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<p>[QUOTE=&quot;desertgem, post: 2665591, member: 15199&quot;]JMGallego said:</p><p><br /></p><p>&nbsp;&nbsp;&nbsp; Yes, the so-called &quot;sniffer&quot; (can be an analysis instrument called Surface Enhanced Raman Scattering, SERS <a href="http://jes.ecsdl.org/content/129/8/1716.short" target="_blank" class="externalLink ProxyLink" data-proxy-href="http://jes.ecsdl.org/content/129/8/1716.short" rel="nofollow">http://jes.ecsdl.org/content/129/8/1716.short</a> or even by Infrared reflectance spectra, <a href="http://www.sciencedirect.com/science/article/pii/S0010938X70800269" target="_blank" class="externalLink ProxyLink" data-proxy-href="http://www.sciencedirect.com/science/article/pii/S0010938X70800269" rel="nofollow">http://www.sciencedirect.com/science/article/pii/S0010938X70800269</a> ) will detect films of benzotriazole (BTA) on the surface of a coppe coin or in a coin contains copper (such a 90% silver coins). BTA does not &quot;disappear&quot;, it creates CuBTA by covalent bonds with copper atoms.</p><p><br /></p><p><br /></p><p><br /></p><p><br /></p><p>Do you have references for the part&nbsp; &quot;BTA does not &quot;disappear&quot;, it creates CuBTA by covalent bonds with copper atoms.&quot;</p><p><br /></p><p>BTA does combine with copper, but the copper can not then maintain the metallic bonding with the coin. That is why references also refer to this as a &quot;passive layer&quot;. The passive layer is insoluble in water, and in most but not&nbsp; all organic solutions, which leads me to believe that it is not permanent then it can be removed. I know its use has been explored for other coins, especially ancient coin bronze disease problems.&nbsp; I am not saying you are incorrect, just where you found the info as last I read on this a while back the bonding and structure of the&nbsp; cu-BTA&nbsp; was somewhat controversial. Thanks[/QUOTE]</p><p><br /></p>

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