DNPH method cartridges

In another intercomparison using TDLS, several DNPH methods, the 1,3-cyclohexanedione diffusion scrubber, and the enzymatic method were compared using both spiked samples and ambient air. The TDLS was used as a standard for comparison. For ambient air measurements, results obtained with the 1,3-cyclohexanedione diffusion scrubber were about 30% higher than those obtained with TDLS, whereas results for the enzymatic method were about 35% lower. The DNPH cartridge measurements were quite variable, which may... 

Trace acetone in water may be determined by a fast HPLC method (Takami et al., 1985) aqueous sample passed through a cartridge packed with a moderately sulfonated cation-exchange resin charged with 2,4-dinitrophenylhydrazine (DNPH) DNPH derivative eluted with acetonitrile and analyzed by HPLC with a 3-mm ODS column. 

Alternatively, a measured volume of air drawn through a prepacked cartridge coated with acidified DNPH the DNPH derivative of acetone eluted with acetonitrile and measured by HPLC-UV as above (U.S. EPA Method TO-11, 1988). 

Air drawn through a cartridge containing silica gel coated with acidified DNPH derivative eluted with acetonitrile and determined using isocratic reverse phase HPLC with UV detection at 360 nm (U.S. EPA 1988, Method TOll) recommended flow rate 1 L/min sample volume 100 L. 

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