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DEVIL: Duke Environmental Stable Isotope LaboratoryDepartment of Biology, French Family Science Center |
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Rates for Sample Analyses (effective 11/9/2009)Notes: all sample submissions except %C + %N must be accompanied by a fund code, P.O.#, prepay check, or wire transfer.
Additional services (charges for these are the same for all clients)
Purified gases for dual inlet must be in 6mm or 9mm, 8" long breakseals, or in vacuum flasks, with no H2O. Samples found to be impure must be discarded. Acid-treated samples must be thoroughly rinsed in deionized water and dried at ~60 degrees C. For acid-fumed samples where rinsing is not desired, the sample must be double-encapsulated in silver capsules. The second wrapping should be applied immediately before shipping. Acid fuming can also be performed here for $10 per sample (plus $10 weighing per sample for unweighed samples). All samples must be thoroughly homogenized, and milled or mortared to a fine grain size. Ammonia diffusion trap samples must be on paper filters using minimal acid. ENRICHED 13C OR 15N MUST BE IDENTIFIED WITH ESTIMATED APPROX. ATOM %. ADD $5 PER SAMPLE. Since running enriched samples requires a reconfiguration, we must assemble large batches before running, which will increase turnaround times. Large enrichments are not necessary and should be avoided. We intend to analyze samples of no more than 1 or 2 atom% enrichment, preferably less. Remember that natural abundance of 13C is ~1.1 atom% and 15N is ~ 0.37 atom%. The natural abundance range is generally less than +/-40 per mil within most natural systems (this would be equal to +/-40 x 0.0011% = +/-0.044 atom % for 13C; +/-40 x 0.00037%= +/-0.0148 atom % for 15N). For a +1000 per mil enriched sample, this potential variability induces a maximum error of +/-4% of the measured enrichment, where +1000 per mil = 2.2 atom % for 13C, and +1000 per mil = 0.74 atom% for 15N). In most cases, error will be far less. Prepay accounts are not affected by price increases until 3 months after the account starts.
** Consult with lab director for preparation guidelines. *** Consult with lab director regarding suitability of water samples. Samples should be provided in 12x32 mm septum vials with no air space. Add $2.50 per sample if supplied in other containers. In addition, there is a $2.50 extra charge if filtration is required. See preparation guidelines page for further instructions. Revised 1/12/2009 cwcook@duke.edu |