Although granular activated carbon (GAd, fluidizedbed

Hybrid microchips containing high aspect ratio gas chromatograph (GC) columns with an integrated on-chip split injection and a flame ionization detector were developed. Two different column configurations, spiral and serpentine, both 1 m long by 50 μm wide and 500 μm tall, were fabricated out of electrodeposited nickel. The hybrid chip allowed injection plugs on the order of 1-2 ms, which lowered the height equivalent to theoretical plates (HETP) and allowed a comparison of system level band broadening between the two column configurations. The gas phase band broadening was estimated by measuring the flow characteristics and peak broadening of an unretained compound, and the results were compared with kinetic models. Experimental results show that both spiral and serpentine column layouts had similar flow and band broadening, suggesting that gas phase band broadening may be independent of column layout. The necessity for narrow injection bands for fast micro-chip chromatographic analysis was demonstrated, which emphasized the importance of component integration in designing powerful micro-analytical systems.

A collaborative study was conducted on a gas chromatographic method for determining metribuzin. Two 75% dry flow able and two 42% liquid flowable formulations were analyzed by 18 laboratories. Formulations were extracted by shaking or ultrasonic mixing for 1-5 min with methylene chloride which contained di-n-butyl phthalate as an internal standard. The extracts were injected into a gas chromatograph equipped with an OV-225 column. Peak area ratios and peak height ratios showed no significant difference. The reproducibility coefficient of variation was 0.75% for the 75% formulation and 1.41% for the 42% formulation. This GC method has been adopted official first action.