The characteristics of the response of the two sensors towards pioglitazone and the validation parameters^a.

Parameters		SC-SP-ISE	LC-ISE	HPLC
Analytes		PIO	PIO	PIO	ALG
Slope		59.40	57.20	864.64	1464.70
Intercept		663.80	604.80	−33.57	188.20
The correlation coefficient (R2)		0.9990	0.9990	0.9999	0.9998
The linear range (molar)		1 × 10−6 to 1 × 10−2	1 × 10−5 to 1 × 10−2	2.55 × 10−5 to 20.36 × 10−5	1.27 × 10−5 to 10.18 × 10−5
Working pH range		1–5.5	1–5.5	—	—
Response time (s)		10	15	—	—
Retention time (min)		—	—	2.824	1.179
Validation parameters
Accuracy (mean recovery ± SD)		99.27 ± 0.38	99.67 ± 0.78	100.07 ± 0.48	100.13 ± 0.95
Repeatability (RSD%)		0.66	0.73	0.75	0.55
Intermediate precision (RSD%)		0.61	0.52	0.98	0.47
LOD		2.4 × 10−7 M	1.7 × 10−6 M
Robustness*	a	—	—	100.05 ± 0.80	99.94 ± 0.32
	b			99.15 ± 0.58	100.24 ± 0.91
	c			100.87 ± 0.63	99.84 ± 0.72
	d			100.61 ± 0.78	99.08 ± 0.23

^a* is the average recoveries of three determinations of both PIO and ALG using: (a) mobile phase at pH = 2.8, instead of 3; (b) mobile phase contains 67% methanol, instead of 70%; (c) flow rate at 1.15, instead of 1.35; and (d) column temperature at 28 instead of 30 °C.