Research Article
Simultaneous Determination of 15 Sulfonate Ester Impurities in Phentolamine Mesylate, Amlodipine Besylate, and Tosufloxacin Tosylate by LC-APCI-MS/MS
Table 3
LOD, LOQ, linear range, and regression equations for the 15 sulfonate analytes.
| | Analyte | LOD (ng/mL) | LOQ (ng/mL) | Linear range (ng/mL) | Regression equation with correlation coefficient (r) |
| | Methyl methanesulfonate | 10 | 15 | 15–150 | y = 1083.9x + 11041 (r = 0.9987) | | Ethyl methanesulfonate | 10 | 15 | 15–150 | y = 811.42x + 3743.2 (r = 0.9991) | | Propyl methanesulfonate | 15 | 40 | 40–200 | y = 279.07x + 4104.8 (r = 0.9958) | | Isopropyl methanesulfonate | 10 | 15 | 15–150 | y = 646.27x + 5004.1 (r = 0.9976) | | Butyl methanesulfonate | 10 | 12 | 12–150 | y = 1330.4x + 2849.7 (r = 0.9985) | | Methyl benzenesulfonate | 1 | 2 | 2–400 | y = 2067.7x − 208.46 (r = 0.9996) | | Ethyl benzenesulfonate | 1 | 2 | 2–400 | y = 1414.6x − 203.62 (r = 0.9997) | | Propyl benzenesulfonate | 2 | 5 | 5–400 | y = 865.35x + 547.21 (r = 0.9998) | | Isopropyl benzenesulfonate | 1.5 | 3 | 3–400 | y = 1367.5x + 454.06 (r = 0.9998) | | Butyl benzenesulfonate | 1 | 1.5 | 1.5–400 | y = 2849.6x − 706.01 (r = 0.9997) | | Methyl p-toluenesulfonate | 0.5 | 1.5 | 1.5–100 | y = 1719.3x + 505.87 (r = 0.9995) | | Ethyl p-toluenesulfonate | 1 | 2 | 2–100 | y = 881.38x − 234.18 (r = 0.9999) | | Propyl p-toluenesulfonate | 1 | 2 | 2–100 | y = 546.8x + 219.39 (r = 0.9995) | | Isopropyl p-toluenesulfonate | 1 | 2 | 2–100 | y = 1144x − 467.86 (r = 0.9995) | | Butyl p-toluenesulfonate | 0.5 | 1.5 | 1.5–100 | y = 1646.6x + 74.082 (r = 0.9998) |
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