiouracil) and methimazole in manufactured dried animal feed by micellar electrokinetic chromatography (MEKC) is described. A 99 +/- 5% extraction yield at the 20 micrograms g-1 level (n = 8) was achieved by shaking the milled fodder with methanol-1 M NaOH (80 + 20). Aliquots of the supernatant were injected in a 75 microns x 33.5 cm uncoated silica capillary using pressure; separation was performed at 23 degrees C with 15 kV (positive polarity) in a background electrolyte (BGE) containing 40 mM sodium dihydrogenphosphate, 50 mM sodium dodecyl sulfate and 15 mM Tween 20 at pH 9. When the surfactants were added to the BGE, all the thyreostatics were well resolved and the fodder extracts showed lower backgrounds. The peaks appeared within the 2.25-5.2 min range with efficiencies in the 2.5 x 10(4)-8 x 10(4) range; methimazole appeared in the vicinity of the electroosmotic migration time. Calibration curves were linear within the studied range (20-200 micrograms ml-1, r2 > 0.998). Limits of detection in the extracts of spiked fodder samples ranged from 0.25 to 0.4 microgram ml-1, which corresponded to 0.6-1.0 microgram of drug per gram of fodder. Peak area repeatabilities were about 4% at the 20 micrograms ml-1 level.

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confidence: 99%

Determination of thyreostatics in animal feed by micellar electrokinetic chromatography

Esteve‐Romero

Escrig-Tena²,

Simó‐Alfonso³

et al. 1999

Analyst

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“…(13) (14) (15) where (RQ*H,O) is the photosolvation adduct of BQ. The mechanism is based on the photosolvation of excited BQ molecules to form adducts with water, which subsequently react with a ground state BQ to produce radical intermediates.…”

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confidence: 99%

Photoelectrochemical detection of alcohols

Barisci

Wallace

1992

Electroanalysis

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A method for photoelectrochemical detection of alcohols in liquid chromatography and flow injection analysis based on the reaction of the analyte with a photosensitized quinone (benzoquinone) has been developed. Irradiation of the flowing solution and electrochemical detection of the generated photoproduct is carried out within the detector flow cell. Pulsed amperometric detection produced higher sensitivities than conventional potentiostatic amperometry. Samples of vodka and beer were successfully analyzed using the proposed method.

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Cross-linked Polyvinyl Alcohol pH Sensitive Membrane Immobilized with Phenol Red for Optical pH Sensors

et al. 2006

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An optical pH sensitive membrane for optical pH sensors has been developed by covalently immobilizing phenol red on optical transparent cross-linked polyvinyl alcohol (PVA) membrane surfaces. The phenol red was first reacted with acrylamide to form a product of acrylamide grafted phenol red (AAGP), then the AAGP was covalently immobilized to the PVA membrane via surface grafting-polymerization using Fe 2＋ /H 2 O 2 as initiator. The performance of the pH sensitive membrane was investigated and the results showed that the pH sensitive membrane has some features including a linear response scope from pH 6.5 to 8.5 closed with phenol solution, a rapid response time (＜20 s), good reproducibility, reversibility, excellent stability and easiness of fabrication. These show that the pH sensitive membrane can be used as a sensitive layer for optical pH sensor.

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Voltammetric electrochemical detection for normal-phase high-performance liquid chromatography

Cited by 19 publications

References 20 publications

Determination of thyreostatics in animal feed by micellar electrokinetic chromatography

Determination of thyreostatics in animal feed by micellar electrokinetic chromatography

Photoelectrochemical detection of alcohols

Cross-linked Polyvinyl Alcohol pH Sensitive Membrane Immobilized with Phenol Red for Optical pH Sensors

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