Determination of 14 Micro Rare Earth Elements in Human Feces by ICP-MS

Human feces were collected in acid-washed plastic containers for three consecutive days from 30 subjects of Zhenjiang area, the fecal samples for the three-days period were pooled, weighed and homogenized, then dried, ground and ashed at 550 ℃. The samples were wet digested by HNO₃ before determination. The soloution was directly analyzed by ICP-MS for the determination of 14 micro rare earth elements in human feces with rhenium internal standard calibration. The detection limits of REEs are 0.09 ng·L^{－1 175}Lu,—1.9 ng·L^{－1 147}Sm. ∑LREEs is approximately 5.9 times greater than ∑HREEs in human feces.