HPLC-based method using sample pre-column clean-up for the determination of methanethiol and ethanethiol in parenteral amino acid solutions.
A method has been developed for the chromatographic determination of methanethiol (MT) and ethanethiol (ET) as contaminants in amino acid parenteral nutrition (PN) solutions. The clean-up of the samples before chromatographic analysis was investigated by solid-phase extraction (SPE) on pre-columns filled with polyethylene powder (PE), aluminium oxide (AlOx), silica (SiOx), or polyurethane foam (PUF) as adsorbents. The thiols were more efficiently separated from the matrices by SPE on PUF pre-columns. Simultaneous derivatization and elution with DTNB (5,5'-dithiobis(2-nitrobenzoic acid)) enabled further discrimination between MT and ET by reversed-phase HPLC with spectrophotometric detection. The retention times for the derivatized MT and ET species were 12.5 and 23.0 min, respectively. Recoveries from spiked PN samples were calculated to be approximately 90%, and the MT and ET content of commercial PN solutions was determined using the methodology described. Detection limits of 15 and 10 microg L(-1) were calculated for MT and ET, respectively.
do Nascimento
P C
PC
Department of Chemistry, Federal University of Santa Maria, Brazil. npaulo@quimica.ufsm.br
Bohrer
D
D
Rohlfes
A L
AL
de Carvalho
L M
LM
Ramirez
A
A
D000537:Aluminum Oxide / Q000737:chemistry; D000596:Amino Acids / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D004228:Dithionitrobenzoic Acid / Q000737:chemistry; D010087:Oxides / Q000737:chemistry; D010288:Parenteral Nutrition / Q000592:standards*; D020959:Polyethylene / Q000737:chemistry; D011140:Polyurethanes / Q000737:chemistry; D017655:Silicon Compounds / Q000737:chemistry; D013438:Sulfhydryl Compounds / Q000032:analysis*
D000596:Amino Acids; D010087:Oxides; D011140:Polyurethanes; D017655:Silicon Compounds; D013438:Sulfhydryl Compounds; C116473:silicon monoxide; C005231:methylmercaptan; D020959:Polyethylene; D004228:Dithionitrobenzoic Acid; D000537:Aluminum Oxide; C007638:ethanethiol