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<p>[QUOTE=&quot;BadThad, post: 3102768, member: 17261&quot;]As I recall they use FTIR ATR - which is not a very sensitive technique. That&#039;s why they picked grease in the PCGS video, they slather on a TON to a coin and say &quot;see how it&#039;s detected&quot;. Not hard to detect if there&#039;s a 2+mm layer!&nbsp; If they would have picked Verdi-Gone in that video, they would have not received ANY signal at all as that product had almost no IR detectable materials in it. I was LMAO that it was even in their library.....most likely nothing but unmatchable signal noise.</p><p><br /></p><p>Very thin layers cannot be detected with reflectance photospectroscopy - there&#039;s just not enough signal getting back to the detector to differentiate from the noise produced. It&#039;s hugely different from normal FTIR where the incident light passes through the sample.</p><p><br /></p><p>For sure they&#039;re not using MS! The people running the Sniffer are not chemists - just regular PCGS employees trained on running the instrument. Running a mass spec is pretty serious business - even for an analytical chemist. Many chemists that run MS are dedicated to doing only that. The equipment and people that run it are very expensive![/QUOTE]</p><p><br /></p>

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