B.J. Corbett

Identification of the individual polychlorinated biphenyls in a mixture of gas—liquid chromatography

Retention indices were computed for all of the 210 possible chlorinated biphenyls on 13 gas chromatographic liquid phases. All possible pairwise comparisons of retention indices were made for each liquid phase, each pair of liquid phases and each set of three liquid phases. On the basis of a closeness criterion of 10 (deltaRI = RIa - RIb = 10), those combinations of three or fewer liquid phases which could distinguish between nearly all possible pairs of chlorinated biphenyls were selected. Further considerations such as column efficiencies, analysis time required, resolution achievable and availability led to the selection of several common liquid phases for the qualitative and, in some cases, quantitative analysis of the individual components of mixtures of polychlorinated biphenyls. A few specific applications are discussed.

Identification of tertiary aminomethylenedioxy-propiophenones as urinary metabolites of safrole in the rat and guinea pig

Abstract Three nitrogen-containing metabolites of safrole (1-allyl-3,4-methylenedioxy-benzene) are excreted in the urine of rats and/or guinea pigs following oral or intraperitoneal administration. The major safrole basic ninhydrin-positive metabolites of the guinea pig and rat are 3- N - N -dimethylamino-1-(3′,4′-methylenedioxyphenyl)-1-propanone and 3-piperidyl-1-(3′,4′-methylenedioxyphenyl)-1-propanone, respectively. In addition, the rat also excretes the above N , N -dimethylaminoketone and trace amounts of 3-pyrrolidinyl-1-(3′,4′-methylenedioxyphenyl)-1-propanone. All three of these aminoketones decompose to form 1-(3′,4−methylenedioxyphenyl)-3-propen-1-one.

Characterization of prostaglandins by combined gas-liquid chromatography and chemical ionization mass spectrometry

Abstract This report describes the advantages of chemical ionization mass spectrometry coupled with gas-liquid chromatography for the analysis of prostaglandins and similar biologically active metabolites. By the use of this technique, a more thorough knowledge of the chemical structure of numerous widely used derivatives of various prostaglandins is possible. As indicated in the discussion, care must be exercised in the choice of specific types of derivative for the purpose of structural identification of the intact prostaglandins and their intact metabolites.

Differentiation and characterization of isomeric polychlorinated biphenyls by gas-liquid chromatography coupled with electron impact and chemical ionization mass spectrometry.

Abstract This report describes the utilization of gas-liquid chromatography coupled with chemical ionization and electron impact mass spectrometry for the characterization and isomeric differentiation of polychlorinated biphenyls (PCBs) from numerous sources. By a comparison of model compounds with very complex mixtures, one is able to gain significant information about the o,o′-chlorine interaction of PCBs as monitored by mass spectrometry. The abudance of the specific (M − Cl)+ ion assisted greatly in the isomeric differentiation of dichloro-, hexachloro-, and heptachlorobiphenyls. Furthermore, by the indepth characterization by mass spectrometry of the Ullman reaction products formed in the preparation of 14C-labeled PCB′s, one may conclude that a very complex mixture of dichloro- and trichlorobiphenyls is formed from a specific pure isomeric iodomonochlorobenzene during the Ullman reaction. As revealed by the use of gas-liquid chromatography coupled with electron impact mass spectrometry, care must be exercised in choosing the type of organic synthetic reactions for the preparations of polychlorinated biphenyls which will be used for biological testing in order to minimize isomeric contamination.

Purification and partial characterization of nonspecific lipase from rat pancreas.

Nonspecific lipase (also referred to as micelle lipase and secondary ester hydrolase) has been purified to electrophoretic homogeneity starting from acetone powder of rat pancreas. The purified enzyme is found to have a molecular weight (gel filtration) of 64 000 +/- 2000, and an equivalent weight (titration with E-600) of 65 000. Nonspecific lipase is seen to be very sensitive to inhibition by organophosphates but resistant to quinine. Evidence for the presence of sulfhydryl and imidazole groups essential for activity is presented, and some observations on substrate specificity are made. The purified enzyme appears to lack phosphate groups and lipids, and is unstable under conditions of low ionic strength and/or exposure to 2-mercaptoethanol.

Urinary excretion of tertiary amino methoxy methylenedioxy propiophenones as metabolites of myristicin in the rat and guinea pig.

Abstract Two nitrogen-containing metabolites of myristicin (1-methoxy-2,3-methylenedioxy-5-allyl benzene) are excreted in the urine of rats and guinea pigs following oral or intraperitoneal administration. The major basic ninhydrin-positive urinary metabolite of myristicin in the rat is 3-piperidyl-1-(3′methoxy-4′,5′-methylenedioxyphenyl)-1-propanone, while the major basic ninhydrin-positive urinary metabolite of the guinea pig is 3-pyrrolidinyl-1-(3′methoxy-4′,5′-methylenedioxyphenyl)-1-propanone. In addition, the rat and guinea pig excrete trace quantities of the pyrrolidinyl ketone and piperidyl ketone, respectively. In contrast to the urinary basic metabolites of safrole, no detectable quantity of the N , N dimethylamino ketone was present in either rat or guinea pig urine after administration of myristicin; the guinea pig upon administration of safrole excreted only the substituted 3- NN -dimethyl amino propiophenone.

The metabolism of piperonyl butoxide in the rat with 14C in the methylenedioxy or α-methylene group

Abstract The metabolism of methylenedioxy- 14 C- and α-methylene- 14 C-piperonyl butoxide in the rat was elaborated using both thin-layer and radioautographic techniques. Following single intravenous injection of the methylenedioxy- 14 C isotope, 13 metabolites were detected in the bile and 11 in the urine, while the analogous administration of the α-methylene- 14 C isotope resulted in 24 metabolites in the bile and 26 in the urine. Co-chromatographic procedures have suggested the similarity (in R P values) of a total of 14 biliary and 14 urinary metabolites arising from both isotopes. In addition, significant radioactivity from each isotope was detected in the lung and fat and identified as unchanged piperonyl butoxide in both cases. The rates of biliary elimination of metabolites from both isotopes indicated initially high levels of excretion followed by a prolonged period of elimination. The significance of this in addition to the tissue residues is discussed.

Metabolism of naturally occurring propenylbenzene derivatives : I. Chromatographic separation of ninhydrin-positive materials of rat urine

Abstract Following oral or intraperitoneal administration of myristicin, safrole, isosafrole, asarone ( trans ) or β-asarone ( cis ) to male rats, basic ninhydrin-positive substances were exreted in the urine. These materials were separated and partially characterized by thin-layer chromatography. The same animals when given a control dosage of safflower oil did not exrete these ninhdrin-positive materials. There is an apparent requirement of a side chain double bond for the production of these products, with greater enhancement by the trans isomer than the cis . It is suggested that these urinary ninhydrin-positive materials are probably substituted phenylisopropylamines or amphetamines.

Metabolism of naturally occuring propenylbenzene derivatives : II. Separation and identification of tertiary aminopropiophenones by combines gas—liquid chromatography and chemical ionization mass spectrometry

Abstract A more simplified method of identification of the tertiary aminopropiophenones formed from various allylbenzene derivatives is reported. By use of combined gas—liquid chromatography and chemical ionization mass spectrometry, one is able to detect and verify the chemical structure of the tertiary aminopropiophenones of elemicin on nanogram quantities in the crude basic urine fraction. By use of this analytical method, it is concluded that upon oral administration of purified elimicin the rat excretes in uriner the 3-N,N-dimethylamino-, the 3-piperidyl-, and the 3-pyrrolidinyl-1-(3′,4′.5′-trimethoxyphenyl)-propan-1-ones. These tertiary aminopropiophenones of elemicin seem to decompose more easily than those reported for safrole and myristicin.

Chemical liability of the tertiary aminopropiophenones of eugenol as characterized by combined gas—liquid chromatography and chemical ionization mass spectrometry

Abstract The lability of various silylated and acetylated derivatives of the tertiary aminopropiophenones of eugenol was characterized by combined gas—liquid chromatography and chemical ionization mass spectrometry. Because of decomposition during derivatization and/or during analyses, the acetylated and unreduced silylated derivatives of these metabolites are very undesirable for gas chromatography. Reduction of the tertiary aminopropiophenones of eugenol followed by silylation at room temperature yields “d”-silyl ethers which can be satisfactorily characterized by gas chromatography and combined gas—liquid chromatography and chemical ionization mass spectrometry on microgram quantitites. The “d”-silyl ethers of these metabolits are easily decomposed by moisture, air and heat to yield the respective monosilylated nitrogen metabolites, which in turn decompose readily to yield the silylated allylic ketone and the secondary amines.