Enhanced chemiluminescent determination of chloramphenicol and related nitro compounds by ‘on-line’ photochemical reaction

Abstract

The viability of tandem photochemical reaction–chemiluminescence detection was studied for a heterogeneous family of nitro compounds using chloramphenicol as a test substance. The ‘on-line’ chemical photodegradation of chloramphenicol was performed in a flow injection assembly by using a photoreactor consisting of a 725 cm × 0.5 mm id piece of PTFE tubing coiled around an 8 W low-pressure mercury lamp. Photodegraded chloramphenicol was detected by oxidizing photo-fragments from the parent compound and their subsequent reaction with a luminol–Co(II) system. The calibration graph was linear up to 3 × 10⁻⁵ mol l⁻¹ chloramphenicol, the limit of detection was 3 × 10⁻⁹ mol l⁻¹, the relative standard deviation was 1.8% for 2 × 10⁻⁶ mol l⁻¹ of the drug and the sample throughput was 60 h⁻¹. The proposed method was used to determine chloramphenicol in pharmaceutical formulations and its application to other related nitro compounds was studied.