To evaluate the presence of other counter ion that could resulted in better efficiency in ion exchange, the clhoride was change by nitrate anion as exchange group when it was observed that the analytes retention decreased by 32% for AMPA in both pH values, whereas for GLYP the exchange group had no significant influence and the signal decreased of 3 and 0.
1] it was observed that the AMPA signal remained practically constant and the GLYP signal decreased 'Ca' 15% (Figure 1).
0 mL was selected, which results in recoveries percentage of 30% and 40%for AMPA and GLYP, respectively (Figure 2).
48% for GLYP (Figure 5A), indicating that part of analytes were still attached to the resin after the elution process.
0 mL there was a significant gain in the recovery percentage for both analytes, reaching values of 97 [+ or -] 3% for GLYP and 88 [+ or -] 10% for AMPA (Figure 5A).
The final condition for extraction of AMPA and GLYP are presented in Table 1; under these conditions it was possible to achieve analytes concentration factors of 90 and 97 times for GLYP and AMPA, respectively.
When the proposed method was applied to determine AMPA and GLYP in water samples it is showed adequate, mainly because the sample enrichment factor was about one hundred times, which permitted to get the chromatographic determination of analytes in tap water samples (Table 2, Figure 6) that presents very low concentration of the analytes.
0% for GLYP (Table 2), which can be considered excellent for quantitative analysis for analytes with low concentration.