DIRECT ON-COLUMN DERIVATIZATION IN GAS-CHROMATOGRAPHY .3. ON-COLUMN BENZYLATION REAGENTS AND THE DEVELOPMENT OF -BIS(TRIFLUOROMETHYL)BENZYL-DIMETHYLPHENYLAMMONIUM FLUORIDE, AN EFFICIENT NEW ON-COLUMN DERIVATIZATION REAGENT

Direct on-column methylation using methylammonium or sulfonium salts i s well established. It has now been demonstrated that benzylammonium s alts are effective derivatisation reagents for direct on-column benzyl ations of acids and phenols. They are particularly useful for the deri vatisation of lower aliphatic acids where methyl derivatives are too v olatile for convenient GC determination and for simple phenols were re agent by-products from on-column methylation interfere with determinat ion of cresols. 5-Bis(trifluoromethyl)benzyldimethylphenylammonium flu oride is a readily prepared and highly efficient new reagent for direc t on-column derivatisation in GC and GC-MS. It produces derivatives wi th phenols which are not only easily detected by GC with electron-capt ure detection but which also give a total ion current 1.5-3-times high er than the corresponding methyl derivatives in the CC-MS of phenols a nd acids.