Very small injected samples to study chloroquine and quinine in human serum using capillary-LC and native fluorescence

A comparison between HPLC with conventional fluorescence detection and capillary-LC (μHPLC) with native laser-induced fluorescence (LIF) detection was done to determine chloroquine (CQ) and quinine (Q) in human serum. HPLC experiments were run with parameters of the conventional fluorimeter set at the highest level of sensitivity. Results were compared with those obtained on μHPLC coupled to a ZETALIF (He–Cd 325 nm) detector which provided a 50-fold increase in sensitivity. In μHPLC-LIF injection volumes were 200 nL instead of 10 μL in conventional HPLC. The separation was completed within 3 min (6 min on HPLC). The limit of detection on μHPLC-LIF was 1.9 and 1.3 fmol for CQ and Q, respectively. Both experiments were validated on serum samples. The mean recovery was more than 95% for CQ and Q. The intra- and inter-day precision and accuracy were found to be within the acceptable limits (<10%).