thin-layer chromatography;
2D TLC;
correlation of retention in normal- and reversed-phase chromatography;
cyanopropyl-bonded polar stationary phase;
pesticides;
D O I:
10.1556/JPC.17.2004.5.2
中图分类号:
O65 [分析化学];
学科分类号:
070302 ;
081704 ;
摘要:
Eighteen pesticides have been separated by two-dimensional thin-layer chromatography on a moderate polarity CN-modifled silica gel. CN-silica is widely used as a adsorbent in both normal- and reversed-phase chromatography. Large selectivity differences are obtained by combination of both NP and RP modes on cyanopropyl-bonded polar adsorbents. The greatest spread of points was obtained by combining nonaqueous normal-phase mobile phases (tetrahydrofuran or ethyl acetate in n-heptane) and aqueous reversed phases (a polar solvent (methanol or acetonitrile) in water), both on thin layers of cyanopropyl-bonded polar adsorbent. Correlations of R, values in NP and RP systems were used for practical separation of a mixture of eighteen pesticides by 2D TLC on this adsorbent. Plates were scanned and videoscanned to show the real pictures of the 2D TLC separation.