Whats the expiry on my pH buffers made from capsules?

[caption id="attachment_3034" align="aligncenter" width="300" caption="Reagecon buffer capsules"][/caption] I have some pH buffer capsules which I make up into liquid pH buffer solutions for calibrating my pH meter and I wondered what is the shelf life once it is made up? The reagecon buffer capsules are a simple way of extending shelf lifes of pH buffers. the powder is made up to a specified volume as required and the capsules have typically long shelf life's, ideal for occasional use as you would have in a school or college. Reagecon issue the following advice   Reagecon Buffer Capsules (pH 4.00, 7.00, 9.00 & pH 10.00) once reconstituted should be stored in an air tight container (in an upright position) at room Temperature, away from any strong light source (e.g. sunshine, UV lamp). They will have a shelf life of 3 months provided Good Laboratory Practise is strictly adhered to, it is strongly advised to record the date of reconstitution on the bottle, to close it immediately after every use and to discard the contents of the bottle when less than 10% of the original volume of the solution is left. This 3 month expiry date is valid provided the product is properly stored and handled in compliance with these instructions. This expiry date ceases to be valid if the product is damaged, contaminated or modified. Please note that Reagecon Buffer Capsules pH 9.00 & pH 10.00 (once reconstituted) are less stable than Reagecon Buffer Capsules pH 4.00 & pH 7.00 as these products absorb CO2 from the atmosphere, therefore it is imperative to follow the above recommendations in order to allocate a 3 month expiry date to these products Contact Camlab for any requirements for pH buffers, pH electrodes or pH meters and get a discount voucher to use on any pH product.