Ragnar Ryhage

Mass fragmentography. Identification of chlorpromazine and its metabolites in human blood by a new method.

Abstract Chlorpromazine and some of its metabolites have been identified in human blood with the combination of gas chromatography and mass spectrometry. A new method, mass fragmentography has been elaborated. It is based upon a continuous recording of up to three mass numbers characteristic of a single substance or a group of compounds. With this technique both a high sensitivity and a high selectivity which can be changed according to wish are achieved. Compounds are identified by their retention times and the fact that all mass numbers are represented in characteristic relative intensities. Refocusing on other characteristic fragments and/or the molecular ion confirms the identity. Through repeated refocusing “a partial mass spectrum” of a compound can be established even when the amounts present are too small for the scanning of a complete spectrum. With this method chlorpromazine, and its desmethylated and didesmethylated metabolites have been identified in plasma . The latter two metabolites were obtained also after treatment of the plasma with β-glucuronidase, as was 2-chlorophenothiazinylpropionic acid, which was found in quantities that allowed the scanning of a complete mass spectrum. In red blood cells the two desmethylated metabolites could be identified with mass fragmentography only after treatment with β-glucuronidase. The use of the method is discussed, particularly with regard to blood levels of drugs as related to therapeutic effects and side effects.

New Evidence for the presence of arsenocholine in shrimps (Pandalus borealis) by use of pyrolysis gas chromatography — atomic absorption spectrometry/mass spectrometry

Abstract An analytical method for the structure elucidation of quarternary organoarsenic compounds in trace amounts in fish and crustaceans has been developed in this laboratory. The two major organoarsenicals found in shrimps have been separated by ion-exchange chromatography and their stucture has been studied by the use of pyrolysis gas chromatography. Their degradation in the pyrolyzer unit has been studied by the use of atomic absorption spectrophotometer or mass spectrometer as detectors. A comparison of the analytical data of these substances and data from synthetic reference substances show complete agreement. The structures of reference compounds have been confirmed by use of nuclear magnetic resonance spectrometry and fast atom bombardment (FAB) mass spectrometry. It is demonstrated that both of the organoarsenic compounds in shrimps have a trimethylarsonio moiety e.g. the compounds have a quarternary structure. Furthermore, the more basic organoarsenic compound has a mass spectrometric fragmentation pattern similar to synthetic arsenocholine and acetylarsenocholine. Treatment of arsenobetaine with hot base produces trimethylarsineoxide in a high yield (96%). Arsenocholine, however, remains unchanged during this treatment. Treatment with sodium benzenethiolate does not result in chemical demethylation, which shows that this method together with gas chromatography-mass spectrometry is not feasible for confirmation of its structure.

Mass fragmentographic estimation of trimethylarsine oxide in aquatic organisms

Abstract An analytical method for quantitative and qualitative analysis of trimethylarsine oxide (TMAO) in biological material has been developed in our laboratorries. By use of mass fragmentographic technique together with synthetic deuterium labelled trimethylarsine oxide as internal standard it is possible to compensate for chemical and physical interactions. TMAO is, besides arsenobetaine and arsenocholine, an arsenic compound identified in fish. Low levels of TMAO are found in fresh fish, and elevated concentrations seem to be common in stored and frozen fish.

Identification of two neutral metabolites of stigmasterol found in human feces: Bile acids and sterols 162

Abstract Feces from human subjects given stigmasterol were found to contain 24β-ethyl-5β-cholest-22-en-3β-ol and 24β-ethyl-5β-cholest-22-en-3-one. These compounds were identified by GLC and mass spectrometric analysis

The origin of oxygen incorporated during the biosynthesis of prostaglandin E1

A clinical experiment wherein prostaglandin E1 was formed using sheep seminal vesicle homogenates is explained. The prostaglandin E1 which was produced was analyzed by mass spectrometry and gas chromatography. The results showed that of the 3 oxygen atoms incorporated during the procedure 2 appear as hydroxyl groups and 1 as a keto group. The study shows that the oxygens of the 2 hydroxyl groups used in the biosynthesis of prostaglandin E1 derive from oxygen gas. No conclusions can be drawn regarding the origin of the keto oxygen.

Mass Spectra of Bile Acids

In the last ten years mass spectrometry has grown to become one of the most valuable techniques for analysis and structure determination of bile acids. A very important reason for this development is the construction of combined gas chromatography—mass spectrometry instruments capable of dealing with complex biological mixtures at a high sensitivity level. Since the biochemist and clinical chemist are interested mainly in the analysis of biological materials, the aim of this chapter is to provide information on the use of this instrument combination, i.e., the use of a gas chromatograph as an inlet system or the use of a mass spectrometer as a gas chromatographic detector. Emphasis has been put on practical considerations and on correlations between mass spectra and structure rather than on mechanistic interpretations of the spectra. For details on the latter aspect the reader is referred to the books by Budzikiewicz, Djerassi, and Williams (1, 2).

Minor constitutents of human milk IV: Analysis of the branched chain fatty acids

Abstract After catalytic hydrogenation of the unsaturated fatty acids, the branched chain fatty acids of human milk fat were enriched 100–500-fold by urea fractionation. The fatty acid (FA) mixture obtained was qualitatively and quantitatively analysed by a combination of gas chromatograph-mass spectrometer (LKB 9000) using packed columns, thin film and S.C.O.T. capillary columns. More than 50 single and multi branched acids could be identified. From the distribution of the individual branching points, it is concluded, that two major pathways exist for the biosynthesis of these acids: either by chain elongation of the branched CoA-esters (such as isobutyryl-CoA, α- and β-methylbutyryl-CoA) or by methylation of the double bond of monoenoic acids. The quantitative distribution of the branched acids strongly resembles that found in many micro-organisms. Hence it is assumed, that a large number of these acids is produced in - or absorbed from - the intestinal tract.

Identification of fatty acids from butterfat using a combined gas chromatograph-mass spectrometer.

The identification and approximate quantitative determination of methyl esters of fatty acids from commercial butterfat was obtained with a combined gaschromatograph-mass spectrometer instrument. Fifty-two components, straight chain saturated and unsaturated, as well as branched chain compounds, were identified. Seven monomethyl saturated fatty acid methyl ester isomers were identified for both C 15 and C 17 , i.e. with chain lengths of 14 and 16 carbon atoms, respectively. Multibranched fatty acids with molecular weights of 326 and 368 were found. The results were obtained in one day.

Identification of methaqualone metabolites from urine extract by gas chromatography-mass spectrometry.

Abstract A rapid and sensitive method for identifying methaqualone metabolites bv means of gas chromatography-mass Spectrometry is presented. The mass spectra of TMS derivatives of ten synthetic metabolites of methaqualone have been studied and compared with the components of three silylated human urine extract. Four to five metabolites were identified in each extract.

Mass spectrometry of biosynthetically labeled ricinine

Abstract The high sensitivity and precision made possible by modern instrumentation enables mass spectrometry to be used effectively even at the low isotopic enrichment levels readily attainable in studies of biosynthesis. A particular virtue of mass spectrometry for studies of reaction paths in biosynthesis, as elsewhere, is the ability to locate a label within a molecule without prior wet-chemical degradation. However, the extraction of such information is contingent on prior knowledge of ionization-dissociation mechanisms induced by electron impact. Preparation of the specifically labeled compounds needed to define these mechanisms may be greatly simplified by employing biosynthesis if the pertinent biosynthetic pathways are well enough established. Thus, findings from studies of ricinine from labeled nicotinamide, formate, and acetate furnished the necessary basis for mass-spectral interpretation to permit use of label-retention measurements on an appropriate fragment ion to determine the position in the ricinine molecule of nitrogen administered as formamide- 15 N. Ricinine isolated 12 hr after injection of the formamide contained the label only in the ring. After 24 hr, the label was found in both the ring and the nitrile group in proportions of about 3:1.