CL sensitisation of tris-(bipyridyl) ruthenium (II) - cerium (IV) reaction system by AgNPs for determination of GFX.

The flow injection combined with tris-(bipyridyl) ruthenium (II)-cerium (IV) chemiluminescence (CL) method based on the sensitisation of silver nanoparticles (AgNPs) has been established for the quantitative analysis of gatifloxacin (GFX). AgNPs were synthesised using the reaction between ammonia gas and silver nitrate solution and was used to increase the CL intensity of the proposed system. The enhancement of CL intensity was linear with the concentration of GFX added. Effects of different experimental parameters were studied. Under the optimal conditions, the linear relationship was established between the concentration range of 1.4 × 10-10-4.5 × 10-8 M, with the correlation coefficient (r2) 02E9999. The limit of detection was found to be 4.6 × 10-11 M. The relative standard deviation obtained was 3.2% for six replicate measurements of GFX (1.2 × 10-9 M). The proposed CL method was applied to the commercial drug and the result was in agreement with the labelled amount. The technique was further adopted to the analysis of GFX in spiked urine samples. Negligible interference was found (variation in CL intensity <5%) from a few common foreign excipients applied in preparation of pharmaceutical drug. The comparative results with a few reported methods indicates that the proposed method is more sensitive than other methods..