Determination of elemental impurities Cd, Pb, As, Hg, Co, V, Ni, Pd, Ru, Ag, Pt, Mo, Al, and Fe in highly potent analgesic activity agent by microwave-induced plasma optical emission spectrometry (MIP OES)

Two methods for quantifying elemental impurities in a highly potent analgesic activity agent (2R,4aR,7R,8aR)-4,7-dimethyl-2-(thiophen-2-yl)octahydro-2H-chromen-4-ol have been developed using acid decomposition assisted by microwave digestion system or heating in metallic block followed by analyte determination using microwave-induced plasma optical emission spectrometry (MIP OES). Both methods have been validated. The fast linear interference correction (FLIC) and inter-element correction (IEC) methods have been used to take into account possible spectral interferences. Arsenic and mercury have been determined using the multimode sample introduction system (MSIS). The detection limits have been calculated (µg L−1) – 5.4 for Cd, 5.1 for Pb, 11 for As, 1.3 for Hg, 10 for Co, 2.4 for V, 1.4 for Ni. The accuracy of the results was established using an independent inductively coupled plasma mass spectrometry (ICP-MS) method. The relative standard deviation (RSD) (n ≥ 4) was ≤ 12% for Cd, 3.8% for Pb, 6.2% for As, 11% for Hg, 3.0% for V (sample decomposition assisted by heating on metallic block), and 10% for Ni (sample decomposition assisted by microwave radiation). It was shown that the concentration of Cd, As, Hg, Co, V, Ni, Pd, Ru, Ag, Pt, and Mo as impurities in (2R,4aR,7R,8aR)-4,7-dimethyl-2-(thiophen-2-yl)octahydro-2H-chromen-4-ol was lower than the upper limit concentration.