Selective Consecutive Determination of Desloratadine and Montelukast Sodium in Their Pure and Binary Dosage Form Based on Pencil Graphite Electrochemical Sensors

Table 1

The performance characteristics of the proposed described sensors.

Parameter	DES.RNK graphite sensor	MON.Cd. graphite sensor	Combined sensor
			DES	MON
Slope (mV. decade^−1)	−30.11	27.70	−29.16	29.79
Intercept	345.93	−10.17	337.60	−119.73
Linearity range (M)	5.00 × 10^−5 − 1.00 × 10^−2	1.00 × 10^−5 − 1.00 × 10^−2	1.00 × 10^−5 − 1.00 × 10^−2	5.00 × 10^−6 − 1.00 × 10^−2
Correlation coefficient	0.9996	0.9997	0.9998	0.9992
LOD^a (µM)	0.036	0.018	0.025	0.025
LOQ (µM)	0.109	0.055	0.075	0.076
Working pH range	2.5–5	6–10	2.5–5	6–10
Response time (seconds)	13	17	20	21
Lifetime (days)	63	49	49	49
Accuracy^b (R%)	100.95	99.60	98.48	101.27
Repeatability^c (RSD%)	1.53	0.31	0.98	0.44
Intermediate precision^d (RSD%)	1.90	0.86	1.05	1.19

^a.Lod 3.3 SD of intercept/slope, and LOQ = 10 ∗ SD/slope. ^bAverage of three determinations. ^cRepeatability: the intraday precision (n = 3 × 3) and average of three concentrations (5 ∗ 10⁻⁵, 5 ∗ 10⁻⁴, and 5 ∗ 10⁻³ M) were repeated three times within the day. ^dIntermediate precision: the interday precision (n = 3 × 3) and average of three concentrations (5 ∗ 10⁻⁵, 5 ∗ 10⁻⁴, and 5 ∗ 10⁻³ M) were repeated three times on two consecutive days.