Measuring Ultra-Low Nutrient Concentrations in the Mediterranean

Choosing the Right Analyzer

Prof. Krom says that his first ‘real’ job was working for the (then) Water Research Centre at Medmenham in the UK, where he was involved in the development of chemical applications for the Technicon AA-II autoanalyzers, which included going on secondment to Technicon for several months. Seal Analytical now own and manufacture the Auto Analyzer brand of Continuous Segmented Flow Analyzers, so Prof. Krom’s career has been connected with autoanalyzers for decades. For example, Prof. Krom is Professor (Emeritus) at the University of Leeds in the UK, where, again, he worked with Seals autanalyzers. An AA3 instrument was employed at Leeds in a project to investigate the nature of atmospheric acid processing of mineral dusts in supplying bioavailable phosphorus to the oceans.

The Auto Analyzer 3 (AA3) is a four channel system, measuring Phosphate with a long flow cell which has a detection limit of two nM. Ammonia is measured using a Jasco fluorometer with a similar ultra-low detection limit, and Silicate, which has a higher concentration, is measured using the manufacturer’s high resolution colorimetric technology.

Explaining the reasoning behind the purchase of a new AA3 at Haifa University, Prof. Krom stated that during a research cruise, it was necessary to analyse samples within a day to avoid changes in concentration due to preservation procedures. Typically they analyse 50-80 samples per day, so it was useful to be able to analyze large numbers of samples automatically. However, the main reasons for choosing the AA3 had been the precision, accuracy and low limits of detection that it provided.

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