<?xml version="1.0" encoding="utf-8"?><!DOCTYPE Zthes SYSTEM "http://zthes.z3950.org/xml/zthes-05.dtd">  <Zthes><term><termId>31306023</termId><termName>chelating agent</termName><termType>PT</termType><termNote><![CDATA[ Organic chemical compounds capable of forming coordinate bonds with metals. Chelating agents are used to sequester or remove residual trace metal ions from materials to which they have attached. In a conservation context, uses of chelants include stabilizing of paper containing iron-gall ink, removal of iron residue from platinum prints; treatment of excavated copper objects.  ]]></termNote><termCreatedDate>2026-03-30 20:22:20</termCreatedDate><relation><relationType>UF</relationType><termId>31306024</termId><termName>agent, chelating</termName><termType>ND</termType></relation><relation><relationType>UF</relationType><termId>31306025</termId><termName>chelants</termName><termType>ND</termType></relation><relation><relationType>UF</relationType><termId>31306026</termId><termName>sequestering agent</termName><termType>ND</termType></relation><relation><relationType>UF</relationType><termId>31306027</termId><termName>sequestrant</termName><termType>ND</termType></relation><relation><relationType>BT</relationType><termId>31298939</termId><termName>materials by function</termName><termType>PT</termType></relation><relation><relationType>NT</relationType><termId>31320233</termId><termName>alpha-lipoic acid</termName><termType>PT</termType></relation></term>  </Zthes>