mercury analyser

Please have a look at this PDF attachment.

Its a good question

Please have a look of attached pdfs.

US EPA method 7473 with Direct mercury analyzer for solid, liquid and gas samples.

Mercury concentrations as ppm or ppb in soil might be measured by using ICP-AES or ICP=MS. It is the best analyzer in order to measure heavy metals in soils and other sediments

I agree with Dr. J. C. Tarafdar

its useful for me ... thanks for all

Determination of Mercury:

Reagents:

1. Mercury standard solution concentration (1000.00 µg.ml-1) preparation: 1.080 g mercuric oxide (HgO) was taken. Then, 70 mL 1:1 HCl, 24 mL1:1 HNO3, 0.5 g K2Cr2O7 were added to the flask, when it was clearly dissolved, then deionized water was added up to the constant volume of 1000 mL, shake well. This solution can also have called as 1 mg. mL-1 solution.

2: Preparation of Hg standard working solution: First, 10 ml of mercury standard solution (1 mg. mL-1) was transfer to 1000 mL volumetric flask, the preservation liquid was added (used) to raise the solution volume up to 1000 mL, shake well. The concentration of this Hg solution =10 μg·mL-1. Then, 10 ml of Hg solution (10 μg·mL-1) was poured into another 1000 mL volumetric flask and again preservation liquid was used to raise the volume up to 1000 mL, shake well. The concentration of this Hg solution = 0.1 μg·mL-1. Lastly, 10 ml of Hg solution (0.1 μg·mL-1) was poured into 100 mL volumetric flask and deionized water was used to raise the solution volume up to 100 ml. The concentration of this Hg standard solution = 0.01 μg·mL-1.

3. Flow liquid (2 % nitric acid): Simply, 20 mL of nitric acid (optimal pure grade) was poured into 1000 mL volumetric flask, and deionized water was used to bring the volume up to 1000 ml.

4. Reducing agent solution (0.5% K (Na) OH + 1% KBH4): First, 5.00 g K (Na) OH was taken and completely dissolved in deionized water, after we added 10 g KBH4, shake well and solution volume was made to 1000 ml using deionized water.

5. Preservation Liquid: Simply, 0.5 g of potassium dichromate (K2Cr2O7) was dissolved in a small amount of water, 50ml of nitric acid was added, diluted to 1000 mL with water and mixed well.

6. Acid mixture: Concentrated HCl was mixed with nitric acid at ratio of 2:1 (v/v) and then diluted with deionized water 1 time.

Procedure: An air-dried soil sample (0.500g) was taken in 50 ml tube, 10 ml acid mixture (HCl: HNO3) at 2:1 (v/v) was added to the tube and put in the water bath (boiling) for two hours. After two hrs., the tubes were removed and 10 ml preservation solution was added immediately. The solution was diluted to the specific level and then analyzed for Hg. Two blank reagent solutions were also prepared at the same time and finally analyzed before the soil sample using Atomic florescence spectrophotometer (AFS-930), Beijing.

Mercury standard solution for AFS callibration:

Five standard solution of 0, 0.1, 0.2, 0.4, 0.8 and 1.0 ng.ml should be used for AFS-hydride generation system. Take 0, 0.5, 1.0, 2.0, 4.0, 5.0 ml solution from Hg solution (0.01 ug.ml-1) in 50 ml volumetric flask, then add 2ml HNO3 (1:1) solution to each flask, then raise the volume up to 50 ml using distilled water. the concentration such solution will be 0, 0.1, 0.2, 0.4, 0.8 and 1.0 ng.ml-1.

Run these standard on the machine, then run the blank sample and then run the samples to get the data..

It is ana easy way to determine the Hg in the soil solution.

Thank u very much for your answer and reply. Is this procedure suitable for mineral fertilizers also ?

I found one protocol for determiantion of Hg and As in fertilizer. but i personally used for fertilizer analysis, it doesn't work well.

procedure:

Take 0.2g fertilizer (powder form) in 150 ml disgestion tube, then add 15 ml conc; HCl and also add 5 ml HNO3.

but as a added chemicals to the fertilizers, a sudden reaction started in the tube and white precipitate was made. then i didn't use this method.

Then professor told me to add 5 ml HNO3+ 5ml HClO4 or add 5ml HF and then digest the sample on 150-180 degree.but later i didn;t follow the protocol. I really appologize for not providing such a proper protocol for fertilizer analysis. If i find other protocol, i must send you.

You are asking for the BEST method. The only best method is CV-AAS vold vapour atomic adsoprtion spectrometry. It is because there is no need for sample digestion or treatment (except drying - freeze drying recommended). Stick with procedures and QA/QC standards desrcibed in EPA method 7473 (as adviced by Maurizio Perotti above). Any wet digestion procedures and analysis of Hg using ICP based analytical methods are highly risky - this does not mean they cannot be used.

But there are many points where you may lose analyte. Best method for determination of Hg in almost any solid material = CV-AAS.

Good luck!