Standard preparation
A standard stock solution containing a mixture of
saccharin, phenacetin, paracetamol, and methaqualone
having a concentration of 2 mg/mL of each of these
substances was prepared in the mobile phase. The stock solution
was further diluted with mobile phase to give the five
different concentrations (containing saccharin, paracetamol,
phenacetin and methaqualone in the range of 0.2 μg/10 μL
to 1.8 μg/10 μL, 0.4 μg/10 μL to 2 μg/10 μL, 0.4 μg/10 μL
to 2 μg/10 μL and 0.2 μg/10 μL to 1 μg/10 μL, respectively).
Five replicates of each of these five solutions were injected
for plotting the calibration curve.
For limit of detection and limit of quantification a
standard solution containing each of saccharin, phenacetin,
paracetamol and methaqualone (1 mg/mL each)
was diluted to give the different concentrations (0.05 μg/
10 μL to 2 μg/10 μL). Recovery studies were carried out
by standard addition method where three different concentrations
of above said components were prepared with
in the calibration range of corresponding components.