Determination of Mineral Elements in Fermented Liquid with Temperature-Controlled Wet Digestion and Flame Atomic Absorption Spectrometry

Temperature-controlled HNO3-H2O2 wet digestion and flame atomic absorption spectrometry (FAAS) were employed in the determination of mineral elements in the fermented liquid residue of livestock dung. The 8 most common mineral elements-K, Na, Fe, Mn, Cu, Zn, Ca and Mg-in fermented liquid were selected for analysis, and the experimental results showed that the correlation coefficient (r) of each mineral element’s quantitative standard curve was >0.9993, the quantitation limit was 0.90-67.0 ng/L, the relative standard deviation (RSD) was 0.79%-2.51%, and the standard addition recovery rate was 95%-103%. It was found that the average content of the 8 mineral elements in fermented liquid was in a descending order of K, Na, Ca, Mg, Fe, Mn, Zn and Cu.