A specific and simple method for the determination of arginine was dev
eloped by using a new type sensor, a surface acoustic wave (SAW)/condu
ctance sensor system. The assay was based on two coupling reactions in
volving arginase (E.C. 3.5.3.1) and urease (E.C. 3.5.1.5) with measure
ment of frequency shift that resulted from the changes of conducting i
ons produced in the reactions. Arginase,vas extracted from fresh bovin
e liver and required no further separation step. The optimum pH (8.5)
and reaction medium (Tris-HCl-EDTA, pH 8.5) were determined. We also i
nvestigated the influences of reaction medium, pH, temperature, and am
ount of urease or arginase on the frequency response of the SAW/conduc
tance sensor system. The results were linear up to 4.0 x 10(-4) M of a
rginine, and the detection limit was 2.0 x 10(-6) M. When the SAW/cond
uctance sensor system was applied to arginine analysis, the results ob
tained compared well with those of the pharmaceutical method.