HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC METHODS FOR THE SPECIFIC MONITORING OF NICKEL AND VANADIUM IN MUNICIPAL AIR AT THE NANOGRAM PER CUBIC METER LEVELS

In order to develop the municipal air surveillance systems, Ni and V i n airborne particulates, which are emitted by combustion of fossil fue l, can be employed as suitable index species. The ultra-trace determin ations of these elements down to subnanograms per cubic meter of air i n airborne particulate matrices have been successfully achieved with a coupled scheme of reversed-phase liquid chromatography and a spectrop hotometric detection. The precolumn (off-line) chelation reagents, aro ylhydrazones having O,N,O and N,N,O donor sets are appropriate to V an d Ni, respectively, in terms of the specificity for these ions, which assures extraordinary suitability to the airborne particulate matrices being free from the interferences notably by Al and Fe. The detection limits (3 sigma basis) of the methods reach down to 10 pg for V and 3 0 pg for Ni in 0.1-mL injections. The monitoring data of these element s in air samples collected in Sendai City, Japan, are reported. Even i n less polluted air, V is accurately detected in the range of 1.5-3.5 ng/m(3) with a short sampling period for only 24 h (ca. 30 m(3) air). The very low detection limit of 0.3 ng of V/m(3) is demonstrated for t he continuous monitoring with such small sampling volume.