Fully Automated Determination of Sulfamethazine in Ovine Plasma Using Solid-Phase Extraction on Disposable Cartridges and Liquid Chromatography

in Journal of Chromatography. A (1993), 622(1), 53-60

An automatic sample preparation procedure followed by on-line injection of the sample extract into a HPLC system has been developed for the quantitative analysis of sulfamethazine and its N4-acetyl ... [more ▼]

An automatic sample preparation procedure followed by on-line injection of the sample extract into a HPLC system has been developed for the quantitative analysis of sulfamethazine and its N4-acetyl metabolite in ovine plasma. The sample clean-up was performed by solid-phase extraction (SPE) on C18 disposable extraction cartridges (DECs). All the sample handling operations were effected by a robotic auto-sampler. The DEC was first conditioned with methanol and phosphate buffer pH 7.4. After loading 1.0 ml of plasma sample onto the DEC, the latter was washed with the same buffer. The elution step was performed with methanol (0.25 ml) and the eluate was then diluted by adding 0.75 ml volume of phosphate buffer pH 6.4. A 20-microliters volume of the resultant solution was injected onto an octadecyl silica column preceded by a short guard column. The HPLC mobile phase was methanol-phosphate buffer pH 6.4 (25:75, v/v). Sulfamethazine and N4-acetylsulfamethazine were determined photometrically at 262 nm. Under these conditions, linear calibration curves ranging from 2 to 250 micrograms ml-1 have been obtained for both compounds. Drug recoveries were higher than 90% and typical relative standard deviation values were 0.7% (within-day) and 2.0% (between-day) at a plasma concentration of 50 micrograms ml-1. [less ▲]

Knowledge-based systems for method development in solid-phase extraction

Conference (1993)

Development of a knowledge-based system for the autaomated solid-phase extraction of basic drugs from plasma prior to HPLC determination

in Journal de Pharmacie de Belgique (1993), 48

Comparison of liquid-liquid extraction and liquid-solid extraction methods for the HPLC determination of verapamil and norverapamil in human plasma

in Journal de Pharmacie de Belgique (1992), 47

HPLC determination of propranolol, verapamil and norverapamil in plasma using automated liquid-solid extraction and fluorometric detection

in Journal de Pharmacie de Belgique (1992), 47

Automatic Determination of Diltiazem and Desacetyldiltiazem in Human Plasma Using Liquid-Solid Extraction on Disposable Cartridges Coupled to Hplc--Part I: Optimization of the Hplc System and Method Validation

in Journal of Pharmaceutical & Biomedical Analysis (1991), 9(10-12), 877-882

A sensitive and automated method for the analysis of diltiazem and desacetyldiltiazem in plasma has been developed using liquid-solid extraction (LSE) on disposable extraction cartridges (DECs) in ... [more ▼]

A sensitive and automated method for the analysis of diltiazem and desacetyldiltiazem in plasma has been developed using liquid-solid extraction (LSE) on disposable extraction cartridges (DECs) in combination with HPLC. After isolation from plasma, the analytes are separated on a highly deactivated octyl silica column with a mobile phase of methanol-0.05 M phosphate buffer (pH 7.4) (62:38, v/v). The analytes are monitored photometrically at 238 nm. The complete preparation of the plasma sample as well as the injection of the final extract on to the analytical column are performed automatically by means of a sample processor equipped with a robotic arm to which is attached a needle dispensing the different liquids. The internal standard solution is first added to the plasma sample. The DEC is then conditioned successively with methanol and phosphate buffer (pH 7.4). A 1.0-ml volume of sample containing the internal standard solution is applied on an extraction cartridge filled with cyanopropyl silica (50 mg). After the DEC has been washed with the same buffer, the analytes are eluted with 0.16 ml of methanol. A 0.14-ml volume of buffer is then passed through the DEC and 0.25 ml of the final extract is injected onto the HPLC column. The absolute recoveries of the drugs are about 90% and the limit of detection for diltiazem is 0.8 ng ml-1. Relative standard deviations of 2.6% (within-day) and 3.7% (between-day) have been obtained for this compound at a plasma concentration of 50 ng ml-1. [less ▲]

Automatic determination of diltiazem and desacetyldiltiazem in human plasma using liquid-solid extraction on disposable cartridges coupled to HPLC

Poster (1991)