Heptafluorobutyric anhydride

Rajagopalan et al. [72] described an electron-capture gas chromatographic assay method for the determination of primaquine in blood. The method involves deriva-tization with heptafluorobutyric anhydride to form the diheptafluorobutyramide derivative after a single extraction at alkaline pH. The derivatives are quantitated by electron-capture gas chromatography. Blood levels of primaquine as low as 8 ng/mL can be measured with good precision. 

The heptafluorobutyric anhydride derivative of pseudoephedrine and electron capture detector have been used to enhance the sensitivity of the gas chromatographic method. Lin and co-workers36 and Cummins and Fourier37 extracted basefied urine or serum with benzene. Heptafluorobutyric anhydride is added to the benzene extract. The heptafluoro-ibutyric anhydride derivative extracted was chromatographed... 

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. 

The presence of hexamethylenediamine (4c) in hydrolyzed human urine is indicative of exposure to hexamethylene diisocyanate. The diamine was determined after derivatization with heptafluorobutyric anhydride followed by GC-CI-MS, using ammonia as the ionizing reagent and deuterated hexamethylenediamine as internal standard LOD 0.5 j.ig/L urine97. 

While GC has not been used extensively to analyze polyamines, a review in 2002 comprehensively covers useful methods (Teti et al., 2002) and a review in 2001 includes specific methods for various polyamines that are used to monitor cancer remission (Khuhawar and Qureshi, 2001). Using activated Permutit for cleanup and heptafluorobutyric anhydride for derivatization, sensitivities of 0.02-0.1 pmol were achieved for commonly analyzed polyamines using GC-ECD and human plasma samples (Teti et al., 2002). NPD also has utility because low detection limits are easily attained (Teti et al., 2002). PFB derivatives have shown some utility with GC-ECD (Coutts and Baker, 1982 Clements et al., 2004), and heptafluorobutryic anhydride with GC-ECD has also been used with success for analysis in human blood samples (Fujihara et al., 1983). 

The analysis of codeine, morphine, 6-monoacetylmorphine (6-MAM, a metabohte of heroin), and cocaine is important for many toxicology labs to determine illicit drug use. When analyzing opiates in urine samples, frequently the matrix chosen for drug screening, the conjugated metabolites must be hydrolyzed however, this process can break down 6-MAM (Christophersen et al., 1987). These compounds can be derivatized to increase sensitivity, and both BCD and NPD are used for these assays. Derivatizations used include reaction with N-methyl-N-trimethylsilyltrifluoroacetamide followed by GC-FID (Lin et al., 1994) or with N,0-bis(trimethylsilyl)trifluoroacetamide (Christophersen et al., 1987 Lee and Lee, 1991), PFPA (Christophersen et al., 1987), or heptafluorobutyric anhydride (HFBA) followed by GC-ECD. All these methods show good sensitivity and selectivity. 

Cheney et al. (1995) analyzed steroids by coupling an HPLC purification step with GC/MS. The steroids were initially characterized by their HPLC retention times compared with the retention times of tritium-labeled recovery standards. Next, the nemosteroids were characterized by their GC retention times. Finally, they were identified by their unique fragmentation spectra following derivatization with heptafluorobutyric anhydride or methoxyamine hydrochloride. For structmal identification, the mass spectra were compared to appropriate reference standards. This approach is highly specific, and its sensitivity is increased by the use of SIM. The detection limit for measuring allopregnanolone achieved in the 1995 study was 0.63 pmol (0.2 ng) starting from 100-300 mg of brain tissue. 

GC = gas chromatography EC = electrochemical (detector ECD = electron capture (detector HCD = Hall conductivity detector HFBA = heptafluorobutyric anhydride HPLC = high performance liquid chromatography NCI-MS = mass spectrometry in the negative chemical ionization mode NPD = nitrogen-phosphorus detector ppb = parts per billion UV = ultraviolet absorption SPE = solid phase extraction wt wt = weight weight... 

NBP, 4-(4-nitrobenzyl)pyridine TFTP, 2,3,5,6-tetrafluorothiophenol DDTC, Diethyldithiocarbamate BSTFA, bis (trimethylsilyl) trifluoroacetamide TFAA, trifluo-roacetic anhydride o-PA, o-phthalaldehyde HFBA, heptafluorobutyric anhydride. 

Air Air collected/derivatized through sodium hydroxide in ethanol neutralization derivatization with heptafluorobutyric anhydride solvent extraction GC/thermionic specific detection 10 pg/ L injected 100% (simulated sample) Skarping et al. 1988... 

TMS, trimethylsilane HFBA, heptafluorobutyric anhydride lAC, immunoaffinity chromatography TSP, thermospray PB, particle beam El, electron impact Cl, chemical ionization NICI, negative ion chemical ionization ECD, electron-capture detector PDA, photodiode array. 

UATh Brinkman, A de Kok, RB Geerdink. Determination of phenylurea herbicides via direct derivatization with heptafluorobutyric anhydride. J Chromatogr 283 113-126, 1984. 

P de Voogt, N Haak, RB Geerdink, UATh Brinkman. Determination of metoxuron and 3-chloro-4-methoxianiline via direct derivatization with heptafluorobutyric anhydride and GLC-ECD. Chemos-phere 13 1193-1200,1984. 

Bruce el aJL (35) determined oxyphenbutazone and phenylbutazone in plasma and urine by gas-liquid chromatography. While phenylbutazone was determined directly after extraction from blood plasma or urine, oxyphenbutazone was reacted with heptafluorobutyric anhydride prior to gas chromatography. Tanimura et al (36) described a gas-liquid chromatographic method for the determination of phenylbutazone and its metabolites, oxyphenbutazone and y-hydroxyphenylbuta-zone in human and rabbit following administration of phenylbutazone. A modified Herrmann s extraction method has been used and coupled with the gas-liquid chromatographic procedure without derivative formation for phenylbutazone and using trimethylsilylation for the metabolites. 

Brooks, J.B., Alley, C.C., and Liddle, J.A., Simultaneous esterification of carboxyl and hydroxyl groups with alcohols and heptafluorobutyric anhydride for analysis by gas chromatography, Anal. Chem., 46, 1930, 1974. 

An alternative approach for the analysis of blood samples from the same group of Iranian mustard gas victims has been described (50). As mustard gas alkylates amino acids in hemoglobin, adducts will be formed, which remain in the bloodstream for some time. Selective cleavage of the alkylated N-terminal valine of the a-chain of hemoglobin was carried out by using the modified Edman reagent pentafluorophenyl isothiocyanate. After derivatiza-tion of the adduct-derived pentafluorophenylthio-hydantoin with heptafluorobutyric anhydride, the... 

In these investigations, the authors subjected PAF to direct derivatization with pentafluorobenzoyl chloride (PFB) or heptafluorobutyric anhydride (HFB). Using a 16 0 PAF, the resulting reaction sequence is presented in Figure 6-3. The reaction mixture is evaporated under a stream of nitrogen, and the residue is partitioned between hexane and water. The derivatives noted above are found in the hexane layer, and the polar head group is located in water-soluble fraction. 

Weintraub, S. T., Lear, C. S., and Pinckard, R. N. (1990) Analysis of platelet-activating factor by GC-MS after direct derivatization with pentafluorobenzoyl chloride and heptafluorobutyric anhydride, J. Lipid Res. 31, 719-725. 

One difficulty with this method is that the derivatization process will not work for secondary amines such as methylamphetamine and 3,4-methylenedioxy methylamphetamine (MDMA). An alternative method for derivatization is therefore required in such cases. One such technique is the derivatization of the amphetamine samples with heptafluorobutyric anhydride (HFBA) [8]. 

The MCS collected on a Cambridge smoke pad was spiked with internal standards and subjected to simultaneous distillation and extraction by placing it in the distillation flask with 250 mL of a 12% NaCl aqueous solution, while the extract flask contained 15 mL of CH2CI2. Total transfer of the analytes (PAH, PAA and phenols) to the organic solvent was attained after 5 h boiling. The organic extract could be subjected to silylation for the phenols and amidation with heptafluorobutyric anhydride (Section III.B.l) for the aromatic amines, before end analysis by GC-MS112. 

Heptafluorobutylation Heptafluorobutyric anhydride codeine36 57, 6-0-acetyl-. . 57 morphine 52 54 6-0-acetylmorphine ... 

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