Heptafluorobutyric acid anhydride

Shang et al. [5] used ASE for the extraction of NP and NPEO from estuarine sediments. A sample of 15-25 g was extracted three times using hexane/acetone at 100°C and 103 atm. This was followed by a clean-up step using CN-SPE. A blank sample was extracted between all samples to avoid contamination. Hexane/acetone was also used in the ASE method for alkylphenols and NPEO by Heemken et al. [12]. Extraction conditions for samples of 0.5-1 g were 100°C, 150 atm, with a static extraction step of 15 min, and a rinse step with 20 mL solvent. After a clean-up by HPLC, the analytes were derivatised with heptafluorobutyric acid anhydride for GC analysis. 

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. 

Heptafluorobutyric acid anhydride (HFAA). HFAA from Pierce Chemical Company was used. 

The extracted THC-COOH is transferred completely into Nil glass vials. As derivatization agents 50 pL pentafluoropropanol and 80 pL heptafluorobutyric acid anhydride are added and the reaction mixture is heated to 65 C for 20 min in the crimp-closed vial. The remaining derivatization reagents are then completely evaporated and the remainder is carefully transferred to conical autosampler microvials (ND 8, 1.1 mL) using a microliter syringe and toluene as solvent, so that an end volume of 200 pL is achieved for the injection of 1 pL aliquots of the derivatized extract. 

Derivatization Reagents 50 pL pentafluoropropanol 80 pL heptafluorobutyric acid anhydride... 

Glycereth-31 Glycereth-40 Heptafluorobutyric acid 1-Hexadecanethiol Hexadecenyl succinic anhydride... 

Examples of applications of derivatization reagents include diazomethane for acids and phenols acetic anhydride for phenols heptafluorobutyric acid for anilines and phenols. 

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

Reports have appeared which describe studies on interactions between perfluoroalkanecarboxylic acid anhydrides and Lewis bases as revealed by low-temperature thermographic analyses, on the preparation from hepta-fluoro-n-butyric anhydride, properties, and use in g.l.c. analysis of steroid heptafluorobutyrates and enol heptafluorobutyrates, and on the pyrolytic... 

An alternative to the use of tritiated aqueous acid or acid/organic solvent mixtures is tritiated heptafluorobutyric acid, which combines good solvating power for organic substrates, low volatility and simple preparation, from heptafluorobutyric anhydride and tritiated water, without dilution of tritium by ancillary hydrogens. The method was shown... 

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. 

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... 

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... 

The benzoylation of both activated and deactivated aromatic compounds with benzoic acids (BACs) is achieved by using bismuth triflate (10% mol) in the presence of TFAA or heptafluorobutyric anhydride (HFBA).27 meffl-Xylene undergoes acetylation with 100% yield by using acetic acid (AAC) in the presence of TFAA under bismuth or scandium triflate catalysis (10% mol). The bismuth-triflate-catalyzed reaction can be extended to different aromatics as well as to aliphatic and aromatic carboxylic acids, giving ketones in nearly quantitative yield. Benzene and chlorobenzene are benzoylated with a BAC/HFBA mixture in the presence of bismuth triflate (10% mol), giving the corresponding BPs in 90%... 

The most commonly applied methods for the analysis of polyamines in erythrocytes make use of amino acid analyzers and HPLC techniques. A capillary gas chromatographic method with nitrogen-phosphorous detection was applied to the simultaneous determination of 1,3-diaminopropane, putrescine, cadaverine (Cad), spermidine (Sd), and spermine (Sp) in human erythrocytes. Blood samples, collected by venipuncture into EDTA containing Venoject tubes, were subjected to the removal of plasma by centrifugation and erythrocytes were washed three times with two volumes of 0.9% NaCl. The stability of polyamines in erythrocyte suspensions was also investigated. Quantification of polyamines was done by comparing the peak-area ratio of each analyte and its internal standard with that of the standard. The polyamine samples were eluted with 0.1 M hydrochloric acid solutions. The eluate was evaporated to dryness at 120°C under a stream of air and 200 each of acetonitrile and heptafluorobutyric anhydride were added. The isolation of derivatives... 

A useful alternative to esterification procedure appears to be the formation of oxazolidinone derivatives using 1,3-dichlorotetrafluoroacetone, as reported recently by Husek and co-workers [246,247] the resulting heterocyclic nitrogen is further acylated with heptafluorobutyric anhydride. This procedure, which is applicable to 20 common amino acids, was found to be both rapid and sensitive [247]. 

Moore JM, Allen AC, Cooper DA (1984) Determination of manufacturing impurities in heroin by capillary gas chromatography with electron capture detection after deri-vatization with heptafluorobutyric anhydride. Anal Chem 56 642-646 Moore JM, Cooper DA, Lurie IS, Kram TC, Carr S, Harper C, Yeh J (1987) Capillary gas chromatographic-electron capture detection of coca-leaf-related impurities in illicit cocaine 2,4-diphenylcyclobutane-l,3-dicarboxylic acids, 1,4-diphenylcyclo-butane-2,3-dicarboxylic acids and their alkaloidal precursors, the truxillines. J Chromatogr 410 297-318... 

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