Which filters are best to prepare samples for heavy metals analysis?

Filtering water samples before ICP-MS or HPLC analysis for heavy metals testing is good practice - to help protect these delicate instruments from damage caused by larger particles. However some filters can introduce interferences which may affect the results - so what type of filter is best for heavy metals analyses?

Why filter samples?

Samples taken in the field are often high in particulate matter. These particles can cause problems in delicate instrumentation such as HPLC or ICP-MS, so filtering samples before analysis avoids these potentially costly problems.  

What filters should I use for metal analysis?

Traditionally glass fibre filters have been used for this type of sample, but some can introduce trace metals into the samples and give false results. For this reason a polypropylene filter should be used. We recommend Whatman's GD/XP syringe filters - they have a pre-filter later before the subsequent fine layers to prevent blocking, and use PP filters not glass to minimize interferences. [caption id="attachment_10441" align="aligncenter" width="300"] The GD/XP Syringe Filter 3 layer filter stack system[/caption]   See the filters here, along with suitable syringes here.   If you have any questions about sample preparation or water testing, just contact us