I need some help in finding out the concentration of heavy metal using T60 UV spectrophotmeter. But I have not enough idea about it. I am getting confused as someone says that I can measure the absorbance directly using uv spectrophotometer while someone says that I need to add reagents or colorimetric solution to the sample to induce color.If someone knows the procedure please tell me about this.
Dear Aminul,
The UV spectrophotometer is not indicated in heavy metal quantification. It will be very nice and easy if the direct measurement of a sample will give you the real concentration. Anyway there are some applications using reagents and colorimetric methods but theses are different for each metal that you wish to analyze. The problems are the many interference with other elements and compounds from your solution....so I cannot expect quality results. The type o the sample is very important. Some authors authors suggested that you can measure the K, Na, Mg from an aquatics pure solution using selective electrodes..... To be ones with you the best methods are the AAS (Fl and GF) and ICP(MS, OS) but even with these there are problems sometimes if the sample matrix is very complex. These two methods requires sample preparation and digestion with acids (depends on the element). You have a good control, complex analysis and processing of signals with many quality control protocols, tests........
Best wishes,
Stefan
Colorimetric methods are not sensitive or specific and thus - as outlined above- prone to interferences from other components in your sample solution. In determining low levels of heavy metals in many types of samples, other methods like AAS or preferably ICP are to be used.
I agree with suggestions of Dr. Stefan, better use AAS or ICP-MS for heavy metal analysis.
Dear Aminul,
Spectrophotometric analysis of metals is something of the past. It required specific chelators and subsequent extraction, as wel as relatively high metal concentrations. I had some experience almost 50 years ago with this approach, and I was very glad that AAS was introduced.
If you are interested in measuring one or two metals, (graphite furnace) Atomic Absorption Spectrometry is still the method of choice. If you want to measure a larger range of metals, ICP-MS is recommended.
All the best,
Frederik de Wolff
I agree with Dr. Stefan, Dr..Frederik De Wolff , Dr. Anand Kumar and others, it is better to use AAS or ICP-MS for heavy metal analysis. Inductively coupled plasma mass spectrometry (ICP-MS) is a type of mass spectrometry which is capable of detecting metals as well as several non-metals at concentrations as low as one part in 1015 (part per quadrillion, ppq) on non-interfered low-background isotopes. This is achieved by ionizing the sample with inductively coupled plasma and then using a mass spectrometer to separate and quantify those ions. Compared to atomic absorption techniques, ICP-MS has greater speed, precision, and sensitivity. However, compared with other types of mass spectrometry, such as Thermal ionization mass spectrometry (TIMS) and Glow Discharge Mass Spectrometry (GD-MS), ICP-MS may encountered with interferences.. Be vigilant: due to possible applications in nuclear technologies, ICP-MS is a subject for special exporting regulations concern.
Cyanidin as a chromogenic reagent extract from Hibiscus rosasinensis flower is used in favor of chelator. Afterwords calibration equation are established with respect to pure heavy metal ions on cyanidin complex.
Proper pH at first validate the method.
Then full of selective approach unknown sample are pretreated.
Using calibration equation you can predict heavy metal ion concentration with previously established linear reange. ( Matrix effect, interferents , specificity ...followed by ICH validation scheme researcher get in his target answer).
Remaining personal response also good ....for respective instrument.
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