Arginine Determination with Ion-Selective Membrane Electrodes

A new method for the determination of the amino acid arginine utilizes a dual enzyme catalyzed reaction monitored with an ammonium ion selective membrane electrode of the antibiotic type. The technique gives a linear correlation between arginine concentration and electrode response over the 3 × 10−3 M to 3 × 10−5 M range and a useful, but non-linear, response over a wider range. Major interferences are urea, K+, and NH4 +, but Na+ does not interfere in the physiological concentration range.