Ultrasonic-assisted derivatization reaction of amino acids prior to their determination in urine by using single-drop microextraction in conjunction with gas chromatography

Fiamegos, Yiannis C.; Nanos, Christos G.; Stalikas, Constantine D.

doi:10.1016/j.jchromb.2004.09.013

Cited by 52 publications

(23 citation statements)

References 35 publications

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“…The other reason is that by adding the NaCl to the solution, the viscosity of the bulk solution is increased and results in a decrease in the diffusion rate of analytes from the bulk solution to the organic phase [46]. Finally, the presence of granules of sodium chloride, which cause instability in the droplet, is another reason for this reduction [47]. It is obvious that with increasing the salt concentration, the analytical signal decreases.…”

Section: Ionic Strengthmentioning

confidence: 99%

Separation and Determination of Amitriptyline and Nortriptyline in Biological Samples Using Single-Drop Microextraction with GC

Yazdi

Razavi

2011

Chromatographia

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The combination of liquid phase microextraction (LPME) based on a single drop and gas chromatography flame ionization detector (GC-FID) was used for separation and determination of amitriptyline and nortriptyline in human plasma and urine samples. The sample solution was kept alkaline (pH 12), then a microdrop of organic solvent (isooctane) was suspended in the donor solution; after extraction, the organic microdrop was injected into the GC-FID. Experimental LPME conditions were optimized. Finally, the enrichment factors (89.5-139.0), the relative standard deviation (RSD%, n = 5) 1.1-8.5, linearity ranges (0.05-20 lg mL -1 ), and the limits of detections (0.01, 0.02 lg mL -1 ) for selected drugs were evaluated.

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Section: Ionic Strengthmentioning

confidence: 99%

Separation and Determination of Amitriptyline and Nortriptyline in Biological Samples Using Single-Drop Microextraction with GC

Yazdi

Razavi

2011

Chromatographia

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“…Selenoamino acid standards and extracts from selenium supplements were derivatized with ethylchloroformate (ECF) using procedures developed by Hušek [60] and reported by a number of workers [61][62][63][64]. Derivatized standard solutions (1000 ppm) were prepared by treating 100 L of the 10,000 stock solution with 1 mL of water-ethanol-pyridine mixture (60:32:8, by volume) and 50 L of ECF and the mixture shaken, venting off any evolved CO 2 gas.…”

Section: Derivatization For Gc Analysismentioning

confidence: 99%

Speciation of selenium dietary supplements; formation of S-(methylseleno)cysteine and other selenium compounds

Amoako

Uden

Tyson

2009

Analytica Chimica Acta

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a b s t r a c tSpeciation of selenium is of interest because it is both essential and toxic to humans, depending on the species and the amount ingested. Following indications that selenium supplementation could reduce the incidence of some cancers, selenium-enriched yeast and other materials have been commercialized as supplements. Most dramatically however, the SELECT trial that utilized l-selenomethionine as the active supplement was terminated in 2008 and there is much debate regarding both the planning and the results of efficacy studies. Further, since dietary supplements are not regulated as pharmaceuticals, there are concerns about the quality, storage conditions, stability and selenium content in selenium supplements. Enzymatic hydrolysis enabled selenium speciation profiles to be obtained by high performance liquid chromatography with inductively coupled plasma mass spectrometry (HPLC-ICP-MS) and following derivatization gas chromatography with atomic emission detection (GC-AED). Coated fiber solid phase microextraction (SPME) was used to extract volatile selenium species for determination by GC-AED and GC-MS. Similar speciation patterns were observed between yeast-based supplements subject to extended storage and those heated briefly at elevated temperatures. All the yeast-based supplements and one yeast-free supplement formed S-(methylseleno)cysteine on heating. Evidence was obtained in support of the hypotheses that S-(methylseleno)cysteine is formed from a reaction between dimethyldiselenide and cysteine or cystine.

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“…Metabolic profiling analysis of multiple AAs require the use of high-resolution chromatography, mainly by high-resolution capillary gas chromatography (GC) (12)(13)(14)(15) and high-performance liquid chromatography with fluorescence (7,10,16) or electrochemical detections (4,6,9,11,16). GC combined with mass spectrometry (MS) has been more preferred because of its inherent high resolving power, high sensitivity and positive peak confirmation.…”

Section: Introductionmentioning

confidence: 99%

Altered free amino acid levels in brain cortex tissues of mice with Alzheimer's disease as their N(O,S)-ethoxycarbonyl/tert-butyldimethylsilyl derivatives

Paik

Cho²,

Mook‐Jung³

et al. 2008

BMB Reports

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Ultrasonic-assisted derivatization reaction of amino acids prior to their determination in urine by using single-drop microextraction in conjunction with gas chromatography

Cited by 52 publications

References 35 publications

Separation and Determination of Amitriptyline and Nortriptyline in Biological Samples Using Single-Drop Microextraction with GC

Separation and Determination of Amitriptyline and Nortriptyline in Biological Samples Using Single-Drop Microextraction with GC

Speciation of selenium dietary supplements; formation of S-(methylseleno)cysteine and other selenium compounds

Altered free amino acid levels in brain cortex tissues of mice with Alzheimer's disease as their N(O,S)-ethoxycarbonyl/tert-butyldimethylsilyl derivatives

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