Thanks alot Dr. Boertz for your kind reply.

I will try this and see how it goes.

Best regards

The palladium solution is an universal modifier for GFAAS, I used palladium nitrate 5000 mg/L (10uL for 30 uL of sample for partitioned tubes (Varian)) for e.eg. cadmium, lead, arsenic, selenium determination.

hi Abdullah,

Good comparison of PGM's as modifiers for determination of different elements here

Volynsky, Spectrochim. Acta 59 (2004), 1799

Dear Abdullah,

Best Cd modifier for our biological samples quantified on GFAAS proved to be combination of 9 g/L Pd(NO3)2 and 1 g/L Mg(NO3)2 , Se modifier 0.15 % Pd and 0.1 % Mg(NO3)2

(5 uL of this modifier was then added to 20 uL sample).

If low signal with various MM, maybe it is the digestion method.

Thank you all for your kind answers. It gives me great pleasure to have some help through Researchgate from nice friends like yourself guys (Dr. Niedzielski, Dr. Diets and last but not least Dr. Lazarus). I will try a combination of these modifiers and see which one(s) will give better signal.

Dear Amund, thank you for your kind reply. Selenium analysis will be my next challenge. Currently I am struggling with Cd. I have been using different modifiers suggested by my friends (top) for cadmium analysis such as 10% NaH2Po4, 1% Pd modifier MgNo3 , 1% EDTA, 1% Lanthanum ...etc and I also tried different combinations of them but I was always getting double peaks having same signal (absorbance) even for high range standards. I tried to change the furnace temperatures (drying and pyrolysis steps) but the problem of having double peaks (2 peaks) is still there. I am using a graphite tube from Perkin Elmer with Lvov platform, Part # B3 000641. Could graphite tube be the problem?

selamun aleykum Abdullah,

My methode for Cd in graphite AAS: I use microwave digetion for samples with nitric acid and hydrogen peroxide. And I use 10 ppm palladium for matrix modifier. 20 micro litre sample + 5 micro litre matrix modifier.

My graphite furnace methode for Cd is attached.

if you want to use flame AAS, ıt doesn't need matrix modifier. But Flame AAS detection limit is higer than Graphite AAS.

if you have problem or you want to discuss something, you can write me.

Alekum Alsalam my friend Fikret. I tried your furnace parameters too plus Pd modifier but it is the same problem. I shifted to using flame mode instead of furnace using Pd modifier and up to now, I am getting very acceptable results in the accuracy study.

Ok. Graphite furnace analysis are too difficult. Because lots of thing can changes your results. Flame AAS has enough detection limit for 5mg/L (ppm). İf you don't need results too lower than that (around ppb), flame AAS is useful for you.

have nice work

Analysis of cadmium has some aspects to be taken into account , in order to release cadmium from mineral or organic matrix is necessary to digest the sample , the digestion is performed with the help of nitric acid , or any other oxidizing agent, and application of heat, via wet , microwave , etc. . If the cadmium content of a sample (whether biological or not) is in the range of mg / kg (mg / L or ppm ) can be analyzed by the method of flame , the analytical characteristics for my computer are : wavelength 228.8 nm , slit 0.7 nm; relativo1.0 noise, check solution 1.5 mg / L , this solution should give you 0.2 absorbance units , no need to use matrix modifier , the only interference that can occur is by the presence of silicates .

On the other hand if the cadmium content is in the range of ug / Kg (ug / L or ppb ) , testing of the graphite furnace method , if applied in this case the use of matrix modifiers , and is recommended using NH4H2PO4 and Mg(NO3)2, the solution of sensitivity is 2.0 ug / L and you should give an absorbance of 0.13 .

From our experience , we used magnesium nitrate without phosphate at a concentration of 0.1 %.

The key to getting a good result is the digestion of the sample , and of course an excellent curve calibrations .

Regards from PhD Isidoro Rubio Franchini .

Dr. Fekret, Dr. Franchini, thanks for your kind responses. Dr. Franchini, I am running pure Cd standard diluted with D.I.W. which I guess does not require digestion, in addition to using different matrix modifiers including MgNO3. Yet even with this solution, the experiment hasn't been successful so far because of the double peaks problem. This is why I opted to use flame mode instead of furnace, and so far so good. Thanks again

Dear Colleague, Inorganic ions influence the results of Cadmium determination in AAS by dispersion.

Did you try to extract Cadmium as an organic complex from the aqueous solution using methyl isobutyl keton :

Frank A. Automated wet ashing and multi-metal determination in biological materials by atomic absorption spectrometry. Fresenius Z. Anal.Chem. 1976. 279:101-102.

Iskandar, Petersson L., Frank A. Determination of lead and multi-metal in tissue samples using methyl isobutyl keton extraction and atomic absorption spectrophotometry.

Indon. J. Trop. Agric. Vol. 2(1) 14-19. 1999.

The method works excellent for Cadmium too. Best wishes Adrian

Assalamu'alaikum Abdullah Alghamdi

Frankly, I learn much from your question and answers delivered by many experts.

Hopefully you succes with your AAS measurement.

Warm regards from your brother in Indonesia. :)

Sujarwo

Alekum Alsalam dear brother Sujarwo. yes of course this community here in researchGate is more like colleagues working in the same place.

Thanks for your kind comments with my best regards

Abdullah

Dear Abdullah,

I think you are seeing the effects of using an incorrect matrix modifier. Try running the cadmium without the matrix modification. Also, raise your volatilization temperature (the final temp) 200-300 degrees. I would not ash cadmium higher than 500C - it melts significantly lower than that - but you do need to rapidly volatilize and L'Vov platforms are relatively slow devices.

Thanks alot Dr. Krause for your valuable comments.  Indeed I recently tried to run Cd without modifier solution and the validation results I got were very acceptable.

Best regards