Silver colloids and invisible ink

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00:00:00 Welcome
00:01:21 Abstract – Hi Ho Silver, away…
00:02:44 Agenda
00:03:51 O2Q: we’ll be hearing about silver nitrate in this talk but…
00:04:20 Invisible ink
00:05:37 George Vaux Bacon
00:06:28 Argyrol See:
00:06:57 Ionized Super Silver (with ozone!)
00:07:10 Argyrol
00:07:20 Hegonon – Schering – silver protein complex
00:07:30 George Vaux Bacon
00:08:04 George Vaux Bacon
00:08:17 GVB looking happier than his mugshot
00:08:26 George Vaux Bacon
00:08:46 Macrakis
00:09:11 CIA Declassifies Oldest Documents in U.S. Government Collection
00:09:34 CIA – “Secret writing document six”
00:09:57 Colloidal silver
00:10:21 Preparation of ‘silver’ colloids
00:13:14 John Turkevich – colloidal gold mainly
00:13:37 Turkevich – Gold Bulletin (1985 articles)
00:13:55 PhD Thesis: Victor Elias Torres Heredia Universidad Politécnica de Catalunya November 2011
00:14:33 Stabilization
00:14:59 Shape Control
00:15:11 Nanocubes
00:15:24 Tollens' reagent preparation
00:16:28 Aldehyde test – for the organic chemists only
00:16:46 Care! Silver nitride is formed on storage…
00:17:16 Form of silver produced
00:19:10 Merck's Report
00:19:41 Surface Analysis – AFR: Ph.D thesis (alloy catalysts)Thanks to Sherylene Wass, JMRC, Sonning Common (1978)Nominally 5% Metal(s)/SiO2 made by hydrazine reduction. This shows the ESCA peak for Ag 3d for a Pd80Ag20 catalyst
00:20:41 Surface: 5 – 10 atomic layers – this is the Ag/SiO2Mainly carbon and oxygen….
00:22:02 Silver is in an oxidized state…Variability is high for such measurements
00:22:51 The silver is in the oxide state
00:24:12 Adapted from: www.catalysiscourse.comProfessor J.W. Niemantsverdriet, TU Delft
00:24:46 More XPS (Applied Surface Science) – now 2012
00:25:16 And more Auger…Tufts
00:25:38 SEM Image of typical catalyst – AFR PhD thesisAverage particle size ~ 10 nm by number
00:26:01 Silver and photography
00:26:18 Staining
00:26:23 Skin on hand stained by silver nitrate
00:26:29 Medical uses of silver
00:26:50 “Papa Smurf” “Once in a blue moon”
00:27:10 Science 1933 Argyria
00:27:25 Not to be confused with the Blue Fugates
00:27:44 Stan Jones (politician)
00:28:12 Stan Jones
00:28:25 Disinfection
00:29:56 International report
00:30:07 International report
00:30:24 FDA – “Final Rule” 1999
00:30:56 FDA & 483’s
00:31:18 483 examples
00:31:50 Debunking sites!
00:32:30 Quackwatch (continued)
00:33:04 And the backlash from manufacturers!
00:33:29 Silver alloys
00:33:59 Platinum Metals Review
00:34:30 Summary
00:35:08 Thank You!
00:35:08 Thank you for your attentionAny questions?
00:35:56 Contact Information

In the early history of cryptography and ciphers then invisible inks using silver salts and other chemicals were used. Silver colloids were regularly used and abused in this area. Silver colloids are now finding application (and legislation) as batericides. We'll note that silver colloids are not actually silver (on the surface) and owe their bactericidal properties to dissolution of the Ag+ ion from silver oxide on their surface. Ag is also used in Pd-Ag alloys for catalyst and hydrogen purification uses - we'll explore these too.