Liquid-chromatographic analysis for serum theophylline in less than 70 seconds.

1982 ◽  
Vol 28 (4) ◽  
pp. 687-689 ◽  
Author(s):  
P M Kabra ◽  
L J Marton

Abstract We describe a sensitive, specific, and very fast liquid-chromatographic assay for serum theophylline, involving a commercially available high-speed reversed-phase column and a micro-flow-cell-equipped detector. Each analysis requires only 100 microL of serum (as little as 25 microL may be used when necessary), and chromatography is complete in less than 70 s. Analytical recovery of theophylline added to serum ranged from 97 to 102%. Between-run precision (CV) ranged from 2.1 to 3.5%. The lower limit of detection for theophylline is 0.5 mg/L, and linearity extends to 50 mg/L. Numerous drugs and xanthine metabolites tested do not interfere.

1983 ◽  
Vol 29 (3) ◽  
pp. 473-476 ◽  
Author(s):  
P M Kabra ◽  
M A Nelson ◽  
L J Marton

Abstract We describe a sensitive, specific, and very fast liquid-chromatographic assay for simultaneously determining five anticonvulsants (ethosuximide, primidone, phenobarbital, phenytoin, and carbamazepine) by using commercially available 5- or 3-microns particle size reversed-phase columns and a microflow-cell-equipped ultraviolet detector. The anticonvulsant drugs are extracted from 200 microL of serum containing 50 mg of cyclopal per liter as an internal standard, by elution from a Bond-Elut (Analytichem International, Harbor City, CA 90710) column with 300 microL of methanol. A 5-microL aliquot of the eluate is applied to an analytical column and eluted with a mobile phase of acetonitrile/methanol/phosphate buffer, 20 mmol/L, pH 3.7 (13.5/35/51.5 by vol), at a flow rate of 3.0 mL/min and at 50 degrees C. Detection is at 210 or 195 nm. The chromatography is complete in less than 2.5 min with the 5-microns-particle column, and in less than 1.4 min with the 3-microns-particle column. The sensitivity of the method for all drugs is less than 1 mg/L. Analytical recovery of drugs added to serum ranged from 92 to 109% for concentrations up to 200 mg/L. Between-run precision (CV) ranged from 1.3 to 4.1%.


2007 ◽  
Vol 57 (2) ◽  
pp. 231-239 ◽  
Author(s):  
Mohamed Rizk ◽  
Fawzia Ibrahim ◽  
Mohamed Hefnawy ◽  
Jenny Nasr

Micellar liquid chromatographic analysis of benzyl alcohol and benzaldehyde in injectable formulationsAn accurate, sensitive and selective reversed-phase micellar liquid chromatographic method was developed for simultaneous determination of benzyl alcohol and benzaldehyde. This method was applied in different injectable formulations containing diclofenac, piroxicam, lincomycin and clindamycin. The method showed excellent linearity in the range of 10-100 μg mL-1and 1-20 μg mL-1with the limit of detection (S/N = 3) 0.25 μg mL-1(2.3 x 10-6mol L-1) and 0.12 μg mL-1(1.13 x 10-6mol L-1) for benzyl alcohol and benzaldehyde, respectively. The suggested method was successfully applied to the analysis of the studied drugs in bulk with average recoveries of 100.1 ± 1.0% for benzyl alcohol and 100.4 ± 1.6% for benzaldehyde, and to the determination of benzyl alcohol and benzaldehyde in injectable formulations with the respective average recoveries of 99.8 ± 0.3 and 100.0 ± 0.4%.


1999 ◽  
Vol 82 (5) ◽  
pp. 1140-1145 ◽  
Author(s):  
G William Chase ◽  
Ronald R Eitenmiller ◽  
Austin R Long

Abstract A liquid chromatographic method for vitamin K1 in milk-based infant formula is described. The vitamins are extracted from infant formula by matrix solid-phase dispersion and quantitated by reversed-phase chromatography with fluorescence detection. Vitamin K1 is converted to the fluorescent hydroquinone with a postcolumn zinc reductive reactor. The limit of detection is 12 pg, and the limit of quantitation is 38 pg on-column. Linear responses were obtained in the range 0.55-22.1 ng/mL (r2 = 0.9998). Recoveries of vitamin K1 from an analyte-fortified blank material for milk-based infant formula averaged 91.7% (n = 25). The method provides a rapid, specific, and easily controlled assay for vitamin K1 in fortified infant formula.


1980 ◽  
Vol 26 (10) ◽  
pp. 1499-1503 ◽  
Author(s):  
M D Ullman ◽  
R E Pyeritz ◽  
H W Moser ◽  
D A Wenger ◽  
E H Kolodny

Abstract Quantitative high-performance liquid chromatographic analysis of perbenzoylated sphingolipids has been used to study the correlations of body chemistry to clinical phenomena. Plasma sphingolipids were isolated from 32 Gaucher (β-glucosidase deficiency) and six Fabry (α-galactosidase deficiency) patients by solvent partition and chromatographic separation on silicic acid columns. Plasma sphingolipids from a patient undergoing plasma-exchange were separated from interfering lipids with reversed-phase columns. Liquid-chromatographic analysis of sphingolipids provides useful supportive information for diagnoses because affected individuals are shown to possess increased circulating concentrations of the pathognomonic sphingolipid. We also used this technique to monitor sphingolipid concentrations in plasma and urine sediment during plasma exchange of a p atient with Fabry’s disease. Regular plasma exchanges produced and maintained decreased concentrations of sphingolipids in plasma, but near pre-exchange concentrations were observed within days after the therapy was terminated.


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