초록
Gamma irradiation degradation of the extensively used muscle relaxant in the world methocarbamol (MET) was studied. MET aqueous solutions were irradiated by gamma rays emitted by a Cobalt 60 source at doses of 1-4 kGy. Our findings demonstrated that gamma irradiation degraded more than 98.5% of MET. Absorption spectra analysis revealed that when increased irradiation dose, the absorption bands declined with complete disappearance at 4 kGy dose. Additionally, the most radiolytic degradation rate was recorded at neutral pH, marked by Total Organic Carbon (TOC) removal rate of 98% reflecting the total mineralization of MET at 4 kGy. In-depth spectrophotometric analyses advocated a pseudo-first-order type of MET degradation kinetics. The obtained apparent rate constant value was kapp, MET = (0.02167 ± 0.0006) min-1. Gas chromatography-mass spectrometry (GC-MS) allowed the detection of 3-(o-methoxyphenoxy)-1,2 propanediol,2-methoxyphenol, 1,2,3 propanetriol, 1,2-dihydroxybenzene and 1,2,4 benzentriol identified as by-products generated during radiolytic degradation. Finally, an outline of the degradation mechanism was suggested according to the obtained by-products.