Spectroscopy and Spectral Analysis, Volume. 45, Issue 2, 420(2025)
Determination of S and the Correlation With Total Protein in Pet Feeds by Super Microwave Digestion ICP-OES
A novel method for determining the sulfur content in pet feeds was established using a super microwave digestion system and inductively coupled plasma optical emission spectrometry (ICP-OES) in the study. For the first time, we systematically investigated the effects of super microwave digestion conditions on residual carbon content (RCC) and residual acid (RA) in the digestion solution. We evaluated the digestion effects effectively and developed a new strategy for optimizing microwave digestion conditions based on these indicators. Furthermore, we thoroughly examined the influence of five different sulfur species on sulfur determination. We found that the emission intensity of sulfur was significantly enhanced by preparing low-valent sulfur standard substances under acidic conditions. However, when high-valent sulfur standard substances were prepared under acidic, neutral, or alkaline conditions, the emission intensity of sulfur remained relatively stable. This provided useful guidance for selecting preparation media and sulfur standard substances. Additionally, our research revealed that the super microwave digestion system effectively eliminated the enhanced emission intensity effect of low-valent sulfur under acidic conditions. In summary, the accurate determination of five different valence states of sulfur in pet feeds can be achieved by preparing high valence sulfate () standard substance under acidic conditions using the super microwave digestion system. The recoveries ranged from 86.5%~108%, and the RSD was between 1.69% and 4.18%. The detection limit was 6.2 mg·kg-1. Compared with the national standard method, this method had high sensitivity, low cost, environmental friendliness, and high work efficiency. Furthermore, a significant positive correlation was observed between sulfur and total protein content in pet feeds (correlation coefficient=0.819, p<0.01). This conclusion can provide new ideas and directions for accurately determining pet feed protein content.
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CHEN Shu-di, LI Jin-cai, CHEN Xiao-yan, LI Sheng, ZHANG Shi-wei, ZHENG Yan-jie. Determination of S and the Correlation With Total Protein in Pet Feeds by Super Microwave Digestion ICP-OES[J]. Spectroscopy and Spectral Analysis, 2025, 45(2): 420
Received: Jan. 25, 2024
Accepted: May. 21, 2025
Published Online: May. 21, 2025
The Author Email: CHEN Xiao-yan (634403201@qq.com)