Flow injection method for the determination of thyroxine by inhibition of glutamate dehydrogenase

Ghous, Tahseen; Townshend, Alan

doi:10.1016/s0003-2670(00)00729-7

Cited by 12 publications

(6 citation statements)

References 16 publications

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“…The proposed FI-CL method for the determination of thyroxine is simple and rapid (100/h sample throughput) as compared to methods described in the literature (20,21). The method has detection limits of 0.08 and 0.1 mg/L for d-and l-thyroxine, respectively.…”

Section: Resultsmentioning

confidence: 91%

“…The limit of detection (3s) is 27 µg/mL and 23 µg/mL for d-and l-thyroxine, respectively, with a sample throughput of <30/h. Another FI-spectrophotometric method has also been reported for the determination of thyroxine (21) to be an inhibitor of glutamate dehydrogenase. The change in NADH absorbance at 340 nm in the presence of the enzyme and thyroxine is measured on-line relative to the percentage inhibition.…”

Section: Introductionmentioning

confidence: 99%

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Determination of thyroxine in pharmaceuticals using flow injection with luminol chemiluminescence inhibition detection

Waseem¹,

Yaqoob²,

Nabi³

2006

Luminescence

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A simple flow injection method is reported for the determination of thyroxine, based on its inhibition effect on luminol-iron(II) chemiluminescence in alkaline medium in the presence of molecular oxygen. The detection limits (2s) for d- and l-thyroxine are 0.08 and 0.1 mg/L, respectively, with a sample throughput of 100/h. The calibration data for d- and l-thyroxine over the range 0.2-1.0 mg/L gives correlation coefficients (r(2)) of 0.9915 and 0.984 with relative standard deviations (RSD; n = 4) in the range 1.2-2.8%. The effects of some organic compounds was studied on luminol-iron(II) CL system for thyroxine determination. The method was applied to pharmaceutical thyroxine tablets and the results obtained (in the range 50.5 +/- 2.0-51.6 +/- 1.2 microg l-thyroxine/tablet) were in reasonable agreement with the value quoted.

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Section: Resultsmentioning

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Determination of thyroxine in pharmaceuticals using flow injection with luminol chemiluminescence inhibition detection

Waseem¹,

Yaqoob²,

Nabi³

2006

Luminescence

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“…Several methods have been developed for the determination of thyroid hormones, including MS 6–9, electrochemistry 10, liquid chromatography 11–17, flow injection and sequential injection coupled with different detections 5, 18–21, chemiluminescence 22 or coupled with immunoassays 23, etc . Although some of them are fairly selective and sensitive, they still present critical shortcomings.…”

Section: Introductionmentioning

confidence: 99%

Simultaneous determination of thyroxine and triiodothyronine in pharmaceutical formulations using capillary electrophoresis with amperometric detection

Sun

Zhao

et al. 2010

J of Separation Science

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A simple, reliable and repeatable method, based on CE with amperometric detection has been developed for the simultaneous separation and determination of thyroxine (T(4)) and 3,3',5-triiodothyronine (T(3)). A carbon disk electrode was used as working electrode in this system and exhibited a good response at 1.05 V (versus Hg/Hg(2)Cl(2), 3 mol/L KCl) for two analytes. The CE separations were investigated in detail. At 21 kV of applied voltage, the two compounds were separated within 11 min in 0.05 mol/L Na(2)B(4)O(7)-NaOH buffer (pH 11.3). And the detection limits were as low as 1.0x10(-7) mol/L for T(4) and 8.5x10(-8) mol/L for T(3) (S/N=3), respectively. The proposed method was applied to analyze T(4) and T(3) in pharmaceutical formulations, and the results were satisfactory.

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“…Beside these, flow injection (FI) methods have also been reported for the determination of thyroxine based on various detection systems. 13,14 The FI-spectrophotometric method has been reported for the determination of thyroxine to be an inhibitor of immobilized glutamate dehydrogenase. 13 The change in NADH absorbance at 340 nm in the presence of an enzyme and thyroxine is measured online related to the percent inhibition.…”

Section: Introductionmentioning

confidence: 99%

“…13,14 The FI-spectrophotometric method has been reported for the determination of thyroxine to be an inhibitor of immobilized glutamate dehydrogenase. 13 The change in NADH absorbance at 340 nm in the presence of an enzyme and thyroxine is measured online related to the percent inhibition. The relative standard deviation is 1.8% for 8.0 × 10 -6 M thyroxine with the limit of detection 9.0 × 10 -7 M. Another FI-chemiluminescence (FI-CL) method based on quenching of the emission intensity by thyroxine has been reported.…”

Section: Introductionmentioning

confidence: 99%

Flow-Injection Determination of Thyroxine Using Immobilized Enzyme with Tris(2,2’-bipyridyl)ruthenium(III) Chemiluminescence Detection

2006

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A flow-injection method is reported for the determination of thyroxine based on its enhancement effect on the tris(2,2′-bipyridyl)ruthenium(III) chemiluminescence reaction in the presence of NADH using immobilized alcohol dehydrogenase purified from baker yeast. The limit of detection (3σ blank) was 5.0 × 10 -8 M with a sample throughput of 80 h -1 . The calibration graph was linear over the range 0.5 -10 × 10 -7 M (r 2 = 0.9988) with the relative standard deviation in the range 1.4 -3.5% (n = 4). The effect of common excipients used in pharmaceutical preparations, some organic compounds and metal ions was studied. The method was applied to pharmaceutical thyroxine tablets, and the obtained results were not significantly different from the amount quoted.

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Flow injection method for the determination of thyroxine by inhibition of glutamate dehydrogenase

Cited by 12 publications

References 16 publications

Determination of thyroxine in pharmaceuticals using flow injection with luminol chemiluminescence inhibition detection

Determination of thyroxine in pharmaceuticals using flow injection with luminol chemiluminescence inhibition detection

Simultaneous determination of thyroxine and triiodothyronine in pharmaceutical formulations using capillary electrophoresis with amperometric detection

Flow-Injection Determination of Thyroxine Using Immobilized Enzyme with Tris(2,2’-bipyridyl)ruthenium(III) Chemiluminescence Detection

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