Showing papers on "Derivatization published in 1973"
TL;DR: With this technique 400 pg of PGF 2α can be determined with a precision of ±3.7% (SD), the recoveries from plasma samples, containing 1–2.5 ng/ml of any of the compounds, is about 100±10%.
107 citations
TL;DR: The benzoylation of cerebrosides with benzoyl chloride and with benzoic anhydride is described, and the derivatives that contained hydroxy and nonhydroxy fatty acids were isolated by high pressure liquid chromatography (HPLC).
57 citations
TL;DR: A technique for benzyl derivatization of fatty acids which results in enhanced ultraviolet absorption with a concomittant increase in sensitivity in liquid chromatographic (LC) separations has been developed.
Abstract: A technique for benzyl derivatization of fatty acids which results in enhanced ultraviolet absorption with a concomittant increase in sensitivity in liquid chromatographic (LC) separations has been developed. Benzylation prior to liquid chromatographic separation also provides a uniform enhancement of response for fatty acids which permits direct relative quantization without acquisition of additional calibration data. After removal of excess solvent from eluted compounds mass spectra were determined using a direct probe which confirmed the benzyl ester structures. A discussion of spectral data and the advantages of using mass spectrometry as an ancillary tool to liquid chromatography is also discussed.
55 citations
TL;DR: Epoxide hydrase has been measured in rat tissue with 3-methylcholanthrene-11,12-oxide as substrate and diol formation was assayed by gas chromatographic separation of the trimethylsilylated derivative of trans-11-12-dlhydro-11,- 12-dihydroxy-3- methylcholthrene.
Abstract: Epoxide hydrase has been measured in rat tissue with 3-methylcholanthrene-11,12-oxide as substrate; diol formation was assayed by gas chromatographic separation of the trimethylsilylated derivative of trans-11,12-dlhydro-11,- 12-dihydroxy-3-methylcholanthrene from the corresponding derivative of the 11 (or 12)-hydroxy-3-methylcholanthrene on 3 percent OV-17, which is formed from the 11,12-oxide during the derivatization. The polycyclic hydrocarbons were extracted initially from the incubation mixture with ethyl acetate. The assay is simple, inexpensive, and sensitive.
46 citations
26 citations
TL;DR: Chlorophenols have been evaluated semiquantitatively on thin-layer chromatographic (TLC) plates by using different spray reagents by means of derivatization of free hydroxyl groups and in situ fluorescence measurements.
25 citations
TL;DR: GLC methods for thedetermination of plasma pentazocine and for the determination of urinary pentazoine and its known metabolites are described and the sensitivity and reliability of the techniques are compared to other methods in the literature.
15 citations
TL;DR: In this paper, the gas chromatographic determination of iodine was extended to the ng/ml range by derivatization of iodide with 2-butanone, 2-pentanone or 3-pentane.
Abstract: Derivatization of iodine with 2-butanone, 2-pentanone, or 3-pentanone yield products which have greater response to electron capture detection and which are extracted more completely than the product of the iodine reaction with propanone. Both these observations support the extention of the gas chromatographic determination of iodine into the ng/ml range.
14 citations
TL;DR: The trimethylsilyloxy derivatives of the 11,12-epoxy, and the cis-and trans-11, 12-dihydro-11-12- dihydroxy-3-methylcholanthrene can be separated by gas chromatography on an OV-17 phase by finding the trans compound formed the expected disilylated derivative.
9 citations
TL;DR: In this article, an on-column conversion of a trimethylsilylated carbamate to the corresponding isocyanate has been studied with respect to rate of trimethyl-silylation and column temperature.
7 citations
TL;DR: In this paper, a specific, rapid and sensitive method for the quantitation of β-aminoisobutyric acid in urine is described, based on the analysis by quadrupole mass fragmentography of its N-TFA-O-n-butyl derivative using α-amino octanoic acid as an internal standard.
TL;DR: The analysis of the laxatives, sennosides A, B and C, is carried out after separation by thin-layer chromatography with simple, sensitive and rapid technique, and should be applicable to other anthraquinone compounds.
TL;DR: In this article, the separation of asymmetric amines by derivatization to the corresponding amides with N-trifluoroacetyl-L-prolyl chloride was carried out by gas-liquid chromatography, and the structure-separation relationship was studied.
Abstract: Separation of asymmetric amines by derivatization to the corresponding amides with N-trifluoroacetyl-L-prolyl chloride was carried out by gas-liquid chromatography, and the structure-separation relationship was studied. For a series of ring-substituted 1-phenyl or naphthylalkylamines, diastereoisomeric amides were better resolved on a relatively polar column than on a nonpolar column with the L(+) forms eluted before the L(−) forms and the separation was poorer as the alkyl group attached to the asymmetric carbon atom was varied from isopropyl to methyl to n-propyl to isobutyl. On the contrary, for another series of ring-substituted 1,2-diphenylethylamines, the isomeric amides were better resolved on a nonpolar column than on a polar column, the L(+) forms being eluted with longer retention than the L(−) forms, and the separation was better when the alkyl group substituted for a hydrogen of the phenyl group at α-position was bulkier. Furthermore, the optical purity of asymmetric amines was determined by m...
TL;DR: Application of the method for the analysis of colistin sulfate in the urine involved purification procedures consisting of the removal of urea, extraction of amino acids with HCl-isopropanol and passage through an ion exchange resin.
Abstract: A chemical method for the assay of colistin was developed. The method was based on the determination of the D-leucine content of colistin by gas chromatography. The procedure involved acid hydrolysis of colistin, derivatization to form the isopropyl ester of N-trifluoroacetyl-D-amino acid and analysis with a gas chromatograph using a capillary column coated with N-TFA-L-va-lyl-L-valine cyclohexyl ester. Application of the method for the analysis of colistin sulfate in the urine involved purification procedures consisting of the removal of urea, extraction of amino acids with HCl-isopropanol and passage through an ion exchange resin.