scholarly journals Determination of Phenylalanine and Tyrosine by Liquid Chromatography/Mass Spectrometry

2003 ◽  
Vol 86 (4) ◽  
pp. 753-758 ◽  
Author(s):  
Samo Andrensek ◽  
Alenka Golc-Wondra ◽  
Mirko Prosek
Keyword(s):  
Food Samples ◽  
Psychomotor Retardation ◽  
Blood Levels ◽  
Liquid Chromatography Mass Spectrometry ◽  
Good Separation ◽  
Ionization Mode ◽  
Reliable Quantification ◽  
Liquid Chromatographic ◽  
Chromatographic Mass

Abstract Phenylketonuria is a common metabolic disorder disease. Those affected appear normal at birth, but without treatment they develop severe psychomotor retardation. Throughout life, they must control their blood levels of phenylalanine (Phe) and consume a diet containing adequate amounts of Phe and tyrosine (Tyr). We have developed a liquid chromatographic/mass spectrometric (LC/MS) method for the quantitative evaluation of Phe and Tyr in food samples. This method takes advantage of the good separation of LC and the selective and reliable quantification provided by MS in the electrospray ionization mode. The LC/MS method is very suitable for the determination of selected amino acids in various matrixes. It is sensitive to levels as low as about 0.30 ppm for Tyr and 0.70 ppm for Phe and robust. Nearly 100 nondietary food samples were analyzed by the developed method.

scholarly journals Liquid Chromatographic/Mass Spectrometric Determination of Desmedipham and Phenmedipham and Their Metabolites in Soil

2001 ◽  
Vol 84 (5) ◽  
pp. 1407-1412 ◽  
Author(s):  
Daniela Perret ◽  
Alessandra Gentili ◽  
Stefano Marchese ◽  
Aldo Marino ◽  
Federica Bruno
Keyword(s):  
Reversed Phase ◽  
Soil Types ◽  
Liquid Chromatography Mass Spectrometry ◽  
Reversed Phase Liquid Chromatography ◽  
Soil Suspension ◽  
Simple Method ◽  
Phase Liquid ◽  
Liquid Chromatographic ◽  
Chromatographic Mass

Abstract A simple method is described for the simultaneous determination of residues of 2 carbamate herbicides (phenmedipham and desmedipham) and related metabolites (m-aminophenol, aniline, and m-toluidine) in soil. The analytes are extracted from spiked soils with methanol. The solvent/soil suspension is centrifuged, and the supernatant is directly injected, without any further cleanup, into a reversed-phase liquid chromatography/mass spectrometry apparatus equipped with a TurboIonSpray interface. The method was tested on 5 soils having different physicochemical properties. Recoveries from the soil types, spiked over the range of 50–200 ppb, were essentially quantitative for each analyte. The detection limits of the method are ≤25 ng/g.

Gas-Liquid Chromatographic and Gas-Liquid Chromatographic-Mass Spectrometric Determination of Fenvalerate and Permethrin Residues in Grasshoppers and Duck Tissue Samples

1981 ◽  
Vol 64 (5) ◽  
pp. 1196-1200
Author(s):  
William L Reichel ◽  
Elizabeth Kolbe ◽  
Charles J Stafford
Keyword(s):  
Liquid Chromatography ◽  
Gel Permeation Chromatography ◽  
Electron Capture Detection ◽  
Gas Liquid Chromatography ◽  
Liquid Chromatography Mass Spectrometry ◽  
Alumina Column ◽  
Tissue Samples ◽  
Liquid Chromatographic ◽  
Chromatographic Mass

Abstract A procedure is described for determining fenvalerate and permethrin residues in grasshoppers and duck tissues. Samples are Soxhlet-extracted with hexane and cleaned up by gel permeation chromatography with an in-line alumina column. Samples are analyzed by gas-liquid chromatography with electron capture detection, and confirmed by gas-liquid chromatography-mass spectrometry. The average recovery from fortified tissues was 97%.

scholarly journals Determination of Disulfiram by Micellar Liquid Chromatography in Illicit Preparations

2011 ◽  
Vol 94 (4) ◽  
pp. 1082-1088 ◽  
Author(s):  
Sandeep-Kumar mourya ◽  
Swati Dubey ◽  
Abhilasha Durgabanshi ◽  
Sudheer Kumar Shukla ◽  
Josep Esteve-Romero ◽  
...  
Keyword(s):  
Direct Injection ◽  
Sodium Dodecyl ◽  
Micellar Liquid Chromatography ◽  
Blood Levels ◽  
Pharmacokinetic Studies ◽  
Optimization Strategy ◽  
Recovering Alcoholics ◽  
Chromatographic Procedure ◽  
Liquid Chromatographic

Abstract Presently, disulfram is used in aversion therapy for recovering alcoholics. It acts by inhibiting aldehyde dehydrogenase, leading to high blood levels of acetaldehyde. A simple direct injection micellar liquid chromatographic procedure was developed to determine disulfram in illicit preparations (ayurvedic, herbal, divine ash, and traditional medicine), as well as inpharmaceuticals and biological samples (urine). After application of a predictive optimization strategy, the proposed method was developed using a 0.1 M sodium dodecyl sulfate-butanol 4% (v/v) buffered to pH 7 as the mobile phase at a flow rate of 1 mL/min, an octyl silyl (C8) 150 mm column, and diode array detection at 248 nm. Under the above conditions, the analysis time was below 8 min. Validation studies were based on U.S. Food and Drug Administration guidelines. The LOD (3 × SD criterion) was 15 ng/mL and LOQ (10 × SD criterion) was 70 ng/mL for disulfram. The intraday and interday precisions were below 3.5%, recoveries were in the range of 97–102%, and robustness was below 3%. The optimized and validated micellar liquid chromatographic method was successfully applied to the determination of disulfram in ayurvedic, herbal, divine ash, and other samples. The procedure developed could also be used in the felds of QC, routine analysis, and pharmacokinetic studies.

Determination of muscarine in human urine by electrospray liquid chromatographic–mass spectrometric

2011 ◽  
Vol 879 (25) ◽  
pp. 2549-2553 ◽  
Author(s):  
Barbora Merová ◽  
Peter Ondra ◽  
Marie Staňková ◽  
Miroslav Soural ◽  
Jan Stříbrný ◽  
...  
Keyword(s):  
Human Urine ◽  
Mass Spectrometric ◽  
Liquid Chromatographic ◽  
Chromatographic Mass
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