increased up to 8 mL in 5% (v/v) Triton X-100 and decreased slightly
above that volume. Further increasing the volume of Triton X-100 (5%)
would increase the amount of the surfactant-rich phase volume and
thus decreasing the phase volume ratio. Thus, 8 mL of Triton X-100 5%
(v/v) was used in the subsequent experiments in order to achieve the
optimal analytical signal in conjunction with the highest possible
extraction efficiency