Xia W, Sandberg M, Weber S G
Department of Chemistry, Chevron Science Center, University of Pittsburgh, PA 15260, USA.
J Pharm Biomed Anal. 1999 Feb;19(1-2):261-8. doi: 10.1016/s0731-7085(98)00197-6.
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.
采用甲醇、乙腈、乙酸和三氟乙酸（TFA）提取新生斯普拉格-道利大鼠的脑组织。在所测试的提取剂中，0.1 M TFA对S-磺基半胱氨酸（SSC）的回收率最高，为73.4±5.2%（“添加量”与“测得量”回归曲线的斜率及斜率的标准误差）。乙腈和90%甲醇提取法对SSC的回收率最差（低于10%）。已探究了回收率低的可能原因。在0.1 M TFA中，水标准品中SSC的回收率为92±5%。通过优化的提取程序与我们之前开发的检测系统相结合，已证明可检测到皮摩尔量的SSC。大鼠脑匀浆的上清液（以0.10 M TFA作为提取剂）在真空离心机中蒸发至干。残留物用去离子水复溶。样品在反相柱上进行分离。流动相为含0.40 mM对甲苯磺酸十六烷基三甲基铵和2%（体积分数）甲醇的20 mM乙酸盐水溶液缓冲液（pH 5.2）。电化学检测使用双串联金汞齐电极。首次在正常新生大鼠脑中检测到S-磺基半胱氨酸。其浓度为0.99±0.25 pmol/mg脑组织。结果表明，TFA作为一种很少被报道的提取剂，能有效地从大鼠脑组织中回收SSC。
