I digested some reddish brown (floodplain, exposure?) Pliocene sediments for trace elements/Sr-Nd-Li isotopes using (MC)ICPMS. My procedure is to use 10%HCl to remove carbonates and then weight ~50 mg powder samples in bomb, adding 1mL HNO3 and 1 mL HF (we have no HClO4) to the bomb to attack the powders and sealed into steel bombs at 195°C for at least 48 hours. then open and dry them on hot plate to remove F-related. It seems very clear solutions for most samples including AGV-2 standards, but the trace elements data are strange: Li, Rb, Sr and many elements are analyzed match well with references, but REEs and some elements are all much lower than references. thus it must be some problems of digestion process. some heavy minerals cannot be dissolved? or some kinds of flurides formed? the solutions seem no solid, but some are not so clear, but no solids by eyes.
Please look at the following below links which may help you in your analysis:
http://weppi.gtk.fi/publ/foregsatlas/articles/Analysis.pdf
https://pdfs.semanticscholar.org/8f8a/ad64eaa88bb5bd37d4124ebc5de5b8e8e09f.pdf
https://www.iic.cas.cz/~grygar/Catena_Moravia_2010.pdf
Thanks
thank you very much for sharing these valuable papers with me! I will read these materials and search more operation procedures. contact later. Isam Eldin Hussein Elgailani
You can add 4%boric acid for dissolution of fluorides formed. It is recommended for digestion of siliceous matrix eg. sediments
for best , I can recommend you to follow and have a look on paper by pruseth etal..
and for digestion you can follow USEPA 3051(A/B), 3052 whatever suits according to your protocol designed.
regards!
Can you use microwave digestion system? Usually for acid sample preparation use concentrated HNO3, HCl and HF acids.
You may have problems:
1. You have not completely dissolved quartz matrix. Perhaps you should use more hydrofluoric acid and add hydrochloric acid.
2. Fluorides are not sufficiently neutralized, 4% boric acid (5 or 10 ml) should be used and after the sample should be dried.
3. A lot of dissolved organic matter in the solution. Should be added dropwise H2O2 when heated on the stove (approximately 100-120 C) until the violent reaction stops.
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