Dear Manish, I recommend you to read to my colleague Gustavo Delgado I give you the link http://www.lamjol.info/index.php/UNIVERSITAS  the suggest use the Maple 13 programm.

Respected Dr. Gonzalez, Thank you very much for this.

Aerosol which is usually colloids of fine solid particles with the range of 0.001 to 100 microns in size. These are inorganic particles with very low concentration. In this regard not much work has been carried out. However the instrument like ICP-MS can be try which can analyse Ca and Mg of your concerned. For other ions and in this very very low concentration some method have to be evaluated. Which can determine the ions in part per trillion

Dear Manish,

I guess you want to analyze on metals in PM. Voltammetry might be a relatively cheap alternative for ion chromatography and surely compared to ICP-MS. This is the technique where Carlos Gonzalez is pointing to. See for performance characteristics in the air quality field for instance: http://www.sciencedirect.com/science/article/pii/S1352231006003943, where voltammetry is compared with ICP-MS. For anions, there is hardly an alternative to ion chromatography, as far as I know.

If I understood well, what you want to determine is the concentration of elements such as sulfur or chlorine. A rather cheap alternative is x-ray fluorescence, which would not only give information on these lements, but also many others including metals. Of course, it is more difficult to obtain data about the chemical state of the elements, although it is possible using wavelength dispersive spectrometers. Another advantage of XRF is that it is not destructive, so you can further analyze your samples with other methods. However, it is necessary to deposit the samples onto special filters, such as teflon or polycarbonate. But this a fast, low-cost alternative.

Dear Dr. Miranda,

I have to analyze inorganic ions like Sulphate, nitrates, chlorides, Bromides, ammonium, calcium and Magnesium in ionic forms. We have Ion chromatograph with us, but there is some problem in it which cannot be resolved now. so I am looking for some alternative options.

Dear Dr Saxena,

All parameters can be done together with the help of Ion Chromatograph. As far as the analysis of sulphates and nitrates from spectrophotometer is concerned, it is ok for higher concentrations i.e. ppm level, but in the atmospheric aerosols concentrations may be in ppb which is not possible to be analyzed with spectrophotometer. Second thing is that, sample size is very less in aerosol samples. spectrophotometer will not fulfill the purpose. Regarding Ca and Mg are concerned AAS gives total Ca and Mg. I am looking for Ca+2 and Mg+2.

Dear Manish,

Your question evokes old memories of methods almost forgotten (by me too), like nephelometry for sulfates and chlorides. If you cannot fix your IC, than this may be a valid alternative, It's anyway interesting to look into these old methods. See for instance this one; "THE CONCENTRATION OF CHLORIDE, SODIUM, POTASSIUM, CALCIUM, AND SULFATE IN RAIN WATER OVER THE UNITED STATES" link:

http://journals.ametsoc.org/doi/pdf/10.1175/1520-0469%281958%29015%3C0417%3ATCOCSP%3E2.0.CO%3B2

The authors claim a reasonable uncertainty of about 10%, and that's not so bad after all.

You mention that you need the concentration of the Ca and Mg ions, but for what reason and at what dilution of the sample? and at what pH? and should this be identical to the situation at which IC works?

Harry, in aerosol Ca and Mg are present usually in very low concentration. Perhaps in part per trillion. And pH  is usually  mildly acidic to neutral and it depend upon the sources of aerosol ,furthermore,this may not be identical to the satuation at which IC work.

@Virendra

Calcium concentrations can be quite high and in in that case the aerosol is alkaline because of its presence as CaCO3.

Chemical characterization of the inorganic fraction of aerosols and mechanisms of the neutralization of atmospheric acidity in Athens, Greece

http://www.atmos-chem-phys.net/7/3015/2007/acp-7-3015-2007.html:

"In both campaigns, calcium was found to be the predominant component of the coarse fraction while crust-related aluminosilicates and iron were the other major components"

Also Mg can be substantial, for instance in aerosol from fireworks.

I repeat my question (to Marish) 1. why he needs the conc of the ionic form and 2. whether this applies to their presence in the aerosol or in the analytic solution

In addition

Fully forgot to mention magnesium is also present in a significant amount in seasalt and actually we use(d) it as its tracer.

Harry, thanks for your very valuable information about the aerosols.

Respected Harry Sir,

I want to use the mass concentrations of these ions as input to receptor models for the source apportionment of aerosols and it applies to their presence in aerosols.also for better understanding of aerosols formation mechanism. Additionally Indian aerosols are mostly alkaline in nature.

In case Indian aerosol is alkaline I presume the calcium and magnesium are present as the carbonates. However these are not very soluble species so why are you then interested in the ionic species of these elements for source apportionment. In that case the source aerosol must be classified in the same way. So do you have the source profiles and are these assessed according to compounds?