Introduction: A sensitive analytical method based on functionalized multi walled carbon
nanotubes reinforced hollow fiber solid/liquid phase microextraction (F-MWCNTs-HF-SLPME) forwarded
with HPLC-DAD for analyzing phenazopyridine from urine is presented.
Materials and Methods: The extraction of phenazopyridine is performed using specially designed FMWCNTs-
HF-SLPME device constructed as follows: the functionalized multi walled carbon nanotubes
(F-MWCNTs) were immobilized into the pores of 2.5 cm hollow fiber micro-tube using capillary forces
and ultrasonication, then, the lumen of the micro-tube was filled with 1-octanol with two ends sealed.
Subsequently, the device was placed into 10-mL of urine sample containing the analyte with agitation.
After ending extraction, the device was removed, rinsed, sonicated in 250 µL of organic solvent and
analyzed directly by the separation system.
Conclusion: Different parameters affecting the performance of the developed method were optimized.
The method showed good linearity with (R2) 0.999 and good repeatability with (RSDs) from 3.7 to
0.9% at analyte concentration ranged from 0.01 to 10 µg L-1 of spiked urine samples. The limit of detection/
limits of detection quantitation LODs/LOQs was 0.02/0.09 µg L-1. In comparison with reference
methods, the developed method is considered as a promising microextraction technique for determination
of trace phenazopyridine in human urine using a common HPLC without further cleanup procedures