Dear Jeevan,

Attached is a paper discusses the analysis of Ca ions by spectrophotometry.

In addition there is the abstract of another paper:

Journal of the Brazilian Chemical Society

On-line version ISSN 1678-4790

J. Braz. Chem. Soc. vol.13 no.1 São Paulo Jan./Feb. 2002

http://dx.doi.org/10.1590/S0103-50532002000100012 

Article

 Spectrophotometric Determination of Trace Amounts of Calcium Using the Calcium Complex with Alizarin

Abstract: 

The reaction between calcium and alizarin (ALZ) was investigated for the spectrophotometric determination of trace amounts of calcium. The cationic surfactant, cetyltrimethylammonium bromide (CTAB) was useful to increase the sensitivity. The beta-correction method was applied for the determination of the properties of the Ca-ALZ complex instead of ordinary spectrophotometry. Results showed that the complex formed, expressed as Ca(ALZ)2, has a real molar absorptivity equal to 3.74´103 L mol-1 cm-1 at 630 nm.

 Keywords: beta-correction principle, calcium complex, alizarin, trace calcium

Good luck,

Rafik

If you have access to an instrument for measuring fluorescence, there are several fluorescent dyes that can be used to measure calcium concentration in solution.

https://www.thermofisher.com/us/en/home/references/molecular-probes-the-handbook/tables/summary-of-fluorescent-ca2-indicators-available-from-molecular-probes.html

There are many commercial kits to measure calcium colorimetrically.  Sigma Aldrich has one, but you can find others with a Google search.  Most use o-cresolphthalein as the indicator and require a plate reader or spectrophotometer at 575 nm wavelength.  It is an easy assay to conduct--just one step and time insensitive.  Here's a link to the Sigma kit.

http://www.sigmaaldrich.com/catalog/product/sigma/mak022?lang=en®ion=US

I agree with Adam. For UV spectrometry the Fura dyes are very good, particularly so if your samples are fairly pure. I have had some issues with interference from some biological materials (hemoglobin for example).

You will need to excite at 340 and 380 nm, and collect the emission at 510 nm.

Upper level saturation is around 30-50 uM. So if you expect your values will be higher than that, you will have to dilute.

What is the source of sample?

Mr. Vallepu,

By a classical analytical approach - complexometric titration with EDTA.

Dear Jeevan,

Here is method of volumetric determination of Ca in solution

United States Patent 3,121,613 CALCl UM DETERVHNATION METHOD Donald L. Bittner, 2206 Hayes St, San Francisco, Calif. No Drawing. Filed Apr. 26, 1961, Ser. No. 1tl5,55l 7 Claims. (Cl. 23-23ll) This invention relates to quantitative volumetric analysis for determining calcium in a solution. More particularly, it relates to the direct titration of calcium in the presence of magnesium employing chelometric and colorimetric indicator techniques.

http://www.google.com/patents/US3121613 

Good Luck!

I agree with Adam and Michael that dyes can be a good option. o-cresolphthalein kit from Sigma should work with simple spectrophotometer. Just watch out for interference from Mg2+ and possibly other divalent ions. Phenol Red dye from the media may interfere as well.

Not much difficulty in the determination of ca by visible spectrophotometry. Provided the requirement of analytcial range  and nature of sample matix matters. Ca determination is best possible in alakline medium 

Does anybody know the limit of detection of Ca carbonate by UV Visible spectroscopy? any reference pl.?

It will help

Determining calcium concentrations using a UV spectrophotometer typically involves the use of a colorimetric assay where calcium ions react with a chromogenic complexing agent. Here is a step-by-step guide:

Safety note: Always follow appropriate lab safety protocols when handling chemicals and samples.

With this protocol list, we might find more ways to solve this problem.

Determination of calcium in alumina hydrate, calcined alumina and process liquor

PATENT No.378743

Abstract

The present invention provides a process for the determination of concentration of calcium in a sample; said method comprises the steps of: a) obtaining a sample selected from the group consisting of alumina hydrate, calcined alumina and process liquor; b) subjecting said sample to a treatment selected from the group consisting of alkali digestion, fusion with flux and dilution to obtain a treated sample; c) adjusting the pH of the treated sample followed by adding an amine based masking reagent and an aromatic metal ion indicator to form a Ca (II) complex solution; and d) measuring the absorbance of said solution at a wavelength ?max 600-620 nm using a spectrophotometer in order to determine the concentration of calcium.