Preferred cationic sequestrants are quaternarynitrogen compounds including medium or long chain alkyl groups.
首选季铵盐阳离子螯合剂的氮化合物，包括中型或长链烷基。
2
Structute of nitrogen heterocyclic ring quaternary ammonium salt cationic surfactants was identi fied by mass spectrography, nuclear magnetic resonance spectra, infrared spectra and etc.
用质谱法、核磁共振波谱法、红外光谱法等，确定了未知氮杂环季铵盐型阳离子表面活性剂的结构。
3
Quaternary red clay total nitrogen content was highest, but the available nitrogen content was lower than Granite soil and Purple sandy shale soil.