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Hi all, From a lab's perspective - as part of a validation study - losses on drying and/or grinding must be investigated. This can be done in a variety of ways and does include spiking a soil with a known concentration of a volatile standard (both deuterated and/or normal PAHs). Some labs may also spike all samples prior to prep (especially if using chemical rather than physical drying). In order to gain MCERTS accreditation for any analysis performed on a dry soil (however it is dried), the data for loss on drying/grinding must be presented to UKAS and be robust, defendable, and within MCERTS criteria. Obviously how each lab does this and the analysis (prep/solvents/instrumentation etc) may be unique to themselves. Claire Claire Stone PhD, BSc(Hons), AUS, MRSC Quality Manager i2 Analytical Ltd 7 Woodshots Meadow | Croxley Green Business Park | Watford | Herts | WD18 8YS | UK +44 (0)1923 225 404 | F +44 (0)1923 237 404 | E [log in to unmask] <mailto:[log in to unmask]> www.i2analytical.com <http://www.i2analytical.com/> uk.linkedin.com/pub/claire-stone/14/675/b61 <http://uk.linkedin.com/pub/claire-stone/14/675/b61> From: Contaminated Land Management Discussion List [mailto:[log in to unmask]] On Behalf Of Beriro, Darren J. Sent: 28 May 2014 17:30 To: [log in to unmask] Subject: Re: Interesting article on sample preparation Hi Peter, There is some literature on the effect of different solvent extraction techniques on the quantification of organics (see below - I think the second link is open access). One way recoveries / losses can be estimated is by the addition of an exotic standard (e.g. PAH where carbon is substituted with deuterium) prior to extraction. These recovery data are then accounted for in the final reported concentrations we see in the certificates of analysis. As far as I am aware - and some of the laboratories on the list may be able to comment / correct me - it is not common to add recovery standards to the soil prior to sample prep which was one of the reasons for the study. http://www.sciencedirect.com/science/article/pii/S0165022X02001094 http://www.hindawi.com/journals/ijac/2010/398381/ I don't think there's any intention to investigate extraction efficiency further, although It would be interesting to extend the study to examine the effect of sample preparation on different soil types as well collecting additional data on BaP to identify why the statistics show a significant effect overall but not for any one particular treatment type. Thank you for your comment. Darren From: Hewitt, Peter [mailto:[log in to unmask]] Sent: 28 May 2014 16:59 To: Beriro, Darren J.; [log in to unmask] Subject: RE: Interesting article on sample preparation Hello An extremely interesting article. Is there any intention to investigate the additional impact of different extractants on the results? Peter Hewitt From: Contaminated Land Management Discussion List [ mailto:[log in to unmask]] On Behalf Of Beriro, Darren J. Sent: 28 May 2014 12:03 To: [log in to unmask] Subject: Interesting article on sample preparation Dear all, I thought the list would be interested in an open access paper we have written. It's on the potential effect of sample preparation techniques on the quantification of PAH in soil and HHRA. You can download the paper from here: http://www.sciencedirect.com/science/article/pii/S0045653514004263 Best wishes, Darren Beriro Applied and Medical Geochemistry British Geological Survey Tel: 0115 936 3100 (ext. 3479) ________________________________ This message (and any attachments) is for the recipient only. NERC is subject to the Freedom of Information Act 2000 and the contents of this email and any reply you make may be disclosed by NERC unless it is exempt from release under the Act. Any material supplied to NERC may be stored in an electronic records management system. This message (including attachments) is intended only for the use of the individual or entity to which it is addressed and contains information that is confidential, privileged and/or proprietary to Laing O'Rourke. 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