3. Results and discussion
3.1. SDME procedure optimization
The optimized parameters of the SDME/GC–MS were: extraction
time—30 min, solvent—toluene, drop volume—1 μL, stirring speed—
300 rpm [7]. Additionally, multivariate optimization was performed
by a 22 full factorial design to identify the influence of salt addition (%
NaCl) and pH on the SDME procedure. Two replicates were performed
at the central point to estimate the experimental error [38,39], which
were minimal in the six experiments. The dependent variable
(response) was the sum of the analyte peak areas in each experiment.
Table 1 shows the studied parameters and their sampling levels.
From the planning matrix built from the Pareto chart, shown in
Fig. 2, it appears that the pH and salt effects are not significant at the
95% confidence level. Therefore, the pH was set at 5.0 (pH of the
water) and no salt was added in the following steps (Section 2.3).
3. Results and discussion3.1. SDME procedure optimizationThe optimized parameters of the SDME/GC–MS were: extractiontime—30 min, solvent—toluene, drop volume—1 μL, stirring speed—300 rpm [7]. Additionally, multivariate optimization was performedby a 22 full factorial design to identify the influence of salt addition (%NaCl) and pH on the SDME procedure. Two replicates were performedat the central point to estimate the experimental error [38,39], whichwere minimal in the six experiments. The dependent variable(response) was the sum of the analyte peak areas in each experiment.Table 1 shows the studied parameters and their sampling levels.From the planning matrix built from the Pareto chart, shown inFig. 2, it appears that the pH and salt effects are not significant at the95% confidence level. Therefore, the pH was set at 5.0 (pH of thewater) and no salt was added in the following steps (Section 2.3).
การแปล กรุณารอสักครู่..
