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Determination of polycyclic hydrocarbons in air by gas chromatography with high efficiency packed columns
233
Discussions
I cannot agree to Mr. Lucas’s categorical conclusion that “in-all practical cases the benefits of increasing chimney height will vastly outweigh the slight disadvantages which may occur at large distances from the source”. Only a detailed analysis as proposed in the paper would indicate whether there is a benefit in increasing a stack height. J. TADMOR
Soreq Nuclear Research Centre Yavne Israel
Atmospheric Environment Pergamon Press 1973. Vol. 7, p. 233. Printed in Great Britain.
DETERMINATION OF POLYCYCLIC HYDROCARBONS BY GAS CHROMATOGRAPHY WITH HIGH EFFICIENCY COLUMNS*
IN AIR PACKED
THE nomenclature should be consistent throughout and I would suggest Ring Index nomenclature. Two critical hydrocarbon carcinogens, BaP and BaA, are not separated satisfactorily, i.e. benzo(a)pyrene-benzo(e)pyrene and benz(a)anthracene-chrysene are hydrocarbon pairs usually found together. For analysis they should either be separated or the fractions should be collected and assayed photometrically. The collection of the smaller polynuclear aromatic hydrocarbons as particulate is a problem since the tricyclic hydrocarbons are mainly present in the vapor phase in the atmosphere and the tetracyclic hydrocarbons are present in the vapor phase to some extent. In addition, during the collection some of the collected hydrocarbons of this type are vaporized. Routine assay can certainly be accomplished with the procedure of Zoccolillo, Liberti and Brocco, but improvements are needed in collection, separation and analysis of these compounds and development is needed of a fast, simple and reliable procedure before a method for atmospheric (and environmental) analysis of the polynuclear aromatic hydrocarbons will become universally accepted. I think the work of Zoccolillo, Liberti and Brocco is a step in the right direction. Environmental Protection Agency National Environmental Research Center Research Triangle Park North Carolina 27711, U.S.A.
EUGENE SAWICKI
AUTHOR’S REPLY Though benzo(a)pyrene and benzo(e)pyrene are partially separated the degree of resolution in such to afford a satisfactory quantitative determination of these hydrocarbons. As far as the separation benz(a)anthracene-chrysene concerns it may be achieved by using a higher polarity stationary phase; this one however may not offer the same degree of resolution with other hydrocarbons. The determination of polycyclic hydrocarbons in air through the analysis of collected particulate matter neglects the compounds present in the vapor phase; though their concentration is very small it is considered that since the collection of particulate is carried by long term sampling, a considerable amount of these hydrocarbons will be adsorbed by the material on the filter. Further research certainly might improve the procedure for the determination of polycyclic hydrocarbons; this aim seems to be more easily reached by gas chromatography than by other analytical techniques. Istituto di Chimica Analitica Universith Rome 00185 Italy * L. ZOCCOLILLO, A. LIBER~ and D. BROCCO, Atmospheric Environment 6,715-720
ARNALJMLIBERTI
(1972).
Discussions
I cannot agree to Mr. Lucas’s categorical conclusion that “in-all practical cases the benefits of increasing chimney height will vastly outweigh the slight disadvantages which may occur at large distances from the source”. Only a detailed analysis as proposed in the paper would indicate whether there is a benefit in increasing a stack height. J. TADMOR
Soreq Nuclear Research Centre Yavne Israel
Atmospheric Environment Pergamon Press 1973. Vol. 7, p. 233. Printed in Great Britain.
DETERMINATION OF POLYCYCLIC HYDROCARBONS BY GAS CHROMATOGRAPHY WITH HIGH EFFICIENCY COLUMNS*
IN AIR PACKED
THE nomenclature should be consistent throughout and I would suggest Ring Index nomenclature. Two critical hydrocarbon carcinogens, BaP and BaA, are not separated satisfactorily, i.e. benzo(a)pyrene-benzo(e)pyrene and benz(a)anthracene-chrysene are hydrocarbon pairs usually found together. For analysis they should either be separated or the fractions should be collected and assayed photometrically. The collection of the smaller polynuclear aromatic hydrocarbons as particulate is a problem since the tricyclic hydrocarbons are mainly present in the vapor phase in the atmosphere and the tetracyclic hydrocarbons are present in the vapor phase to some extent. In addition, during the collection some of the collected hydrocarbons of this type are vaporized. Routine assay can certainly be accomplished with the procedure of Zoccolillo, Liberti and Brocco, but improvements are needed in collection, separation and analysis of these compounds and development is needed of a fast, simple and reliable procedure before a method for atmospheric (and environmental) analysis of the polynuclear aromatic hydrocarbons will become universally accepted. I think the work of Zoccolillo, Liberti and Brocco is a step in the right direction. Environmental Protection Agency National Environmental Research Center Research Triangle Park North Carolina 27711, U.S.A.
EUGENE SAWICKI
AUTHOR’S REPLY Though benzo(a)pyrene and benzo(e)pyrene are partially separated the degree of resolution in such to afford a satisfactory quantitative determination of these hydrocarbons. As far as the separation benz(a)anthracene-chrysene concerns it may be achieved by using a higher polarity stationary phase; this one however may not offer the same degree of resolution with other hydrocarbons. The determination of polycyclic hydrocarbons in air through the analysis of collected particulate matter neglects the compounds present in the vapor phase; though their concentration is very small it is considered that since the collection of particulate is carried by long term sampling, a considerable amount of these hydrocarbons will be adsorbed by the material on the filter. Further research certainly might improve the procedure for the determination of polycyclic hydrocarbons; this aim seems to be more easily reached by gas chromatography than by other analytical techniques. Istituto di Chimica Analitica Universith Rome 00185 Italy * L. ZOCCOLILLO, A. LIBER~ and D. BROCCO, Atmospheric Environment 6,715-720
ARNALJMLIBERTI
(1972).