Abstract:

Objective To establish a method for the determination of 12 elements in special medical wastewater，including arsenic （As），silver（Ag），cadmium（Cd），titanium（Ti），nickel（Ni），phosphorus（P），chromium（Cr），selenium（Se），berylliu（Be），lead（Pb），vanadium（V），and barium（Ba），using microwave digestion-inductively coupled plasma-atomic emission spectroscopy（ICP-AES）. Methods The special medical wastewater was digested using HNO₃-H₂O₂ system under microwave irradiation. After optimizing the key parameters of the instrument，the ICP-AES method was used to determine the concentrations of the 12 elements. The accuracy and reliability of the method were verified by recovery experiments and repeated tests. A total of 48 wastewater samples from 12 medical institutions were detected and analyzed. Results The method showed good linearity in the concentration range of 0.10-3.00 mg/L，with correlation coefficients（r） ranging from 0.999 1 to 0.999 9. The detection limits were between 0.4 and 30.2 μg/L，the relative standard deviations（RSD） were between 0.413% and 4.476%，and the spiked recoveries were between 91.0% and 103.4%. In the 46 wastewater samples，barium（0.014-0.512 mg/L） and phosphorus（0.768-6.750 mg/L） were detected. Titanium（0.006-0.039 mg/L） was found in 8 samples，and total arsenic（0.016-0.073 mg/L） was detected in 3 samples. The determination results of the remaining eight elements were all below their respective method detection limits. Conclusion The use of the HNO₃-H₂O₂ digestion system simplifies sample processing.The method is accurate，sensitive，and environmentally friendly，making it suitable for the rapid and simultaneous determination of multiple elements in batches of medical wastewater.

Key words: Medical wastewater, Elements, Microwave digestion, Inductively coupled plasma atomic emission spectrometry