Table 2 Potentiometric selectivity coefficients of some interfering ions, using methylpheinadte-PVC sensors
From: New potentiometric sensors for methylphenidate detection based on host–guest interaction
Interferent, J | \(\mathop K\nolimits_{MP,B}^{Pot}\) Sensor 1 | \(\mathop K\nolimits_{MP,B}^{Pot}\) Sensor 2 | \(\mathop K\nolimits_{MP,B}^{Pot}\) Sensors 3 |
|---|---|---|---|
Na+ | 1 × 10−3 | 2 × 10−3 | 1.8 × 10−3 |
K+ | 2 × 10−2 | 2 × 10−3 | 1.7 × 10−2 |
Ca2+ | 1.9 × 10−3 | 1.7 × 10−3 | 2.0 × 10−3 |
Fe+ | 2.0 × 10−3 | 1.8 × 10−3 | 1.9 × 10−3 |
Acetate | 1.8 × 10−3 | 1.8 × 10−3 | 1.9 × 10−3 |
Phosphate | 2 × 10−3 | 1.7 × 10−3 | 1.9 × 10−3 |
Citrate | 2 × 10−3 | 1.8 × 10−3 | 2.0 × 10−3 |
benzoate | 2 × 10−3 | 1.8 × 10−3 | 2.0 × 10−3 |
Caffeine | 3.7 × 10−3 | 4.0 × 10−3 | 3.3 × 10−3 |
Glycine | 2.8 × 10−2 | 2.7 × 10−2 | 2.8 × 10−2 |
l-Cysteine | 2.7 × 10−2 | 2.8 × 10−2 | 2.7 × 10−2 |
Tryptophan | 2 × 10−3 | 2.1 × 10−3 | 2.1 × 10−3 |
Starch | 3.8 × 10−3 | 4.8 × 10−3 | 4.5 × 10−3 |
Magnesium stearate | 3.8 × 10−3 | 4.0 × 10−3 | 3.5 × 10−3 |
Lactose monohydrate | 3.9 × 10−3 | 4.7 × 10−3 | 3.5 × 10−3 |
Glucose | 3.7 × 10−2 | 4.3 × 10−2 | 3.3 × 10−2 |
Microcrystalline cellulose | 3.5 × 10−3 | 4.7 × 10−3 | 4.6 × 10−3 |