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The trimethylsilylated O -methyloximes of three naturally occurring 2-acetamido-2-deoxyaldoses were prepared. The mass spectra of these derivatives were recorded, and the conditions for resolving them by gas-liquid chromatography defined.

The characterization by gas-liquid chromatography-mass spectrometry of benzene-, butane-, and methane-boronate trimethylsilyl ether derivatives of some common carbohydrates has been investigated by a combination of high- and low-resolution mass spectrometry. Preparation of stereospecific derivatives with alkane- or arene-boronic acids, followed by silylation and mass spectrometry, allows the identification of isomeric structures of pentoses, hexoses, 6-deoxyhexoses, and 2-acetamido-2-deoxyhexoses.

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.

The coupling of the techniques of gas chromatography and mass spectrometry has provided the chemist with one of his most powerful analytical methods. The analysis of such diverse substances as fuels, air pollutants, food flavors, smokes, protein hydrolyzates, pesticides, lipid extracts, etc. may all require the separation and identification of the components of extremely complex mixtures.

The direct combination of gas-liquid chromatography with mass spectrometry represents one of the most powerful techniques available for the analysis of complex mixtures of lipids. Principal advantages are the extremely small amounts of material required, the relative speed of analysis, and the wealth of molecular structural information available. The ability to record rapidly several mass spectra of one emerging chromatographic peak may also frequently be of use in detecting impurities, unresolved mixtures, or thermal decomposition of the sample. In the development of new gas chromatographic analytical procedures, the combination instrument may frequently prove highly useful for following chemical reactions in the preparation of new types of derivatives for GLC.

The constituents present in hops which are retherefore been investigated as an alternative sponsible for the characteristic bitter flavor of method for performing rapid analyses. The techbeer consist of a complex mixture of closely relatnique shows considerable potential for separation ed compounds. Separation and analysis of these and detection of bittering constituents in both compounds by countercurrent distribution, the hops and beer. Hplc has also been used to follow best technique available, is slow and tedious. the rearrangement of hop components and to High-pressure liquid chromatography (hplc) has monitor synthetic reactions.

A mixture of the geometrical isomers of 2-methyl-1-thiadecalin has been separated by a combination of adsorption column chromatography and preparative gas-liquid chromatography. The configuration of each isomer has been established by mass spectrometry and PMR spectrometry with the application of the Auwers-Skita rule.

INTRODUCTION Preliminary studies on the use of mass spectrometry for the determination of amino acid sequences in peptides have been published by Biemann a al.1' 2 who reduced the peptide bonds and the terminal carboxyl by LiA1H4 or LiA1D4 to obtain polyamino-alcohols or the corresponding polyamines. For the purpose of obtaining sufficiently volatile derivatives, all later authors have used N-acyl derivatives of oligopeptide methyl (or ethyl, or t-butyl) esters. Thus, Stenhagen3 and Weygand et al.4 have obtained mass spectra of N-trifluoroacetyl methyl esters of oligopeptides up to pentapeptides and Manusadzhyan et al.5 have used N-acetyl oligopeptide ethyl esters. With a direct inlet system, Heyns and Grutzmacher6'7 have studied N-acetyl peptides and have obtained a fairly satisfactory sequential splitting, the highest peptide measured being a pentapeptide derivative of mass 539. Detailed studies of the fragmentation of peptides and their derivatives have been performed by Weygand et al.8, and Shemyakin et al.'°, the latter having especially studied depsipeptides and cyclic peptides'1' ha, The usefulness of mass spectrometry for the determination of the sequence of amino acid residues was clearly recognized in 1984, due to structural studies on natural peptidolipids12. Since then mass spectrometry has become a very helpful tool for correcting12' 13, or confirming'4 the structure of oligopeptide derivatives established by classical analytical methods; the most interesting application of mass spectrometry in this field is, however, the determination of the sequence of amino acids in oligopeptides and their derivatives. The minute quantities (10—100 g) needed for obtaining a mass spectrum and the rapidity of the measurements as well as the possibilities of automation compete favourably with other well established methods. We shall not go into details of fragmentation mechanisms, our principal aim being to try to show how the "normal" splitting of the peptide bond can be used for sequence determination. For recent reviews see references 15—19.

Steranes and triterpanes identification from Green River shale by capillary gas liquid chromatography and mass spectrometry

Gas-chromatographic columns suitable for deuteriation of steroids have been developed and applied to the characterisation of saturated and unsaturated mono-oxo-steroids by combined gas chromatography–mass spectrometry.

Monitoring of solutes eluted from a liquid chromatograph is possible by continuous introduction of the effluent solution into the ion source of a chemical ionization mass spectrometer. Detection sensitivities in the nanogram range are possible for a wide variety of solutes and solvents. Auxiliary techniques which have proved valuable for g.c.-m.s. also appear to be applicable to l.c.m.s.

The combination of thin-layer chromatography with high-resolution mass spectrometry results in a highly sensitive rapid method of analysis for polycyclic aromatic hydrocarbons. Use of a micro centrifuge technique facilitates transfer of the eluted samples from the chromatogram to the mass spectrometer and enables limits of detection in the picogram region to be obtained. In conjunction with such other techniques as paper and thin-layer chromatography, the integrated ion-current method offers great potential as an analytical technique.

THE occurrence of the “pink spot” in the urine of schizophrenics was first reported by Friedhoff and van Winkle1, who tentatively identified the substance as 3,4-dimethoxyphenethylamine (3,4-DMPEA). Subsequent interest in this amine is linked to the possibility that its formation may result from an aberration in the metabolism of the endogenous amine, dopamine, as either a resultant or aetiological factor in mental disorders2. Reports of both confirmatory3–7 and conflicting8–14 nature have appeared with respect to the identity and origin of the “pink spot”15,16. The methods which have been used to isolate and identify the “pink spot”, solvent extraction, ion-exchange chromatography, paper and thin-layer chromatography, counter-current distribution and various colour reactions, have not provided unequivocal identification. Much of the controversy originates from the non-specificity of chromatographic separation and the complexity of amines present in human urine. Indeed, several “pink spot” occur in urine extracts which are isographic in one or more of the solvent systems used to isolate the “pink spot”.

Trimethylsilyl derivatives of phosphorylethanolamine and phosphonoethylamine have been separated by gas-liquid chromatography and subsequently analyzed by mass spectrometry. The results indicate that this method is superior to earlier methods for the identification of natural phosphoric and phosphonic acid derivatives.