Hi Ashish,

it depends on the required accuracy and sample type. You might either consider standard XRF analysis or XRS (combined with microprobe).

Regards

Stefan

many of the metal can be analyzed by titration and below link may help you

http://www.google.co.in/url?sa=t&source=web&cd=4&ved=0CEQQFjAD&url=http%3A%2F%2Facademic.cengage.com%2Fresource_uploads%2Fdownloads%2F0030355230_17074.pdf&rct=j&q=determination%20of%20antimony%20by%20titration%20filetype%3Apdf&ei=XQOCTrFy5ZOJB7vxuPgO&usg=AFQjCNHULJ9qiIKIImwbhTka5cAS1Y2Ugg&cad=rja

Regards

Selvan

Is there really somebody left who uses "wet chemical analysis"?

I didn´t mention it because it seems somehow "outdated ":-)

try to use ICP-MS if the sample can be dissolved in water

Dissolve about 500 mg of Antimony Potassium Tartrate, accurately weighed, in 50 mL of water, add 5 g of potassium sodium tartrate, 2 g of sodium borate, and 3 mL of starch TS, and immediately titrate with 0.1 N iodine VS to the production of a persistent blue color. Each mL of 0.1 N iodine is equivalent to 16.70 mg of C8H4K2O12Sb2·3H2O.

above is for Antimony Potassium Tartrate and the below USP monograph may help you

http://www.uspbpep.com/usp32/pub/data/v32270/usp32nf27s0_m5290.html

Regards

Selvan

Dear Stefan,

wet chemistry is alive and many of the pharmacopeias is having classical methods of analysis and also working good;

wet chemistry is nothing but chemistry

instrumental analysis is an engineering and chemistry = analytical instrumental chemistry

Regards

You're not interested in the actual compounds of the antimony? Just the elemental composition? Then I would go with Stefan on the XRF. If you were, however, interested in the compounds (e.g. antimony in ore) then you could consider XRD as well. If you can dissolve the sample in an acid, then ICP-OES could also work.

Dear Riina, I want to analyze antimony in ore (the ore is rich in lead, silver, antimony and arsenic). Can you tell me the dissolution method for antimony? So that I could analyze antimony in ICP-OES. I have tried with aqua-regia and hydrochloric acid but not got good results.

I would have also suggested the use of aqua-regia. In my experience, dissolving ore samples is quite challenging because of the variety of different compounds in them. I have been able to dissolve small quantities of iron ore in hot hydrochloric acid (followed by titration because I was interested in Fe(II) concentration of the ore). Did you try heating the acid before dissolution? I would still recommend XRD because you might benefit more from that. If you're dealing with an ore sample, XRD could provide you with valid information on metal sulfides, oxides, sulfates etc.

Riina, I have tried all these methods but could not be able to analyze antimony. I have also tried to dissolve pure antimony powder in aqua-regia and HCl, but antimony not dissolved completely in both medium. Actually, the sample I want to analyze having approximately 40% antimony. Is there any other acid media to dissolve antimony?

I used a very concentrated HCl (10 M) and dissolved for 20 min continuously heating the solution. Copur et al. (1995) have reported in Ind. Eng. Chem. Res. that close to complete dissolution of stibnite was achieved with concentrated HCl. If you have, however, failed in dissolving your ore sample then I'm afraid there isn't much more I can do.

The best way to analyze this sample is to make a peroxide fusion in an zirconium crucible after that you leach out the sample in diluted hydrochloric acid .You can determine the antimony by ICP or if you want a better result by titration.If you got no fusion possibilyties try cooking with sulfuric acid.Kind regards Peter van Houwelingen

Hi Joshi,

Besides the reference Riina already gave you. There is a slightly more actual reference:

Copur et al: Ind. Eng. Chem. Res., 1997, 36 (3), pp 682–687

Maybe the process has improved?

Have you tried the "recipe" of Wood et al: Economic Geology and the Bulletin of the Society of Economic Geologists (November 1987), 82(7):1864-1887???

I think, some of the methods should work. How is your ratio between solvent (acid) and solid phase? Maybe your are just on the wrong side of the mixture. This is because you wrote, you couldn´t achieve complete dissolution. Could be a simple problem ....

Another suggestion: Have you talked to someone who uses microwave sample prep?

Regards

Stefan

I find Peter's suggestion on the sulfuric acid cooking really interesting. I might suspect the dissolution to be based on protons which might suggest hydrochloric acid to be more effective as it is a strong acid with complete dissociation. With sulfuric acid only the first proton represents a strong acid. Consequently, hydrochloric acid should yield better results with the same proton concentration. Too bad that things hardly ever are so simple, though.

Stefan raised a good point about the liquid/solid- ratio.

You could, by the way, use SEM coupled with EDS to determine the antimony concentration, too. It's a possibility but I wouldn't use it as my primary analysis tool because of problems with getting a representative sample.

I would believe the wet chemistry proposed by Selva (i.e. the titration with iodine)

Don't you have to have an aqueous sample for titration? If the problem originates from not being able to dissolve the ore sample, titration offers very little help.

I would try a perchloric acid / nitric acid digestion...take the mix to near dryness, but not dry!....two problems going to complete dryness, first Sb can volatilise in an open digestion and you will lose it , secondly perchloric salts are explosive. Then take the salts produced up in HCl. This is commonly refered to a 3-acid digest in geochem circles. I too would have expected Sb to dissolve in aqua regia, but if it didn't it must be trapped in some sort of refactory matrix. You may need to try a bit of HF, particularly if there are any silicates involved. You may need a very high final concentration of HCl in solution (20-50% by volume), partiularly since your mixture contains lead and Ag, otherwise these will precipitate out as chlorides and may co-precipitate with your Sb. Be very careful working with HF if you need to. Wear nitrile gloves, preferably double glove, have calium gluconate on hand for your skin if you suspect you may have got any on yourself...it won't burn straight away, will go pink and itchy and start to crystalise CaF2 out in your body....and you won't know that you have seriously hurt yourself until it is too late. If you work with perchloric acid you should have a specialised fume hood where the ducting is washed out with water or caustic because metal perchloric salts can accumulate in fume hoods and cause an explosion at a later date. Microwave digestion in a sealed vessel would be a good option because it increases pressure, prevents going to dryness and any volatilised species can't get out. A fusion is an option for an ore that still won't dissolve....but I am not 100% sure whether all of the Sb would be retained in the melt...I would suggest a high flux to sample ratio to guard against that.

what you want tell me ？

I can't understand

For a solid sample I would not use a liquid digest method. I would measure directly in the solid phase. We use a X-Ray Fluorescence (XRF) analyzer. The Thermo Niton XL3t works great.

I did so experiments on that and got good results by using multi-acid digestion procedure using HCl in excess quantity. I think for high concentration antimony analysis titration method is best followed by multi acid digestion procedure.