Determination of free and total valproic acid in human plasma by capillary electrophoresis with contactless conductivity detection

Pham, Thi Thanh Thuy; See, Hong Heng; Morand, Réjane; Krähenbühl, Stephan; Hauser, Peter C (2012). Determination of free and total valproic acid in human plasma by capillary electrophoresis with contactless conductivity detection. Journal of chromatography. B - analytical technologies in the biomedical and life sciences, 907, pp. 74-78. New York, N.Y.: Elsevier 10.1016/j.jchromb.2012.08.037

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A new approach for the determination of free and total valproic acid in small samples of 140 μL human plasma based on capillary electrophoresis with contactless conductivity detection is proposed. A dispersive liquid-liquid microextraction technique was employed in order to remove biological matrices prior to instrumental analysis. The free valproic acid was determined by isolating free valproic acid from protein-bound valproic acid by ultrafiltration under centrifugation of 100 μL sample. The filtrate was acidified to turn valproic acid into its protonated neutral form and then extracted. The determination of total valproic acid was carried out by acidifying 40 μL untreated plasma to release the protein-bound valproic acid prior to extraction. A solution consisting of 10 mM histidine, 10 mM 3-(N-morpholino)propanesulfonic acid and 10 μM hexadecyltrimethylammonium bromide of pH 6.5 was used as background electrolyte for the electrophoretic separation. The method showed good linearity in the range of 0.4-300 μg/mL with a correlation coefficient of 0.9996. The limit of detection was 0.08 μg/mL, and the reproducibility of the peak area was excellent (RSD=0.7-3.5%, n=3, for the concentration range from 1 to 150 μg/mL). The results for the free and total valproic acid concentration in human plasma were found to be comparable to those obtained with a standard immunoassay. The corresponding correlation coefficients were 0.9847 for free and 0.9521 for total valproic acid.

Item Type:	Journal Article (Original Article)
Division/Institute:	04 Faculty of Medicine > Department of Dermatology, Urology, Rheumatology, Nephrology, Osteoporosis (DURN) > Clinic of Nephrology and Hypertension
UniBE Contributor:	Krähenbühl-Melcher, Stephan
ISSN:	1570-0232
Publisher:	Elsevier
Language:	English
Submitter:	Factscience Import
Date Deposited:	04 Oct 2013 14:39
Last Modified:	02 Mar 2023 23:21
Publisher DOI:	10.1016/j.jchromb.2012.08.037
PubMed ID:	22999475
Web of Science ID:	000310256500011
URI:	https://boris.unibe.ch/id/eprint/15644 (FactScience: 223054)