Comparison of methods for extraction, storage, and silylation of pentafluorobenzyl derivatives of carbonyl compounds and multi-functional carbonyl compounds. Spaulding, R., S. and Charles, M., J. Analytical & Bioanalytical Chemistry, 372(7-8):808-816, 2002.
abstract   bibtex   
The employment of O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine (PFBHA) derivatization along with bis(trimethylsilyl)trifluoroacetamide (BSTFA) or N,N-(tertbutyldimethylsilyl)trifluoroacetamide (MTBSTFA) derivatization is a popular method for measurement of oxygenated organics in environmental and biological samples. Most notably, the derivatization method enables the measurement of atmospheric photooxidation products not detected by using other methods. PFBHA derivatization is often conducted in an aqueous solution. Accordingly, experiments were performed to compare the efficiency of hexane, methyl-tert-butyl ether (MTBE), and dichloromethane (CH2Cl2) for extraction of O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine (PFBHA) derivatives of carbonyl compounds from water. Further, the stability of these compounds when stored at 4degreesC in CH2Cl2 was determined, and commonly used methods for silylation of -OH and -COOH groups on the PFBHA derivatives were compared. Overall, CH2Cl2 was the most efficient solvent for extraction of PFBHA derivatives of hydroxycarbonyl compounds, dicarbonyl compounds, and keto-acids from water. Derivatives of carbonyl compounds that do not have secondary functional groups were extracted with approximately equal efficiency by each of the three solvents examined. The PFBHA derivatives of aromatic and saturated aliphatic carbonyl compounds and hydroxycarbonyl compounds were stable in CH2Cl2 at 4degreesC for greater than or equal to66 days whereas the derivatives of keto-acids and unsaturated aliphatic aldehydes begin to degrade after approximately 38 days. Comparison of four procedures for bis-(trimethylsilyl)trifluoroacetamide (BSTFA) derivatization. of -OH and -COOH groups on PFBHA derivatives revealed that primary -OH groups react efficiently in 20-100% BSTFA in CH2Cl2, and do not require a catalyst. Secondary -OH groups also react efficiently in 20-100% BSTFA, but the reaction yield improves slightly when trimethylchlorosilane (TMCS) is added as a catalyst. Reaction of tertiary -OH groups with BSTFA was very inefficient, but improved with addition of 10% TMCS to the BSTFA solution. Finally, -COOH groups seemed to react most efficiently and consistently in 100% BSTFA, without catalyst. [References: 21] 21
@article{
 title = {Comparison of methods for extraction, storage, and silylation of pentafluorobenzyl derivatives of carbonyl compounds and multi-functional carbonyl compounds},
 type = {article},
 year = {2002},
 keywords = {Spectroscopy/Instrumentation/Analytical Sciences i,Trap mass-spectrometry. Atmospheric photooxidation},
 pages = {808-816},
 volume = {372},
 id = {54d6a9bb-1ff2-35fc-b1bd-0c33b82f206f},
 created = {2015-02-12T14:35:07.000Z},
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 last_modified = {2015-02-12T20:21:10.000Z},
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 source_type = {Journal Article},
 notes = {<m:note>English Article<m:linebreak/>Current Contents(R)/Physical, Chemical &amp; Earth Sciences.<m:linebreak/>Reprint available from: Charles MJ Univ Calif Davis, Dept Environm Toxicol 1 Shields Ave Davis, CA 95616 USA Univ Calif Davis, Dept Environm Toxicol Davis, CA 95616 USA 0010 Anal. Bioanal. Chem</m:note>},
 abstract = {The employment of O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine (PFBHA) derivatization along with bis(trimethylsilyl)trifluoroacetamide (BSTFA) or N,N-(tertbutyldimethylsilyl)trifluoroacetamide (MTBSTFA) derivatization is a popular method for measurement of oxygenated organics in environmental and biological samples. Most notably, the derivatization method enables the measurement of atmospheric photooxidation products not detected by using other methods. PFBHA derivatization is often conducted in an aqueous solution. Accordingly, experiments were performed to compare the efficiency of hexane, methyl-tert-butyl ether (MTBE), and dichloromethane (CH2Cl2) for extraction of O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine (PFBHA) derivatives of carbonyl compounds from water. Further, the stability of these compounds when stored at 4degreesC in CH2Cl2 was determined, and commonly used methods for silylation of -OH and -COOH groups on the PFBHA derivatives were compared. Overall, CH2Cl2 was the most efficient solvent for extraction of PFBHA derivatives of hydroxycarbonyl compounds, dicarbonyl compounds, and keto-acids from water. Derivatives of carbonyl compounds that do not have secondary functional groups were extracted with approximately equal efficiency by each of the three solvents examined. The PFBHA derivatives of aromatic and saturated aliphatic carbonyl compounds and hydroxycarbonyl compounds were stable in CH2Cl2 at 4degreesC for greater than or equal to66 days whereas the derivatives of keto-acids and unsaturated aliphatic aldehydes begin to degrade after approximately 38 days. Comparison of four procedures for bis-(trimethylsilyl)trifluoroacetamide (BSTFA) derivatization. of -OH and -COOH groups on PFBHA derivatives revealed that primary -OH groups react efficiently in 20-100% BSTFA in CH2Cl2, and do not require a catalyst. Secondary -OH groups also react efficiently in 20-100% BSTFA, but the reaction yield improves slightly when trimethylchlorosilane (TMCS) is added as a catalyst. Reaction of tertiary -OH groups with BSTFA was very inefficient, but improved with addition of 10% TMCS to the BSTFA solution. Finally, -COOH groups seemed to react most efficiently and consistently in 100% BSTFA, without catalyst. [References: 21] 21},
 bibtype = {article},
 author = {Spaulding, R S and Charles, M J},
 journal = {Analytical & Bioanalytical Chemistry},
 number = {7-8}
}
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