A Cheap Trick To Prevent Metals in Storage Being Damaged by Volatile Gases – (Notes to Self Series)

Acid-detector strips can be included in packing containers and work well to detect volatile organic gases by using a reflectance spectrophotometer. I love the fact that analysis tools sound like they’ve been invented by one of the writer’s of Doctor Who. If you haven’t come across one of these little devices before, click here to read more.

Organic gases such as acetic and formic acid are particularly damaging to lead and copper alloy objects so these very inexpensive strips which show results within a couple of days could save significant damage occurring to an object.

Damage to Lead from Organic Vapours

Damage to Lead

They do not provide direct readings, but change colour to indicate the range of pH being encountered i.e. blue to green to yellow as pH becomes more acidic.  They are sensitive to higher levels of relative humidity, but much less so with low RH. They are tolerant of quite a wide fluctuation in temperature.  They should not touch the object, but being inexpensive can be placed around the container to help to identify gas sources.

Full Article by Stephen Hackney. Colour Measurement of Acid-Detector Strips For The Quantification of Volatile Organic Acids in Storage Conditions. Studies in Conservation 61, Sup 1, 55-69. 2016