Rapid determination of acetaminophen in physiological fluids by liquid chromatography using SDS mobile phase and ED detection.

Acetaminophen is determined in serum and urine samples by a rapid, sensitive, and precise chromatographic method without any pretreatment step in a C18 column using a pure micellar mobile phase of 0.02M sodium dodecyl sulfate at pH 7. Acetaminophen is eluted in less than 5 min with no interference of the protein band. The use of electrochemical and UV detection is compared. Linearities (r > 0.999), as well as intra- and interday precision, are studied in the validation of the method. Limits of detection (LOD) are also calculated to be 0.56, 0.83, and 0.74 ng/mL in micellar solution, serum, and urine using electrochemical detection. The developed micellar liquid chromatographic method is useful for the quantitation of acetaminophen in serum and urine. Recoveries in the biological matrices are in the 98-107% range and results are compared with those obtained using a reference method. Drug excretion (in urine) and serum distribution are studied in several healthy volunteers, and no interference from metabolites is found. The developed procedure can be applied in routine analyses, toxicology, and therapeutic monitoring.

Micellar liquid chromatography determination of some biogenic amines with electrochemical detection.

A simple and reliable liquid chromatographic procedure is successfully applied to the simultaneous determination of the biogenic amines, dopamine, serotonin, their metabolites (homovalinic acid (HVA) and hydroxyindoleacetic acid (HIAA)) as well as tyramine in serum samples. After an optimization procedure using a C18 column, the mobile phase selected was 0.15 M sodium dodecyl sulfate buffered at pH 3, in which the serum samples were directly injected and the analysis time for the five substances was less than 12 min. The use of electrochemical (ED) and ultraviolet (UV) detection was compared. The limits of detection of the biogenic amines studied were drastically improved using ED detection. Repeatability and intermediate precision were tested at three different concentrations and the relative standard deviations were below 1.5% for most assays. Finally, the method was successfully applied to the determination of biogenic amines in serum samples.

Determination of aromatic amines in water samples by capillary electrophoresis with electrochemical and fluorescence detection.

Two capillary electrophoresis methods have been compared for the determination of aniline derivatives in environmental water samples. With the first method the anilines were separated as cations by free zone electrophoresis at low pH, and detected by amperometry. For this, the separation capillary was connected through a palladium field decoupler to an electrochemical detection cell which had been modified to match the volume scale of the separation. Most anilines tested, except chlorinated compounds, could be detected with full sensitivity at a detection potential of +0.7 V. Detection limits with this detection scheme were on a low microg/l level. The alternative method involved the derivatization of the anilines with fluorescamine, the separation of the derivatives formed by micellar electrokinetic chromatography, and fluorescence detection. For detection a lamp-based, fibre optics instrument was used. Detection limits with fluorimetry were comparable with those obtained with amperometric detection (in the order of 1 microg/l). Still, this method was preferred since it gave a higher separation efficiency and shorter analysis times (approximately 4 min). The most important argument, however, was its higher reliability and ease-of-handling. Preliminary experiments with water samples collected in areas where pollution with anilines may be expected showed that the method is highly specific, with few interferences showing up in the electropherograms.