title: Development of a liquid chromatographic method for picomole determination of S-sulfocysteine in trifluoroacetic acid extracts of neonatal rat brain.
abstract: Neonatal Sprague Dawley rat brain tissue was extracted with methanol, acetonitrile, acetic acid and trifluoroacetic acids (TFA). Among the extractants tested, 0.1 M TFA gave the highest recovery, 73.4 +/- 5.2% (slope of regression of 'added' vs. 'found' and standard error of the slope) of S-sulfocysteine (SSC). The poorest recovery of SSC was found with acetonitrile and 90% methanol extractions (less than 10%). Possible reasons for the low recoveries have been explored. The recovery of SSC from aqueous standards in 0.1 M TFA is 92 +/- 5%. Detection of picomole quantities of SSC has been demonstrated with a combination of the optimized extraction procedures and our previously developed detection system. Supernatant of rat brain homogenate (0.10 M TFA as extractant) was evaporated to dryness in a vacuum centrifuge. Residues were reconstituted with deionized water. Samples were separated on a reversed phase column. The mobile phase was 20 mM aqueous acetate buffer (pH 5.2) containing 0.40 mM cetyl trimethylammonium p-toluene sulfonate and 2 vol.% methanol. Electrochemical detection used dual series gold-mercury amalgam electrodes. For the first time, S-sulfocysteine was detected in normal neonatal rat brain. Its concentration is 0.99 +/- 0.25 pmol/mg brain tissue. The results indicate that TFA, rarely reported an an extractant, efficiently recovers SSC from rat brain tissues.
authors.affiliation: Department of Chemistry, Chevron Science Center, University of Pittsburgh, PA 15260, USA. sweber@pitt.edu
authors.forename: W
authors.initials: W
authors.lastname: Xia
authors.forename: M
authors.initials: M
authors.lastname: Sandberg
authors.forename: S G
authors.initials: SG
authors.lastname: Weber
mesh_terms: D000818:Animals; D000831:Animals, Newborn / Q000378:metabolism*; D001923:Brain Chemistry; D002851:Chromatography, High Pressure Liquid; D002853:Chromatography, Liquid; D003545:Cysteine / Q000031:analogs & derivatives* / Q000032:analysis; D004563:Electrochemistry; D005374:Filtration; D051381:Rats; D017207:Rats, Sprague-Dawley; D012015:Reference Standards; D012997:Solvents; D014269:Trifluoroacetic Acid; D014465:Ultrasonics
chemical_list: D012997:Solvents; C011119:S-sulphocysteine; D014269:Trifluoroacetic Acid; D003545:Cysteine