C. F. Poole

Cyclic derivatives for the selective chromatographic analysis of bifunctional compounds

Abstract Only a few reagents capable of forming cyclic derivatives with bifunctional compounds have been described in the chromatographic literature. Some reagents are selective for a particular compound, whereas others such as the boronic acids are more generally applicable to a wide range of bifunctional compounds. All reagents provide a high degree of selectivity through the chemical discriminatory power of the reaction employed and some reagents have been developed which have high detector discriminatory power as well. These are of particular interest for the analysis of a few components (bifunctional compounds) in a complex matrix without the need for a tedious amount of sample clean-up. When it is necessary to isolate bifunctional compounds from complex sources, columns containing immobilized boronic acid groups have been used and advantage taken of the reversibility of the boronate complexation reaction for attachment and later removal of the desired bifunctional compound.

Substituted benzeneboronic acids for the gas chromatographic determination of bifunctional compounds with electron-capture detection

Abstract Seven aromatic boronic acids have been prepared and evaluated as selective analytical reagents for the gas chromatographic analysis of bifunctional compounds. The introduction of halogen atoms into the aromatic ring provides volatile derivatives which can be determined with an electron-capture detector at the picogram level.

New electron-capturing pentafluorophenyldialkylchlorosilanes as versatile derivatizing reagents for gas chromatography

Abstract Flophemesyl, ISP-flophemesyl, tert.-buflophemesyl and CM-flophemesyl derivatives of a wide range of organic functional groups can be prepared and have good gas chromatographic and electron-capture detector properties. The derivatives are compared in terms of volatility, hydrolytic stability, detector response and mass spectral properties. Bis(pentafluorophenyl)chloromethylmethylsilane is evaluated as a reagent for preparing derivatives of strong nucleophiles. CM-flophemesyl chloride is evaluated as a cyclizing reagent for preparing derivatives of β- and γ-hydroxyamines. The flophemesyl derivative of N-nitrosodiethanolamine is shown to be suitable for detecting this compound at trace levels.

Volatile metabolites in sera of normal and diabetic patients.

The profiles of volatile metabolites in serum samples from normal individuals and from individuals with diabetes mellitus with varying degrees of polyneuropathy have been studied. The transevaporator procedure was used to obtain sample extracts which were chromatographed on a highly efficient glass column coated with Silar 10C (106 m x 0.25 mm I.D.). Differences in profiles between normal subjects and diabetic subjects on no drug therapy were noticed. However, correlations between the severity of the neuropathy and the concentrations of certain ketones could not be established. Compounds present both in diabetic and normal sera have been identified by mass spectrometry.

The determination of steroids with and without natural electrophores by gas chromatography and electron-capture detection

The response of the electron-capture detector to organic compounds is poorly defined, and the steroids are no exception to this observation. For those steroids which are naturally electron-capturing, the structures of the electrophores will be defined. Other steroids can be made electron-capturing by the formation of appropriate derivatives. Some new or infrequently used reagents for this purpose (flophemesyl ethers,t-buflophemesyl ethers, pentafluorophenylhydrazone derivatives and halogensubstituted aromatic boronic acids) are described.

tert.-butylpentafluorophenylmethylchlorosilane as a reagent for the formation of hydrolytically stable alkylsilyl derivatives with electron-capturing properties

The synthesis of a new silylating reagent, tert.-butylpentafluorophenylmethylchlorosilane (tert.-buflophemesyl chloride) is described. The reagent forms volatile derivatives of alcohols, phenols, carboxylic acids, thiols and amines which are suitable for gas chromatography with electron-capture detection. The tert.-buflophemesyl derivatives are many-fold more stable towards hydrolysis than the flophemesyl derivatives to conditions such as partitioning between organic solvents and acid or base, thin-layer chromatography and column chromatography. The mass spectra of the derivatives show characteristics of both the flophemesyl and tert.-butyldimethylsilyl derivatives and are suitable for compound identification.

Comparison of elelctron-capturing boronic acids for the selective analysis of bifunctional compounds

Abstract The preparation and chromatographic properties of 2,6-dichlorobenzeneboronic, 2,4,6-trichlorobenzeneboronic and 3,5-di(trifluoromethyl)benzeneboronic acids are described. These reagents are compared with seven other electron-capturing boronic acids on the basis of their range of application, relative volatility, electron-capture sensitivity and derivative stability to establish some criteria for the selection of the most useful reagents. It is proposed that the four boronic acids 3,5-di(trifluoromethyl)benzeneboronic, 2,4-dichlorobenzeneboronic, 4-bromobenzeneboronic and 4-iodobutaneboronic acid are sufficient to meet the needs of most analytical problems.

Capillary column gas chromatographic profile analysis of volatile compounds in sera of normal and virus-infected patients.

Using a transevaporator sampling technique, the volatile profiles from 70 microliter of serum were obtained by capillary-column gas chromatography. The complex chromatograms were interpreted by a combination of manual and computer techniques and a two-peak ratio method devised for the classification of normal and virus-infected sera. Using the K-nearest neighbor approach 85.7% of the unknown samples were classified correctly. Some preliminary results indicate the possible use of the method for the assessment of virus susceptibility.

Determination of bifunctional compounds : VII. Ethylphosphonothioic dichloride as a selective reagent for the trace analysis of bifunctional compounds by gas chromatography with phosphorus-specific detection☆

Abstract Ethylphosphonothioic dichloride reacts selectively with bifunctional compounds containing OH, NH2 and COOH groups to form derivatives which are stable to gas chromatography. These derivatives can be determined at the low picogram level with nitrogen—phosphorus detector or with the flame photometric detector. The cyclic ethylphosphonothioic derivatives produce characteristic mass spectra with prominent molecular ions. The derivatives are suitable for identification purposes by gas chromatography—mass spectrometry and the prominent ion [M  C2H5S]+ should be useful for trace analysis by single ion monitoring.

The determination of bifunctional compounds. Part 1. Boronic acids with electron-capturing properties

Summary3,5-dichlorobenzeneboronic acid and 3-nitrobenzeneboronic acid have been evaluated as selective reagents for the derivatization of proximinal bifunctional compounds. Their gas chromatographic properties and response to the electron-capture detector are described.