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TSRC, Tob. Sci. Res. Conf., 2013, 67, abstr. 08

Comparison of auto analyzer methods: discrete vs continuous flow.

THURSTON D.
Global Laboratory Services, Inc., Wilson, NC, USA

Chloride, Sugar, Alkaloids, and Nitrate results were compared using a discrete analyzer and a continuous flow auto analyzer. The new generation discrete analyzers are more automated than the continuous flow auto analyzers. In our initial assessment, the discrete analyzer yielded greater throughput and reliability than the continuous flow auto analyzer. We found the SmartChem 200 discrete analyzer performed comparably for methods such as chlorides and alkaloids. However, sugars and nitrates values were generally lower. For sugars, this is due to the discrete analyzer using an enzymatic method that is specific for sugars, while the continuous flow auto analyzer uses a potassium ferricyanide color reagent for determination that not only reacts with sugars, but also polyphenols and proteins. For nitrates, the discrete analyzer uses a cadmium coil reduction of nitrate to nitrite for nitrate determination, while the continuous flow auto analyzer uses a hydrazinium sulfate-copper sulfate reagent for nitrate reduction to nitrite. The exact reason for higher results from the continuous flow auto analyzer is unclear. Precision was found to be comparable on the two analyzers for chlorides and nitrates.