It should be pointed only that obviously matrix matched standard solution should be used for calibration, which mean that ascorbic acid should be added to all aqueous standard solutions to ensure the same sensitivity for total Sn determination.
In this case, the slope of standard addition curve for beverages like wine and beer can be accepted to be approximately equal to those of aqueous standard solutions matched with ascorbic acid.
The limits of detection and quantification defined as 3rblank/m and 10rblank/m (N: 12) (where rblank is the standard deviation of twelve replicate measurements of the blank and m is the slope of the calibration curve) were found to be 0.33 and 1.10 lg L1, respectively.
Because the amount of tin in 50 mL of sample solution is measured in 1.0 mL of acidic methanol after preconcentration by CPE, the preconcentration factor was calculated by a factor of 50.
The enhancement factor (EF) was 40, which was calculated by using the ratio of
direct calibration curves’s slopes obtained with and without preconcentration.
Similarly, the results obtained for matrix-matched calibration curve with acceptable decrease in sensitivity are presented in Table 2.