Analysis of inorganic elements in different batches of earthworm polypeptides by ICP-MS combined with chemometrics technology

To establish a method for determining 26 inorganic elements in earthworm polypeptide and determine the elemental content in different batches of earthworm polypeptide, microwave digestion method was used to pre-treat the samples, and ICP-MS method was used to determine the content of 26 elements in different batches of earthworm polypeptide. The linear relationships of 26 elements were good in the range of 0-1 000 μg·L^-1, with R² greater than 0.999, precision RSD 0.21%-2.71%, repeatability RSD 0.19%-4.69%, stability RSD 0.11%-4.24%, and recovery rates of 82.41%-116.16%. The data was plotted using Origin 2022 software to characterize the distribution of elements content. SPSS 27.0 was used for principal component analysis, and SIMCA 14.1 software was used for OPLS-DA analysis. The results showed that among the 26 elements, the higher content of earthworm polypeptide was K, Na, and Ca, followed by Zn, Fe, Al, B and other trace elements, In, Sc, Co, Pb, Bi and other elements had little or no detectable content, and there were differences in the content of polypeptide in different batches. This study provides a theoretical basis for the production quality control, quality evaluation and drug efficacy application of earthworm polypeptide through the determination and analysis of the elements and content of earthworm polypeptide.