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High-performance liquid chromatography for the quantitative determination of the urinary metabolites of toluene, xylene, and styrene (1982)

Poggi, G. ; Giusiani, M. ; Palagi, U. ; [et al.]

Springer

International archives of occupational and environmental health 50 (1982), S. 25-31

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ISSN: 1432-1246

Keywords: Toluene ; Xylene ; Styrene ; Hippuric acid ; m-Methylhippuric acid ; Phenylglyoxylic acid ; Mandelic acid ; Urinary metabolites

Source: Springer Online Journal Archives 1860-2000

Topics: Medicine

Notes: Summary A new high-pressure liquid chromatography (HPLC) method for simultaneous quantitative determination of the urinary metabolites of toluene, m-xylene, and styrene (hippuric acid, m-methylhippuric acid, phenylglyoxylic acid, mandelic acid) is described. The extraction procedure was performed on acidified urines, after addition of 4-hydroxybenzoic acid as internal standard, using a butylchloride/isopropanol mixture and drying 0.5 ml of the organic layer under nitrogen flow. The residue obtained was dissolved in 0.1 ml water/acetonitrile and 5 μl were injected into an HPLC apparatus equipped with a 0.26 × 25 cm HC ODS SIL X column. Absorbance measures were performed at 225 nm throughout the investigation. All metabolites were clearly separated in a short time (12 min) and the amounts of other urinary compounds affecting the analysis were so small that the measurement of low concentrations of the urinary metabolites could be easily performed. Linear calibration curves were obtained from 0.1 to 3 mg/ml and a correlation coefficient greater than 0.99 was found between concentrations of the standards and areas of the peaks. Statistical analysis confirms that this method, which has a high reproducibility, is simple, reliable, and useful for the biologic monitoring of industrial exposure to aromatic compounds.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00432491

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Electronic optical activity of (-)-α-phellandrene (1983)

Palmieri, P. ; Poggi, G. ; Vrbancich, J.

New York, NY [u.a.] : Wiley-Blackwell

Journal of Computational Chemistry 4 (1983), S. 260-266

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ISSN: 0192-8651

Keywords: Computational Chemistry and Molecular Modeling ; Biochemistry

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology , Computer Science

Notes: Molecular orbital computations on the sign and magnitude of the Cotton effect of (-)-α-phellandrene (a conjugated diene) and the separate twisted butadiene chromophore were performed using configuration interaction (CI) and the random phase approximation (RPA) methods with a standard minimal basis set of STO/3G orbitals. The relative contributions to the rotatory strength of (-)-α-phellandrene which arise from a twist in the diene unit, the allylic axial bond, and nonplanarity of either one or both of the C=C double bonds were determined by examining various molecular geometries. This theoretical study confirms that the allylic axial substituent/bond provides the largest contribution to the longwavelength Cotton effect. It is found that the rotatory strength arising from distortion of the planar geometry of the double bonds tends to cancel the rotatory strength arising from the sense of twist of the diene unit. The computed energies suggest that molecular geometries where the trisubstituted bond is kept planar, and where twisting is allowed about the cis double bond, may be favored over geometries where torsion is allowed about both double bonds.

Additional Material: 3 Ill.