Dear Zolhizir

I use HF, HNO3+HCl (3mL+1mL) and HClO4

Dear Mr. Daud,

please give full particulars what your questions are aiming at. It is a mixture of different aspects that first and foremost need some streamlining prior to being made public. The dissolution of REE from the particulate matter refers to phases bearing REE, e.g., xenotime or monazite. It may be a newly-formed species of REE-bearing APS minerals. You need to know what the main object is. What does it mean Ba in SPM and PM 10, has it anything to do with the main title ? Ba and REEs you find in carbonatites. It is certainly not what are you interested in or? The Fe content in estuarine sediments has nothing to do with REE, it may range from background to almost ore grade. I suggest to be more focused in your Q & A launch to attract the interests of experts on the matter.

I try to help you figure out presenting a basic question and not to put you into some inconveniences.

Best regards

Harald G. Dill

Dear Dr Karbassi and Prof Harald G. Dill

Thank you very much on your feedback and commend, apologized to Prof Harald G. Dill. Those answers and idea are helping me for deep studies on REE and trace metal connectivity. I'm sure those will trigger out clearly on REE compartment from earth, crust and ocean (lithosphere), atmospheric and to the moon.

As you know, Fe and Ba are elements that roles as transporter and indicator for detecting REE in freshwater influence. REE are transported by Fe in every partition and compartment but Ba play as important roles when REE moving  in freshwater or ice melting. I'm still working on REE studies in this area, and try to understand on how the REE in particle and suspended particulate matter (SPM) are brought from northern to southern part as connected to Broecker (1986) on theory of "Conveyor Belt" 

Thank you again

Best regard's

Zolhizir bin Daud

Dear Researcher,

It is very difficult to dissolve REE by conventional wet digestion using HNO3-HF-HCLO4 combinations. We could completely dissolve rock samples using fusion with NaOH in nickel crucibles. Even you can fusion can be performed  on hot plate. There are other fusion techniques using Li metaborate and Li tetraborate or combinations. After fusion, all material can be dissolved in HCL. The only problem is high Na matrix  interferring in ICP-ICPMS analysis or contamination with Ni crucibles.

Tahir Zaidi

Dear Dr Tahir

My suggestion try to   use TetraFluoroBoric Acid (HBF4) if so hard to digest the particulate or particle  but its depends the size, shape and species of particle. I thought many researcher use or mix with internal standard e.g 0.5ml indium, rhenium or rhodium to avoid the matrix or fluctuate that interfering the ICP-MS. But i don't know it is fully effective or certain.

Zolhizir bin Daud

Dear Mr Daud,

we use High Pressure Microwave Digestion with a mix of HF(2ml)-HNO3(8ml) to achieve total digestion of SPM and sediments for REEs analysis by ICPMS. Keep in mind that ICPMS is strongly impacted by your matrix causing interferences that can not be overcome by internal standard. A high acidity of your disolved sample would end to significant changes of plasma energy causing unstability. Moreover, the final sample that will go to ICPMS should better be in HNO3 matrix rather than HCl cause Cl causes much more interferences. To avoid all these issues we use the microwave digestion as I said but we evaporate the acids after the digestion and dilute the sample in HNO3 1N. And of course, along with the samples, we analyse the BCR667 reference material which has certified values for all REEs.

Dear Eleni Prifti,

That true when using internal standard  actually not fully effective digestion. Anyway the precise and quality digestion of particulate and particle depends not only the shape, textural and geological form but also considered on the location where the particulate and SPM came from. My experience  working on REE in SPM  showing the samples particle from river are quite difficult to dissolve compared to samples of coastal and sea area. As you know, there were much organic complex in river particulates.

I try to apply the method from Loring and Rantala (1992) and modified some. where i use to leach or soak the filter paper with 2M HNO3  and stayed for overnight (24 hours) in beaker  then separate the dissolve filter paper from trapped particle or particulate, rinse with some deionized water. Removed the particle into teflon beaker then digested using combination concentrated of  ( HNO3 -HClO4 -H2O2) + HCl concentrated (depends)  for 2 hours then fully digest using HF concentrated. Then finalize it with Boric acid before diluting with 30 ml 0.5M HNO3. I try to avoid from using high combustion @ teflon bomb  method because the samples of  particle or SPM is tiny not more than 100mg as refer to Fukai et al., (2007).

Regard's

Zolhizir bin Daud

Dear All,

Thank's so much for the answers and ideas. Very useful for my research.

Regard's

Zolhizir bin Daud