Pentafluorobenzyl derivatives

Soils treated with Carbamyl and Carbofuran have been analysed by gas chromatography following conversion of N-methyl carbamates to their pentafluorobenzyl derivatives [84],... 

Chau and Terry [146] reported the formation of penta-fluorobenzyl derivatives of ten herbicidal acids including 4-chloro-2-methyl-phenoxy acetic acid [145]. They found that 5h was an optimum reaction time at room temperature with pentafluorobenzyl bromide in the presence of potassium carbonate solution. Agemian and Chau [147] studied the residue analysis of 4-chloro-2-methyl phenoxy acetic acid and 4-chloro-2-methyl phenoxy butyric acid from water samples by making the pentafluorobenzyl derivatives. Bromination [148], nitrification [149] and esterification with halogenated alcohol [145] have also been used to study the residue analysis of 4-chloro-2-methyl phenoxy acetic acid and 4-chloro-2-methyl phenoxybutyric acid. Recently pentafluorobenzyl derivatives of phenols and carboxylic acids were prepared for detection by electron capture at very low levels [150, 151]. Pentafluorobenzyl bromide has also been used for the analytical determination of organophosphorus pesticides [152],... 

Saltar and Paasivirta [155] have described a method for the analysis in soils of MCPA (4-chloro-2-methyl phenoxy acetic acid) and two of its main metabolites, 4-chloro-o-cresol and 6-chloromethyl catechol by gas chromatography of their pentafluorobenzyl derivatives (Fig. 9.12). After derivitization of the residue extract, a clean-up procedure was applied. The best recoveries of compounds from soil were obtained when the extraction was performed by shaking with ether-acetone-heptane-hexane (2 1 1 1) from acidified soil and when the clean-up was done by thin layer chromatography (Table 9.17). Detection limits were in the range 20-25ng absolute. 

Potable water and raw source water Sample acetylated in situ by addition of acetic anhydride, solvent extracted and concentrated alternatively, extracted acidic sample derivatized by pentafluorobenzyl bromide and cleaned up by column chromatography HRGC-ECD (for pentafluorobenzyl derivative) HRGC-MS (for acetyl derivative) <50 ng/L (pentafluorobenzyl) <50 ng/L (acetyl derivative) 10-64% (pentafluorobenzyl derivative) 70-132% (acetyl derivative) Sitholeetal. 1986... 

Kawahara, F. K Gas Chromatographic Analysis of Mercaptans, Phenols and Organic Acids in Surface Water with use of Pentafluorobenzyl Derivatives ... 

Fig. 2.3.2 Formation of G A A//> - a I an i n e - m ethyl r m ate and GABA// -alanine-methylfor-mate-pentafluorobenzyl derivative...

NaOH extn, pentafluorobenzyl derivative, liq-liq partns, SPE cleanup, derivatization with MSTFA (TMS derivatives)... 

Mesurol (N-methyl type carbamate) Plants, blueberries Pervaporation of trifluoroacetyl and pentafluorobenzyl derivatives GC, GC-MS [62,63]... 

Conversion to pentafluorobenzyl derivatives provides an alternative and sensitive assay for both cyanide and thiocyanate, and allows sensitive detection by ECD, or by MS using SIM at... 

At this stage we also investigated the formation of derivatives that would permit analysis by gas chromatographic techniques other than gas chromatogra-phy/mass spectrometry. We first investigated the reaction with pentafluorobenzyl bromide (PFBB). We found that PFBB is as reactive as the simple alkyl iodides (Fig. 5) consequently the pentafluorobenzyl derivatives of THC are readily prepared. 

Pentafluorobenzyl derivatives of barbiturates were chromatographed by Walle [519]. 

Mateo-Vivaracho, L., Cacho, J., and Ferreira, V. (2007). Quantitative determination of wine polyfunctional mercaptans at nanogram per liter level by gas chromatography-negative ion mass spectrometric analysis of their pentafluorobenzyl derivatives. J. Chromatogr. A., 1146, 242-250. 

G. Singh, A. Gutierrez K. Xu, A.I. Blair, IH-ECNI-MS Analysis of pentafluorobenzyl derivatives of biomolecules and drugs in the attomole range. Anal. Chem., 72 (2000) 3007. 

Lee et al. [41] developed a method for the quantitative analysis of enantiomers and regioisomers of fatty acids, hydroxy fatty acids, and related substances, including several HETEs and prostaglandins. The method is based on pre-column derivatization to pentafluorobenzyl derivatives and subsequent LC-MS analysis in an organic mobile phase using electron-capture negative-ionization (ECNI). The method is applied to lipidomic profiling, for instance of rat epithehal cells. 

Xiao, X.-Y. McCaUey, D.V. McEvoy, J. Analysis of estrogen in river water and effluents using solid-phase extraction and gas chromatography-negative chemical ionisation mass spectrometry of the pentafluorobenzyl derivatives. J. Chromatogr., A 2001, 923, 195-204. 

Figure 1. NCI-mass spectrum of the pentafluorobenzyl derivative of all trans retinoic acid.

Because of the extensive use of theophylline for the treatment of bronchial asthma and other cardiorespiratory disorders, many investigations have been carried out by means of gas chromatography to determine theophylline in serum, plasma and saliva. In many cases theophylline has been gas chromatographed as such, in some other cases after derivatization. Methyl derivatives15,16 17,18, n-butyl derivatives19,20,21,22,23,24,25,26, propyl derivatives27, pentyl derivatives and pentafluorobenzyl derivatives 3 have been made in order to obtain better gas chromatographic properties of theophylline and thus better detection possibilities. A number of stationary phases have been applied, from non-polar ones (SE-30) to very polar ones (HI-EFF 8B). OV-17 is the stationary phase that has mostly been used. 

Chalaux, N., J.M. Bayona and J. Albaiges. Determination of nonylphenols as pentafluorobenzyl derivatives by capillary gas chromatography with electron-capture and mass spectrometric detection in environmental matrices. J. Chromatogr. A 686 275-281, 1994. 

Analysis of Wine Mercaptans by Synthesis of Pentafluorobenzyl Derivatives... 

Polyfunctional thiols in wine can be determined also by synthesis of their pentafluorobenzyl derivatives (Mateo-Vivaracho et al., 2007). A volume of 6mL of wine is extracted for 15 min at low temperature (<10°C) using 1.5mL of benzene containing 4-methoxy-a-toluenethiol as an internal standard for 2-methyl-3-furanthiol (MF), 2-furfurylthiol as an internal standard for 2-furanmethanethiol (EFT), 3-MHA and... 

Figure 8.14. GC/MS analysis of amine-pentafluorobenzyl derivatives in a Cabernet Sauvignon wine. Analytical conditions 5% phenyl-95 % dimethlypolysiloxane capillary column (30 m x 0.25 mm, 0.25 pm) oven temperature program 45 °C for 4 min, 15°C/min to 280 °C, isotherm for 15 min. (1) methyl- -amine and methylamine (coeluted), (2) ethylamine, (3) n-propylaminc, (4) w-hexylamine, (5) 2-phenylethylamine, (6) 1,4-diaminobutane, and (7) 1,5-diaminopentane. (Reproduced from Journal of Agricultural and Food Chemistry, 2000, 48, p. 3314, Ngim et al., with permission of American Chemical Society.)...

Chien, C.-J., M.J. Xharles, K.G. Sexton, and H.E. Jeffries. 1998. Analysis of aribome carboxylic acids and phenols as their pentafluorobenzyl derivatives gas chromatography/ ion trap mass spectrometry with a novel chemical ionization treagent, PFBOH. Environ. Sci. Technol. 32 299-309. 

Galceran, M.T., E. Moyano, and J.M. Poza. 1995. Pentafluorobenzyl derivatives for gas chromatographic determination of hydroxy-polycyclic aromatic hydrocarbons in urban aerosols. /. Chromatogr. A 710 139-147. 

Fig. 1.20. Chromatogram of pentafluorobenzyl derivatives of some alkylbenzoic acids. Esters of acids 1 = phenylacetic 2 = phenylpropionic 3 = m-hydroxyphenylacetic 4 =p-hydrox>phenylacetic 5 = p-hydroxyphenylpropionic 6 = homovanillic. Reprinted with permission from ref. 112.

Kawahara, F.K., 1971. Gas chromatographic analysis of mercaptans, phenols and organic acids in surface waters with use of pentafluorobenzyl derivatives. Environ. Sci. Techno ., 5 235—239. 

Formation of pentafluorobenzyl derivatives using pentafluorobenzyl bromide... 

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