Heptafluorobutyric acid

Histones (from S4A mouse lymphoma). Purification used a macroprocess column, heptafluorobutyric acid as solubilising and ion-pairing agent and an acetonitrile gradient. [McCroskey et al. Anal Biochem 163 427 1987.]... 

Inertsil ODS2 0.04% (v/v) heptafluorobutyric acid, 10 mM oxalic acid and 10 pM EDTA ammonium salt B ACN-HjO (90 10) containing 0.04% (v/v) heptafluorobutyric acid, 10 mM oxalic acid and 10 pM EDTA ammonium salt ... 

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. 

Ion-pair reverse phase HPLC. Aqueous samples confaining pyridoxine as infernal standard and 0.5% heptafluorobutyric acid as ion-pairing agent (IP) were injected in an RP-HPLC system with a Varian ODS-80TM column and eluted with 0.15% heptafluorobutyric acid in 24% methanol. Pyridinoline cross-link fluorescence was defecfed af Xgx 295 nm and Xem 400 nm (Bank ef al., 1997). 

The quaternary ammonium compounds paraquat and diquat are widely used non-selective contact herbicides, which are extremely toxic to humans. Fee et al. [112] established an HPLC-MS-MS procedure for the determination of these herbicides in whole blood and urine using ethyl paraquat as internal standard. After extraction with Sep-Pak C18 cartridges, analytes were separated using ion pair chromatography with heptafluorobutyric acid in 20 mM ammonium acetate and acetonitrile gradient elution. Detection was carried out in ESI MS-MS SRM mode. Using similar separation and detection conditions, paraquat, diquat, difenzoquat, and a number of structurally related quaternary nitrogen muscle relaxants (see Section 20.2.1.3) were determined in whole blood by Ariffin and Anderson [113]. 

Reagent 3 anhydrous n-heptafluorobutyric acid Solvent 1 benzene... 

HPLC mobile phase A Make 1 ml n-heptafluorobutyric acid (Pierce, 25003) up to 1000 ml with demineralised water. 

Nortestosterone, Bovine muscle Heptafluorobutyric acid GC-NICI-MS 66... 

Increased retention of the analytes can also be achieved by addition of various ion-pair reagents in the mobile phase Tetrabutylammonium cations have typically been used as counter ions, at around pH 6.5, to increase retention and improve the selectivity in the analysis of monobasic penicillins (105, 123). Alkyl-sulfonic acids have been also used to improve the separation of -lactams bearing an amine function in their side chain or having a neutral side chain. Heptanesul-fonic acid (80, 103), decanesulfonic acid (87, 93, 106), dodecanesulfonic acid (77, 107-110), or mixtures of octanesulfonic and dodecanesulfonic acids (73, 75, 78, 79) constitute the principal alkylsulfonic acids used in -lactam analysis. In some applications, heptafluorobutyric acid (74, 76) or sodium thiosulfate (90, 112, 115, 116, 121, 122) has also been used as an ion-pairing reagent. 

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. 

HFAA, heptafluorobutyric acid anyhydride BSTFA, N,O-bis(trimethylsilyl)tnfluoroacetamide 3 -hydroxysteroid dehydrogenase BSA, N,O-bis(trimethylsilyl)acetamide MSTFA, N-methyl-N-(trimethylsily)trifluoroacetamide TMS, trimethylsilane SEA, supercritical-fluid extraction PFBCMO, pentafluorobenzylcarboxymethoxime. 

NBD-CI, 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole MSTFA, N-methyl-N-(trimethylsilyl)trifluoroacetamide BSA, N, O-bis(trimethylsily-l)acetamide MTBSTFA, N-methyl-N-(tetr.-butyldimethylsily)trifluoroacetamide BSTFA, N,0-bis(trimethylsilyl)trifluoroacetamide HFB, heptafluorobutyric acid SFE, supercritical-fluid extraction. 

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