Purifying glassware in a high-temperature Carbolite oven has enabled Elga LabWater to stop using chromic acid for the preparation of samples in the R+D laboratory where new water systems are designed
Minimal total organic carbon (TOC) levels, which are used as an indicator of overall organic purity, are a key requirement for users of pure water in laboratories.
Elga's Purelab Ultra system achieves TOC levels as low as 1ug/litre.
In order to stop water samples being contaminated by organic compounds on the glassware, Elga used to soak it in chromic acid, which is both toxic and corrosive.
Now, following the recommendations in Preparation and Testing of Reagent Water in the Clinical Laboratory (CLSI 4th edition, 2006), sample bottles are rinsed in ultra-pure water and then heated to 450C for two hours in the high-temperature Carbolite oven.
Tests have shown that any organic contamination present after this procedure is not detectable, according to Paul Whitehead, R+D laboratory manager.
The equipment has a maximum temperature of 500C and a 60-litre capacity stainless steel chamber.
A PID controller is fitted to ensure temperature stability, and fan-assisted air circulation gives temperature uniformity better than +/-5C, as well as fast heat-up and recovery times.
Carbolite manufactures high-temperature LHT ovens in three sizes - 30, 60 and 120 litres, each with a choice of 400C, 500C and 600C maximum temperatures.
