The determination of TZ in pure solutions using the standard addition technique.

Pure added solution (mol L−1)	Taken (mol L−1)	Sensor 1		Sensor 2		Sensor 3
		Found (mol L−1)	% recovery	Found (mol L−1)	% recovery	Found (mol L−1)	% recovery
1 × 10−5	1 × 10−2	1.0098 × 10−5	100.98	0.9967 × 10−5	99.67	1.0053 × 10−5	100.53
5 × 10−5		4.934 × 10−5	98.68	5.032 × 10−5	100.64	4.9825 × 10−5	99.65
1 × 10−4		1.0008 × 10−4	100.08	0.9848 × 10−4	98.48	0.9808 × 10−4	98.08
5 × 10−4		5.0545 × 10−4	101.09	4.9335 × 10−4	98.67	5.0345 × 10−4	100.69
1 × 10−3		0.983 × 10−3	98.33	0.9965 × 10−3	99.65	0.9945 × 10−3	99.45
Mean ± S.D.		99.83 ± 1.279		99.42 ± 0.873		99.68 ± 1.043
% RSD		1.281		0.878		1.046