Analytes Goodness of fit (r2) Standard error Standard error of estimate Intercept value Slope P

Bulk material

Lisinopril 0.999 10514 18750 31517 49133 0
Enalapril 0.999 4432 6217 47360 49953 0
Captopril 0.996 10515 1475 5399 60415 0
Fosinopril 0.999 7206 10108 32219 34600 0

In serum

Lisinopril 0.999 11058 18512 26548 49331 0
Enalapril 0.998 4352 6105 48474 49959 0
Captopril 0.999 7642 1020 5672 6381 0
Fosinopril 0.999 7378 10350 33125 34595 0
Table 2: Regression statistics of the proposed method.