Determination of mercury in mercury globules by energy dispersive X-ray fluorescence spectrometry

To meet the demand for mercury content determination in mercury globules within specific industrial fields and to overcome the limitations of the existing method (inductively coupled plasma atomic emission spectrometry, ICP-AES), which requires tedious dilution and the addition of stabilizers for handling highly acidic solutions, this study aimed to establish a rapid and simple method based on energy dispersive X-ray fluorescence spectrometry (ED-XRF). Solid mercury globules were dissolved with nitric acid using ultrasonic agitation at 80 ℃ for 40 min, and the resulting solution was diluted to volume. The mercury content was directly determined by ED-XRF. The limit of detection of this method was 1.068 mg/L. Results obtained by this method were compared with those from ICP-AES for the same samples, and statistical analyses including the for outliers (Grubbs test), F test, and t test were performed. The results showed that both methods exhibited good linearity within their respective ranges (correlation coefficient r>0.999). The Grubbs test, F test, and t test results indicated no significant difference between the ED-XRF and ICP-AES results in terms of precision and trueness. For highly acidic test solutions, ED-XRF allows direct determination without dilution or stabilizer addition, thereby effectively avoiding errors associated with the dilution process and problems related to solution stability. The proposed method is suitable for the rapid and accurate determination of mercury in mercury globules.