Heptafluorobutyrate derivative

The heptafluorobutyrate derivative was selected for gas chromatographic separation, using electron capture detector (ECD), in order to enable the detection of ultramicro quantities43. The interest in the analysis of natural and synthetic hormones in very small concentrations enhanced the development of the GC method, in comparison with the UV study.44... 

Chromatography.—Considerable attention is being paid to chromatographic methods for the separation and recognition of bile acids and their derivatives. The analysis (g.l.c.) of mixtures of bile acids and their conjugates is reported to be simplified by direct conversion into heptafluorobutyrate derivatives, which occurs with simultaneous deconjugation.The carboxyl function is apparently converted into its volatile mixed cholanyl-heptafluorobutyryl anhydride. Ethyl-dimethylsilyl ethers of bile acid ethyl esters are also reported to be suitable for... 

M36, Musial, B. C., and Williams, C. N., Quantitative assay of conjugated and free bile acids as heptafluorobutyrate derivates by gas-liquid chromatography. /. Lipid Res. 20, 78-85... 

Heptafluorobutyrate derivatives are popular in isotope dilution reference methods for steroids such as testosterone [141], 17 -oestradiol [142-144] and progesterone [145-147]. Even difficult steroids such as aldosterone can be quantified in serum as the 3-enol-HFB ester by stable isotope dilution GC-MS [I4I] or after a new derivatization procedure with HFB anhydride [148). Pentafluoropropionyl derivatives have a)so found application to the quantification of oestriol [141] and urinary progesterone [149]. 

Zanetta J-P, Timmerman P, and Leroy Y (1999a) Gas-liquid chromatography of heptafluorobutyrate derivatives of the O-methyl glycosides on capillary columns a method for the quantitative determination of the monosaccharide composition of glycoproteins and glycoli-pids. Glycobiology 9 255-266. 

As for patulin, it is necessary to derivatize it with trimethylsilyl ether or heptafluorobutyrate to make it volatile. Determination of patulin through GC-MS detection and quantification of the heptafluorobutyrate derivative after treatment with hepta-fluorobutyrylimidazole has also been developed. Trimethylsiliyl can also serve as a derivatiza-tion agent for the detection of patulin through GC-ECD or GC-MS. However, it should be noted that LC methods are generally preferred over GC methods because of their easiness of application. 

Zanetta, J.P., Timmerman, P, and Leroy, Y. 1999. Determination of constituents of sulphated proteoglycans using amethanolysis procedure and gas chromatography/mass spectrometry of heptafluorobutyrate derivatives, Glycoconf J., 16 617-627. 

Isosorbide (1,4 3,6-dianhydro-D-glucitol), a metabolite of iso-sorbide dinitrate, has been determined in urine by capillary g.l.c. of its heptafluorobutyrate derivative with electron-capture... 

The heptafluorobutyrate derivatives of the three compounds showed an ion at m/e 252 in their mass spectra. Similarly, diphenylhydantoin and 5-( -hydroxyphenyl)--5 -phenylhydantoin were quantitated by single ion monitoring of the ion at m/e 165 formed in the mass spectra of their trimethylsilyl derivatives. 

Wilk and co-workers (1965) proposed a degradative procedure for analysing vanilmandelic acid (VMA) to reduce chromatographic difficulties in which VMA is cleaved by sodium periodate, and the resulting vanillin detected by electron capture as its O-trifluoroacetate derivative. Electron-capture detection can also be used in the determination of homovanillic acid as its heptafluorobutyrate derivative (Sjoquist and Anggard, 1972). 

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. 

Analyses of derivatives of NPEOs have been carried out with a large number of derivatisation reagents. Among them, polyfluorinated reagents, such as pentafluorobenzoyl chloride and heptafluorobutyric... 

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). 

Structures of four derivatives of pregnenolone employed in GC/MS in (a) the 3-heptafluorobutyrate, in (b) the 3-trimethylsilyl ether 20-pentafluorobenzyloxime, in (c) the 3-trimethylsilyl ether 20-pentaf1uorobenzylcarbox-ymethoxime, and in (d) the 20-oxime... 

Enzymatic digestion 25 with subtilisin A, ether extn, SPE cleanup, lAC cleanup, liq-liq partns, derivatization with heptafluorobutyric acid anhydride (HFB derivatives), liq-liq partns. 

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. 

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. 

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