Correction

Unfortunately, after publication of this article (Chan and Ramli 2018), it was noticed that the Results section within the abstract was incomplete. The line, “The method was sensitive to detect 0.004 mg/mL spiked drugs and was precise to quantify 0.02 mg/mL analytes” has been corrected in the original article to read, “The method was sensitive to detect at least 0.004 mg/mL spiked drugs and precise to quantify the lowest limit of analytes at 0.02 mg/mL”.