Chlorotrimethylsilane as a reagent for gas chromatographic analysis of fats and oils

Recent trends in the advanced analysis of bioactive fatty acids

“…Whereas basic catalysis is faster than acid catalysis, the former will transform free acids into their carboxylic salt and prevent their determination by GC analysis. A second acid catalysis avoids this problem but increases sample preparation time [169].…”

“…Eras et al have used chlorotrimethylsilane (CTMS) as an acid catalyst for the transesterification of some fatty esters in 1-propanol [170], and more recently they have developed a one-step method to transesterify acylglycerides and esterify FFAs at the same time using CTMS as reagent. This methodology provides some advantages compared to traditional derivatization protocols: CTMS is cheaper than, for example, BF 3 -MeOH and is likely to permit the use of different alcohols; the possibility of using 1-propanol instead of methanol ensured a major solubility of fat, which resulted in a short reaction period without a considerable increase in GC analysis time; CTMS is easier to handle than either HCl gas or concentrated H 2 SO 4 , and its solubility in organic solvents ensured one reaction phase in which the esterification of FFAs and the transesterification of acylglicerides occurred at the same time [169].…”

Old master paintings – A fruitful field of activity for analysts: Targets, methods, outlook

“…The other approach for preparation of the products of interest for gas chromatographic analysis is pyrolysis [16,57,58] (with or without simultaneous derivatization). The most often exploited volatile derivatives (obtained after wet hydrolysis) are: trimethylsilyl (sugars [6,8,54], oils [59]), N-tert-butyldimethylsilyl (amino acids [22,29], oils [11], resinous varnishes [51]), silyl or silylamine silyl esters (amino acids [6]), alkoxycarbonyl amino acid alkyl esters (amino acids [6,21,24,25,35]), alkyl esters (oils [23,25,37]) or N-trifluoroacetyl-O-propyl esters (amino acids [23]). Derivatizing agents are: chlorotrimethylsilane and hexamethyldisilazane -HMDS (yield silyl amino acids ester and trimethylsilyl sugar derivatives -the latter in pyridine medium in the presence of trifluoroacetic acid), N-trimethylsilyldiethylamine (TMSDEA), N,O-bis(trimethylsilyl)acetamide (BSA) (produce silylamine silyl esters), N-methyl-N-tert-butyldimethylsilyl-trifluoroacet-amide (MTBSTFA), and N,O-bis-trimethylsilyl-trifluoroacetamide (BSTFA) (form alkylsilyl esters), and alkyl chloroformates (form alkyl esters or alkoxycarbonyl amino acid alkyl esters or simple esters of fatty acids).…”

Application of factorial design in optimization of anion exchange resin based methylation of vegetable oil and fats

“…Previous methods for the preparation of FAMEs include alkaline catalysis (Destaillats & Angers, 2002;Ichihara, Shibahara, Yamamoto, & Nakayama, 1996), acid catalysis (Eder, 1995;Seppänen-Laakso, Laakso, & Hiltunen, 2002) and combined catalysis (Liu, 1994;Stransky & Jursik, 1996;Carrapiso & Garcia, 2000;Eras, Montañes, Ferran, & Canela, 2001). Potassium hydroxide, sodium hydroxide and sodium methoxide are the most common catalyst used in basic catalysis, whereas among acidic catalysts HCl, H 2 SO 4 and BF 3 are commonly employed.…”