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Table 1 Response characteristics and the validation data of the constructed sensors

From: New pencil graphite electrodes for potentiometric determination of fexofenadine hydrochloride and montelukast sodium in their pure, synthetic mixtures, and combined dosage form

Parameter FEX.Mol MON.Co The combined sensor
FEX MON
Slope ± SD (mV.decade−1) − 59.23 ± 0.05 28.43 ± 0.09 − 59.05 ± 0.70 28.64 ± 0.22
Intercept (mV) 435.1 − 45.6 439.2 − 44.3
Correlation coefficient 0.9991 0.9998 0.9999 0.9998
Response time (seconds) 20 27 29 32
pH range (2–4.5) (5–9.5) (2–4.5) (5–9.5)
Linearity range (mol L−1) (1.00 × 10–2–1.00 × 10–5) (1.00 × 10–2–1.00 × 10–5) (1.00 × 10–2–1.00 × 10–5) (1.00 × 10–2–1.00 × 10–5)
Life time (days) 69 45 45
Recovery a % 99.84 ± 0.51 100.92 ± 0.21 99.76 ± 0.50 100.55 ± 0.71
Repeatability b 1.59 1.18 1.70 1.63
Reproducibility c 1.73 0.29 1.91 1.99
Lodd (M) 1.4 × 10–8 2.1 × 10–8 2.5 × 10–8 1.9 × 10–8
Loq (M) 4.3 × 10–8 6.3 × 10–8 7.6 × 10–8 5.9 × 10–8
  1. aAverage of three determinations
  2. bRepeatability: the intraday precision (n = 3 × 3), average of three concentrations (5*10–5, 5*10–4 and 5*10–3 mol L−1) were repeated three times within the day
  3. cIntermediate precision: the interday precision (n = 3 × 3), average of three concentrations
  4. (5*10–5, 5*10–4 and 5*10–3 mol L−1) were repeated three times on two consecutive days
  5. dLod 3.3 SD of intercept/ slope, LOQ = 10*SD/ slope