Highly sensitive simultaneous electrochemical determination of myricetin and rutin via solid phase extraction on a ternary Pt@r-GO@MWCNTs nanocomposite

Tursynbolat, Satar; Bakytkarim, Yrysgul; Huang, Jianzhi; Wang, Lishi

The pre-concentration time and potential were studied in the pH 3 BR buffer solution containing 50 mM myricetin and rutin. In concentration potential on the oxidation peak currents of myricetin and rutin using the optimized pre-concentration time. In Fig. 7B , the oxidation peak current increased until À0.3 V, after which the oxidation peak currents gradually decreased. Therefore, the optimal pre-concentration potential for determination of myricetin and rutin was À0.3 V. The simultaneous quantitative determination of myricetin and rutin at the Pt@r-GO@MWCNTs/GCE was investigated via DPVs. From Fig. 8E , with an increase in concentration of myricetin and rutin, the corresponding oxidation peaks current gradually increased in intensity. Fig. 8F shows that the concentration of myricetin and oxidation peak current exhibited two linear detection ranges of 0.05e10 and 10e50 mM with linear equations of I p (mA) ¼ 2.0561C (mM) þ 1.6368 (R 2 ¼ 0.9958) and I p (mA) ¼ 0.5643C (mM) þ 17.2910 (R 2 ¼ 0.9731), respectively. From Fig. 8G , the concentration of rutin and oxidation peak current showed two linear detection ranges of 0.05e10 and 10e50 mM with equations of I p (mA) ¼ 2.4047C (mM) þ 3.5326 (R 2 ¼ 0.9944) and I p (mA) ¼ 0.6247C (mM) þ 21.6050 (R 2 ¼ 0.9906), respectively. The detection limits of myricetin and rutin were 10 and 5 nM (S/N ¼ 3), respectively. These results indicated that the Pt@r-GO@MWCNTs nanocomposite modified electrode showed higher sensitivity and selectivity for both myricetin and rutin. Moreover, compared to other reported determinations of myricetin or rutin, our Pt@r-GO@MWCNTs/GCE can realize the simultaneous determination of myricetin and rutin with lower detection limits and the wider linear ranges (Table 1) [16,36,37,56e59] . The electrode modified with the Pt@r-GO@MWCNTs nanocomposite showed improved detection sensitivity due to the pre-concentration ability and solid-phase extraction.