Extraction condition ESI APCI %RE %Ion suppression %RE %Ion suppression 100 µL of 2% OPA and 100µL of Milli-Q water 43 39 53 27 100 µL of 5% OPA and 100µL of Milli-Q water 69 21 74 19 200 µL of 5% OPA and 200µL of Milli-Q water 73 17.5 76 11.23

Table 2: Effect of extraction condition of LLE on ion suppression and method efficiency.