Determination of cocaine concentrations in plasma by high-performance liquid chromatography

1990 ◽  
Vol 36 (8) ◽  
pp. 1436-1439 ◽  
Author(s):  
P Jatlow ◽  
H Nadim
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
High Performance ◽  
Plasma Concentrations ◽  
Internal Standard ◽  
Reversed Phase ◽  
Dilute Acid ◽  
Nitrogen Detection ◽  
Chromatographic Procedure

Abstract We describe a procedure for measuring concentrations of cocaine in plasma by reversed-phase high-performance liquid chromatography, with ion-pairing. The procedure involves solvent extraction followed by back-extraction with dilute acid. The n-propyl ester of benzoylecgonine is used as an internal standard. An evaporation step is not required, and concentrations as low as 5 micrograms/L can be quantified. Plasma concentrations of cocaine determined by high-performance liquid chromatography correlated well with those determined by a previously reported gas-chromatographic procedure with nitrogen detection.

Simultaneous Assay for Six Alkaloids in Opium, Using High-Performance Liquid Chromatography

1975 ◽  
Vol 58 (5) ◽  
pp. 888-897
Author(s):  
Howard W Ziegler ◽  
Thomas H Beasley ◽  
David W Smith
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
High Performance ◽  
Internal Standard ◽  
Dilute Acid ◽  
Reduced Pressure ◽  
Double Beam ◽  
Flow Through ◽  
Chloroform Methanol

Abstract A method is described for the quantitative determination of morphine, codeine, cryptopine, thebaine, papaverine, and narcotine in opium by high-performance liquid chromatography. The alkaloids are isolated from a dilute acid extract by adsorption on an Amberlite XAD-2 resin column and eluted first with methanol and then with chloroform-methanol ( 3+1 ) . After solvent removal by reduced pressure evaporation, the alkaloids are redissolved in chloroformmethanol ( 3+1 ) . The sample solution, plus brucine as an internal standard, is injected onto a Corasil II column and eluted with hexane that is gradient programmed with a solution of chloroform-methanol-diethylamine ( 100+300+1). The absorbances of the separated alkaloids are continuously monitored at 254 nm, using a flow-through ultraviolet double-beam photometer.

scholarly journals Determination of the total tryptophan in food by high performance liquid chromatography combined with enzyme hydrolysis

2019 ◽  
Vol 2 (2) ◽  
pp. 37-43
Author(s):  
Huyen Trang Luu Thi ◽  
Trang Vu Thi ◽  
Ngan Le Viet ◽  
◽  
◽  
...  
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
High Performance ◽  
Limit Of Detection ◽  
Internal Standard ◽  
Standard Addition ◽  
Reversed Phase ◽  
Enzyme Hydrolysis ◽  
Protease Enzyme

High performance liquid chromatography was applied for the determination of tryptophan in food. The sample was hydrolyzed in a duration from 16 to 24 hour by protease enzyme at 50 oC. The extract was separated on the C8 reversed phase column with mobile phase of NaH2PO4 50mM pH 2.3: Methanol (82:18; v/v). The linearity of the method was kept in the range of 0.5 - 50 mg/L. Limit of detection was found to be 4.6 mg/100g. Recovery was determined by standard addition method, giving values of recovery in the range of 97 - 103% and RSD (n = 6) in the range of 0.077 - 2.27%. Internal standard was used to reduce the errors in analysis process and good reproducibility.

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