Flow-through pore characteristics of monolithic silicas and their impact on column performance in high-performance liquid chromatography

2009 ◽  
Vol 1216 (13) ◽  
pp. 2625-2636 ◽  
Author(s):  
R. Skudas ◽  
B.A. Grimes ◽  
M. Thommes ◽  
K.K. Unger
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
High Performance ◽  
Pore Characteristics ◽  
Flow Through ◽  
Column Performance

High-performance liquid chromatography of quinidine in plasma, with use of a microparticulate silica column.

1978 ◽  
Vol 24 (12) ◽  
pp. 2166-2168 ◽  
Author(s):  
M A Peat ◽  
T A Jennison
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Correlation Coefficient ◽  
High Performance ◽  
Plasma Concentrations ◽  
Internal Standard ◽  
Standard Addition ◽  
Routine Method ◽  
Silica Column ◽  
Column Performance

Abstract We describe a routine method for determining plasma concentrations of quinidine by liquid chromatography. The procedure requires 1.0 ml of plasma (or serum) and involves internal standard addition, extraction with ether, and separation on a column of microparticulate silica. Day-to-day CV (15 days) was less than 5% and no deterioration in column performance has been observed during 12 months. Comparison with a fluorometric procedure gave a correlation coefficient of 0.995.

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.

Development of a Flow-Through Enzyme Immunoassay and Application in Screening Green Coffee Samples for Ochratoxin A with Confirmation by High-Performance Liquid Chromatography

2001 ◽  
Vol 64 (10) ◽  
pp. 1597-1602 ◽  
Author(s):  
L. SIBANDA ◽  
S. DE SAEGER ◽  
T. G. M. BAUTERS ◽  
H. J. NELIS ◽  
C. VAN PETEGHEM
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Enzyme Immunoassay ◽  
Ochratoxin A ◽  
High Performance ◽  
Hplc Method ◽  
Coffee Bean ◽  
Green Coffee ◽  
Penicillium Species ◽  
Flow Through

A flow-through enzyme immunoassay has been developed for the screening of green coffee bean samples for ochratoxin A (OA) and was later used in a survey on OA in green coffee from different countries. The test has a sensitivity of 8 ng/g, and calculated recoveries ranged from 70 to 89% and from 86 to 95% for spiked and naturally contaminated samples, respectively. There were no significant differences in within-day and between-day assay performance (P > 0.05). Green coffee samples (15 Arabica and 7 Robusta) received from an international coffee trader were analyzed for intrinsic fungal contamination, screened for OA, and subsequently confirmed by high-performance liquid chromatography (HPLC). All 22 samples were contaminated by fungal species of the genus Aspergillus, while Penicillium species were isolated from a mere 13.6% of the total number of samples. Isolates were tested for their ability to produce OA, and only 3.9% were positive. There was no correlation between occurrence of OA-producing isolates and levels of OA in contaminated samples. Results of the screening procedure showed that 4 of the 22 samples were contaminated with 8 ng/g or higher. The HPLC method confirmed that the OA levels ranged from 27 to 168 ng/g. A fifth sample, which was shown to be negative during screening, had an OA concentration of 4 ng/g. There were no false negatives or positives recorded, and the flow-through enzyme immunoassay results correlated with those obtained by HPLC.

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