Table 3 Instrumental parameters for prednisone and prednisolone using the confirmation method based on negative APCI and “in source” collisional fragmentation of the deprotonated molecular ion to yield the [M-H-(HCHO)]− precursor ion
MS parameters | CUR = 20 psi | CAD = 2 psi | ||||||||
GS1 = 50 psi | T = 300 °C | |||||||||
NC = - 3 V | ihe = ON | |||||||||
SRM protocol | Target | Qualifier 1 | Qualifier 2 | |||||||
Analyte | Precursor Ion | DP (V) | Fragment | CE (V) | Fragment | (qualifier 1/quantifier %) | CE (V) | Fragment | (qualifier 2/quantifier %) | CE (V) |
Prednisolone | 329.1 | −96 | 295.4 | −25 | 280.2 | 90% | −31 | 187.1 | 81% | −25 |
Prednisone | 327.2 | −90 | 149.2 | −39 | 285.4 | 45% | −25 | 270.3 | 26% | −28 |