Pentafluoropropionic acid anhydride

Depending upon the chromatographic system utilized, cocaine analytes (especially polar metabolites) may require derivatization prior to GC/MS analysis. Commonly utilized derivatization reagents include N,0-bis(trimethylsilyl)trifluoroaceta-mide (BSTFA), pentafluoropropionic acid anhydride/hexafluoroisopropanol (PFPA)/(HFIP), N-methyl-N-trimethylsilyltrifluoroacetamide (MSTFA), pentafluoropropionic acid anhydride/pentafluoropropanol (PFPA)/(PFP), iV,0-bis(trimethylsi-lyDacetamide (BSA) and N-methyl-N-(tert-butyldimethylsilyl)-trifluoroacetamide (MTBSTEA). For ease of analysis and stability of the derivatives, the authors prefer BSTFA with 1% trimethylchlorosilane (TMCS). 

Pentafluoropropionyl derivative by pentafluoropropionic acid anhydride (PFPA). 

Previous derivatization of the extract is necessary to improve the stability of the compounds and the sensitivity and precision of subsequent GC-MS analysis. Silyl derivatives formed for example with MSTFA [43], halogenated alkene derivatives produced with heptafluorobutyric anhydride (HFBA) [36] or pentafluoropropionic acid [58] or anhydride (PFPA), as well as acetate derivatives formed using acetic anhydride [48] have been widely employed. 

Ring closure of 167 to thiazolo[3,2-b][l,2,4]triazoles can also be effected by acid anhydride, but the course of the reaction depends on the starting materials. Refluxing 167 with acetic or propionic anhydride (3-4 h) leads directly to 176. With pentafluoropropionic, heptafluorobutanic, and benzoic anhydride only diacetylated products 177 were produced (further details [76JHC(13)1225]). 

Amphetamines Acylation with acid anhydrides such as trifluoroacetic anhydride (TFAA), pentafluoropropionic anhydride (PFRA) or heptafluorobutyric anhydride (HFBA)... 

Compound 87 in acid-hydrolyzed urine serves as a tracer for occupational exposure to the corresponding diisocyanate. It was derivatized with pentafluoropropionic anhydride and determined by LC using TSP-MS and plasmaspray (PSP) MS (discharge-assisted TSP-MS). The [M — 2](—) ion was measured instrumental LOD 0.1 pg/pL LOD about 0.2 -ig/L urine, RSD 10% for 0.5 pg/L230. Another determination of 87 in urine is with isobutyl chloroformate231. 

Gas chromatographic separation of -agonist residues is generally complicated by the necessity of derivatization of their polar hydroxyl and amino functional groups. Silyl derivatives are preferentially prepared by treating sample extracts with N,0-bis(trimethylsilyl)trifluoroacetamide (470,471,473,475,483, 487), N-metliyl-N-(trimethylsilyl)trifluoroacetamide (482) or N-methyl-N-(tert-butyldimethylsilyl)trifluoroacetamide (473, 487). Pentafluoropropionic anhydride (481), phosgene (484), trimethylboroxine (480), methyl- and butylboronic acid (489), or a combination of N,O bis(trimethylsilyl)trifluoroacetamide with... 

Separation and quantitative determination of y-glutamyl-amino acids has been performed by reaction with a mixture of 2,2,3,3,3-pentafluoro-1-propanol and pentafluoropropionic anhydride followed by gas chromatography (379). 

Most derivatizations for gas chromatography are esterifications or etherifications. For example, analytes containing carboxyl groups are often converted into methyl [156], [161], pentafluorobenzyl [255]-[258], or triethyl esters [259]-[261], Analytes containing acidic hydroxyl groups (phenols, chlorophenols, glycol ethers) or amino groups (e.g.. aniline) can be derivatized with such per-fluorinated compounds as heptafluorobutyric anhydride, pentafluoropropionic anhydride [169], or pentafluorobenzoyl chloride [262]. 

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