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

The viability of tandem photochemical reaction-chemiluminescence detection was studied for a heterogeneous family of nitro compounds using chloramphen icol as a test substance. The 'on-line' chemical photodegradation of chlora mphenicol was performed in a flow injection assembly by using a photoreacto r consisting of a 725 cm x 0.5 mm id piece of PTFE tubing coiled around an 8 W low-pressure mercury lamp. Photodegraded chloramphenicol was detected b y oxidizing photo-fragments from the parent compound and their subsequent r eaction with a luminol-Co(II) system. The calibration graph was linear up t o 3 x 10(-5) mol l(-1) chloramphenicol, the limit of detection was 3 x 10(- 9) mol l(-1), the relative standard deviation was 1.8% for 2 x 10(-6) mol l (-1) of the drug and the sample throughput was 60 h(-1). The proposed metho d was used to determine chloramphenicol in pharmaceutical formulations and its application to other related nitro compounds was studied.