The use of carbon paste electrode in the direct voltammetric determination of tryptophan in pharmaceutical formulations

Fiorucci, Antonio Rogério; Cavalheiro, Éder Tadeu Gomes

doi:10.1016/s0731-7085(01)00711-7

Cited by 125 publications

(53 citation statements)

References 23 publications

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“…For the determination of acid dissociation constants of the ligand L an aqueous solution (0.3 mM) of the protonated ligand was titrated with 0.03 M NaOH at 25˚C under nitrogen atmosphere and ionic strength of 0.1 M, NaNO 3 . For the determination of binary (one ligand and Cu 2+ ) and ternary systems (Cu 2+ , one of the other L ligand (Har) and L), the ratios used were 1:1:1, Cu(II) : L: Har, 0.3 mM.…”

Section: Methodsmentioning

confidence: 99%

Equilibria and Stability in Glycine, Tartrate and Tryptophan Complexes, Investigation on Interactions in Cu(II) Binary and Ternary Systems in Aqueous Solution

Sajadi

2014

OJINM

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Section: Methodsmentioning

confidence: 99%

Equilibria and Stability in Glycine, Tartrate and Tryptophan Complexes, Investigation on Interactions in Cu(II) Binary and Ternary Systems in Aqueous Solution

Sajadi

2014

OJINM

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“…Among essential amino acids, TRP is of most considerable significance due to its diversity of biological tasks in human body [2]. It is a vital component of proteins and crucial in human diet for setting up a positive nitrogen balance [3]. It produced from proteins during digestion by the action of proteolytic enzymes.…”

Section: Introductionmentioning

confidence: 99%

“…The analytical methods used for the determination of TRP content in biological media, in food or in pure form include titrimetry [10], capillary electrophoresis [11][12][13], voltammetry [3,14,15], chemiluminescence (CL) [16][17][18], amperometry [19,20], polarography [21], high-performance liquid chromatography (HPLC) [22][23][24][25][26], fluorescence spectroscopy and spectrophotometric method [27,28]. Among these methods, titrimetry is the easiest and straightforward, but it is insensitive and only the amino acids of samples with more than mM concentration can be precisely estimated [10].…”

Section: Introductionmentioning

confidence: 99%

An Improved High Performance Liquid Chromatographic Method for Tryptophan Analysis in Rat Brain Administrated by Seaweed

Mustafa¹,

Hashim²,

Khaliq³

et al. 2014

J Anal Bioanal Tech

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IBrain functions can be affected by the dietary precursors of neurotransmitters. Tryptophan (TRP) is the precursor of serotonin (5-Hydroxytryptamine; 5-HT) neurotransmitter that plays an important role in sleeping, mood, eating behavior, consciousness and cognitive functions. Present study describes the estimation of tryptophan in rat brain by aqueous-reverse-phase high performance liquid chromatography. Estimation was carried out on a shim pack end-capped C-18 column using water as mobile phase (pH=9 adjusted by addition of 0.1 mM NaOH) at a flow rate of 1 ml min-1. Eluents were monitored at 273 nm by an ultra-violet detector. The method was linear (R2=0.9973) and the limit of detection (LOD) and limit of quantification (LOQ) were 4.3920 and 13.3091 ng ml-1, respectively. The developed HPLC method is simple convenient, reliable and economical for the estimation of tryptophan in rat brain. In the present study, Albino Wistar male rats were randomly divided into two groups control and seaweeds treated rats. Seaweeds (Jolyna Laminiriodes) were orally given to test rats at a dose of 200 mg kg-1 whereas control rats were given vehicle for 28 days. After 28 days of treatment, rats were decapitated and its brain samples were taken out for the estimation of TRP. Current study observed increased in TRP levels in the brain samples of seaweed treated rats as compared to control rats. Therefore present study suggested the use of seaweeds in the treatment of disorders caused by TRP depletion. By this newly developed method for the estimation of TRP, effect of various drugs on TRP levels in the brain could be studied.

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“…Mass spectrometry is also becoming increasingly more popular because of its sensitivity. 11,12 Additionally, enzyme-modified sensors, 13,14 luminescence systems, 15,16 and electrochemical methods 17,18 have also been proposed.…”

Section: Introductionmentioning

confidence: 99%

Metal Ion‐Assisted Infrared Optical Sensor for Selective Determination of Tryptophan in Urine Samples

Huang

Cheng

Yang

2011

J Chinese Chemical Soc

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In this study, a simple infrared chemical sensor was developed for the selective detection of tryptophan in biological fluids. This sensor was capable of trapping tryptophan molecules through the formation of relatively stable metal ion complexes on the surface of the sensing element. A proline-modified sensing phase was immobilized on the surface of the internal reflection element. With the assistance of appropriate metal ions, tryptophan molecules were selectively attracted nearby the evanescent field such that analytical signals were generated. Factors that affected the chemical equilibria in this detection system were examined including the species and concentration of metal ion, the pH of the sample solution, and the concentration of the chelating agent. Among the examined metal ions, nickel provided the best selectivity toward the detection of tryptophan as a result of its extremely high formation constant with tryptophan. Under the optimal conditions, the detected signals were related linearly (R 2 > 0.99) to concentrations of tryptophan up to 600 mM. Based on three times the baseline variation of blank samples, the detection limit was ca. 5 mM. From a study of possible interfering agents-metal ions and organic species-in the sample solution, the recoveries of tryptophan were greater than 95%.

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The use of carbon paste electrode in the direct voltammetric determination of tryptophan in pharmaceutical formulations

Cited by 125 publications

References 23 publications

Equilibria and Stability in Glycine, Tartrate and Tryptophan Complexes, Investigation on Interactions in Cu(II) Binary and Ternary Systems in Aqueous Solution

Equilibria and Stability in Glycine, Tartrate and Tryptophan Complexes, Investigation on Interactions in Cu(II) Binary and Ternary Systems in Aqueous Solution

An Improved High Performance Liquid Chromatographic Method for Tryptophan Analysis in Rat Brain Administrated by Seaweed

Metal Ion‐Assisted Infrared Optical Sensor for Selective Determination of Tryptophan in Urine Samples

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