【摘要】 本文在改进铜的碘量法分析的基础上,建立起无铬木质素中铜的分析方法,对于研究和改进无铬木质素的性能有重要作用。其方法是:在酸性条件下,先以（NH₄）₂S₂O₈氧化分解木质素,再以NaCl除尽多余的（NH₄）₂S₂O₈,适度浓缩驱赶HAc。尔后调整PH,以NaF+K₂[CH（OH）COO)₂为掩蔽剂兼缓冲剂,KSCN为沉淀剂,倾入准确的过量Na₂S₂O₃标准溶液,淀粉为指示剂,用标准I₂液滴定之。该法抗干拢性强,终点鲜明,重现性好,检出下限达1mg铜,完全满足无铬木质素中铜分析的要求。更多还原

【Abstract】 The copper in the lignosulfonate can be determined by the indirect iodometric method. To decompose the sample, we can put in some H₂SO₄ （1: 1）and some solid （NH₄）₂S₂O₈, which is a strong oxidant in an acidic medium. The interference from the iron （Ⅲ） in the sample can be oliminated by the addition of a mixed masking agent NaF+K₂ [CH₂ （OH） COO]₂. And the iodine absorbed by the solid CuI can be released by the addition of thiocyanate ion.更多还原