The effects of several common interferences in human urine were
evaluated on the electrochemical determination of BPR. Table 1 summarized
the obtained results. The tolerance concentrationwas taken as the
maximum concentration of the foreign substances that caused an approximately
±5% relative error in the determination. The tolerated
ratio of the foreign substances was 200 for Na+, NH4
+, Cl−, NO3
− and
CO3 2 −; 50forK+ and I−and 25 for uric acid. As can be seen, these species
did not interfere which shows the extent of selectivity of the proposed
method for the determination of BPR.