Currently, we are using GF-AAS to detect trace metals in ppb level.
ICP or ICP MS is of course a better technique. By the way, how are you preparing your sample?
What type is the oil ? Which are the elements you are interested in ? Which concentration range are they supposed to be ?
Type of oil: Palm Oil
Elements: Ni and fe
Our routine checking is about ≤0.5ppm but currently we are participating in AOCS inter laboratory cross efficiency test. I suspect the metal content in that particular sample must be more than 1ppm. Is that possible to analyze the higher concentration using the GF-AAS by building new calibration curve 1 to 10ppm? Is that the detection of GF-AAS could be up to 10ppm?
Try increasing the amount of sample taking before sample pretreatment may help in the detection of the metals.
Its a Perkin Elmer automated system. Currently the setting is draw 20microlit of sample per analysis. Its a direct injection system without sample pre-treatment.
A simple way to increase 4x your actual analytical range is to inject 5 uL sample, but here you better add some solvent before pipetting to better clean autosampler tip.
Other option to reduce sensitivity could be not to use gas-stop during atomization.
Other option could be to use a less sentitive wavelength.
Other option could be to dilute more the sample.
Plenty of possibilities, but do not forget that absolute sensitivities depends form the element (not all elements have been made equal ...), so some advices could not pertain to all elements.
Regards,
Riccardo
Although ICP/MS is better but GF-AAS is also quite suitable for such range. You have to take care of analyte concentration in the sample, digestion procedure and more sensitive calibration curve.
Of course GFAAS is sensitive enough to determine that levels of metals, other question is wether it's a more or less suitable approach. I'll suggest you to use aqueous standards instead organic ones because ot the price of them, and IMHO i'd rather try FAAS or ICP if it's available. A procedure to perform it by FAAS outlined in this paper: "Determination of metals in used lubricating oils by AAS using
emulsified samples". Irene M. Goncalves, Miguel Murillo *, Angela M. González. Talanta 47 (1998) 1033–1042
Cheers,
Bavaani... Atomic absorption is a perfect and reliable technique to analyze metals in oil samples. Both flame and furnace are capable to do the atomization and hence the analyses. You may refer to the following articles as an example.
Evaluation of analytical procedures in the determination of trace metals in heavy crude oils by flame atomic atomic absorption spectrophotometry
American J. Analyt. Chem., 6(2015)325-333.
and
Determination of trace metals and their distribution in heavy crude oil distillates (350+) by atomic absorption spectrophotometry.
Applied Spectroscopy, 43 (1989) 1257.
Regards
It's possible to use GFAAS for analysis of trace elements in crude oil samples with very good acuŕracy and repeatability for Ni and Fe in the range of ppb .
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