Cu (II) acetate is coloured in aqueous media. I am planning for solvent extraction test experiment using Cu (II) acetate. I am thinking of doing a calibration curve with the Cu (II) acetate. After which, I will remove the Cu (II) with an extractant, measure the amounts of cu (II) left in aqueous phase and then determine the distribution constant.
This salt is coloured, could this experiment (both calibration and measurements after extraction) be done without the use of standard complexing agents for color development?
Hello Kaana, The complexing agents are added to enhance the sensitivity. You may construct a curve based on the colour of copper but the absorption spectrum of copper lies at very long wavelengths (somewhere around 650 nm onwards). You will have have very low sensitivity with this short cut method you are thinking of. One can easily do complexometric titrations of copper depending on the amounts of copper with EDTA. You can consult, Vogel's Inorganic Quantitative Analysis book.
If you would insist, you can scan your calibrants (of different concentrations) from 300 nm - 800 nm to see the sensitivity of your solution, even without an addition of a complexing agent. Then you can select the specific wavelength that gives you: (1) good absorbance (sensivity) (2) good linearity of standard curve [concentration vs absorbance] (3) acceptable linear dynamic range. As Farooq said, maybe copper ions alone will have low absorbance values. But you can still try and see. Cheers!
Yes. If the solutions you are working with are colored at your working concentrations then you will be able to do this. As Ms. Nisola points out, you'll need to determine the optimum wavelength for the determination, but you can certainly take advantage of the visible coloration.
Yes, it is possible. You just take water (Colourless solution) as a blank or refrence solution and first measure the wavelength of fixed conc of Cu(II) acetate solution and select the Lambada max. (Maximum Wavelength. Then after by taking Lambada Max. measure the absorbance of each colouerd Cu(II)acetate solution. It is possibel without any complexing ligand....!!
I agree with all the answers before. If you just need the absorption wavelength of Cu(OAc)2, you may use water as a reference. If you can get any good response (especially in the visible region since you have colourful sample) then you can play on the concentration for calibration curve and move forward. If not working then you do not have a choice than to go for standard complexing agents. Regards
It is possible. First, Do the Blank with water only (Millipore / double distilled water), Secondly, do the calibration with lower concentration of Cu (II) acetate in water.
Similarly, do for your organic solvent (alone, with extractant and after extraction with copper) as well and cross check the value, what you obtained from aqueous phase observation.
In both cases, collect the wavelength of fixed conc of Cu(II) acetate solution and select the Lambada max and run your sample at that lambda max without complexing agent.
I think, it is possible. But we keep in our mind, we need complexing agents for a a selective reaction. The selectivity of your method is based on your ligand. So, the direct determiantions can be performed in diluted matrix medium. If your real samples contain a lot of interfering species, it will be harder.
All your contributions have been useful to my studies. thanks. Kaana Asemave
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