Simplified liquid-chromatographic assay of amiodarone and desethylamiodarone after solid-phase extraction.

1986 ◽  
Vol 32 (5) ◽  
pp. 890-893 ◽  
Author(s):  
P T Pollak ◽  
S G Carruthers ◽  
D J Freeman
Keyword(s):  
High Performance ◽  
Solid Phase ◽  
High Performance Liquid Chromatographic ◽  
Small Sample ◽  
Phase Method ◽  
Liquid Chromatographic Method ◽  
Solid Phase Method ◽  
Cardiovascular Medications ◽  
Liquid Chromatographic ◽  
Method Of Extraction

Abstract We describe a rapid, simplified isocratic "high-performance" liquid-chromatographic method for simultaneous measurement of the antiarrhythmic drug amiodarone and its major metabolite, desethylamiodarone, in small volumes of sera (100 microL). Compared with liquid-liquid extraction, the solid-phase method of extraction saves time and glassware and improves reproducibility for small sample volumes. Amiodarone and desethylamiodarone could be measured at concentrations as low as 250 micrograms/L. Standard curves for the drug and metabolite are linear over the range of concentrations found in our patients. Within-run CVs (n = 6) ranged from 2.7% to 4.5% for amiodarone and from 4.0% to 5.7% for desethylamiodarone over the range of 250 to 4000 micrograms/L. Between-run CVs (n = 12) were 8.3% and 5.7% for amiodarone and desethylamiodarone, respectively. Commonly used cardiovascular medications do not interfere with the assay.

Liquid-chromatographic measurement of nitrazepam in plasma.

1982 ◽  
Vol 28 (7) ◽  
pp. 1478-1481 ◽  
Author(s):  
H Kelly ◽  
A Huggett ◽  
S Dawling
Keyword(s):  
Complete Resolution ◽  
High Performance ◽  
Internal Standard ◽  
High Performance Liquid Chromatographic ◽  
Small Sample ◽  
Ultraviolet Detector ◽  
Liquid Chromatographic Method ◽  
Chromatographic Measurement ◽  
The Stability ◽  
Liquid Chromatographic

Abstract In this simple and rapid "high-performance" liquid-chromatographic method for determining nitrazepam in plasma, serum, or whole blood, the sample at pH 7.4 is extracted into diethyl ether with an internal standard (prazepam), chromatographed, and detected at 280 nm with a fixed-wavelength ultraviolet detector. A specimen, together with standards and a quality control, can be analyzed in duplicate within 90 min. The limit of sensitivity is 5 micrograms/L (nitrazepam and 7-acetamidonitrazepam) and 50 micrograms/L (7-aminonitrazepam), and no interferents have been found. This method has the advantages of a small sample requirement and complete resolution of nitrazepam and the above-mentioned major metabolites. We have used this method for analysis of therapeutic and overdose concentrations of nitrazepam, and to investigate the stability of the drug in blood.

High-performance liquid-chromatographic method compared with a modified radioimmunoassay of cotinine in plasma

1991 ◽  
Vol 37 (11) ◽  
pp. 1989-1993 ◽  
Author(s):  
S L Perkins ◽  
J F Livesey ◽  
E A Escares ◽  
J M Belcher ◽  
D K Dudley
Keyword(s):  
High Performance ◽  
Solid Phase ◽  
Plasma Concentrations ◽  
Potassium Phosphate ◽  
High Performance Liquid Chromatographic ◽  
Reversed Phase ◽  
Liquid Chromatographic Method ◽  
Assay Precision ◽  
Liquid Chromatographic ◽  
Interassay Precision

Abstract Cotinine is a sensitive and specific biochemical marker of exposure to cigarette smoke. We describe a simple solid-phase extraction of cotinine from plasma before quantification by HPLC. Extraction recovery was 97.9% +/- 11.0% for plasma concentrations of 5-400 micrograms/L. Baseline separation of cotinine and caffeine was achieved within 11 min of injection onto a C18 reversed-phase column. The mobile phase was citric acid/dibasic potassium phosphate (30 mmol/L each, pH 6.0) containing 100 mL of acetonitrile per liter. Within-day and day-to-day precision (CV) were 4.7% and 8.4%, respectively. We also describe a modification of the Nicotine Metabolite RIA kit (Diagnostic Products Corp.) for quantifying cotinine in plasma. Recovery of cotinine from supplemented plasma was within 10% of the expected value with this RIA kit. Interassay precision averaged 8.1% for samples in the range 50-400 micrograms/L; intra-assay precision averaged 3.6% at 230 micrograms/L and 8.7% at 53 micrograms/L. Correlation between the two methods was RIA = 1.13 HPLC + 14.8 (n = 128, r = 0.957, P less than 0.001). Both methods are technically simple to perform.

scholarly journals High-Performance Liquid Chromatographic Method for the Determination of Moniliformin in Corn

1998 ◽  
Vol 81 (5) ◽  
pp. 999-1004 ◽  
Author(s):  
Célestin Munimbazi ◽  
Lloyd B Bullerman
Keyword(s):  
High Performance ◽  
Chromatographic Method ◽  
Solid Phase ◽  
High Performance Liquid Chromatographic ◽  
Reversed Phase ◽  
Detector Response ◽  
Dihydrogen Phosphate ◽  
Sodium Dihydrogen Phosphate ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic

Abstract A high-performance liquid chromatographic method using UV absorption was developed for determining moniliformin in corn. The toxin was extracted with water containing 1 % tetrabutylammonium hydrogen sulfate (w/v). Paired moniliformin was partitioned into dichloromethane, which was evaporated to dryness at 50 C. The residue was dissolved in water and applied to a disposable stronganion exchange solid-phase extraction tube. Adsorbed moniliformin was eluted from the tube with 0.05M sodium dihydrogen phosphate monohydrate (pH 5). It was determined by ion-pair reversed-phase chromatography and UV measurement at 229 nm. The minimum detectable amount of pure moniliformin was 0.25 ng/injection (signal-to-noise ratio = 3:1). The detector response was linear from 0.25 to at least 20 ng. The limit of determination was 0.025 μg/g corn. Recoveries of moniliformin from corn spiked at 0.025,0.05,0.25, and 1.0 μg/g averaged 96.5,96.2, 97.2, and 97.8% respectively

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