Hello Clement! I believe the answer to your question lies within the following three articles:

1) TIAN, Y. H., PEPELNIK, R. and FANGER, H. U.: Multielement Analysis of Archaic Chinese Bronze and Antique Coins by Fast Neutron Activation. J. Radioanal. Nucl. Chem., 1990, 139(1); pp. 43 – 50.

2) JACKSON, K. W. and MAHMOUD, T. M.: Atomic Absorption, Atomic Emission, and Flame Emission Spectrometry. Anal. Chem., 1994, 66(12); pp. 252R – 279R.

3) BELARRA, M. A., RESANO, M. and CASTILLO, J. R.: Discrimination of the Causes of Imprecision in the Direct Determination of Metals in Organic Solid Samples by Electrothermal Atomization Atomic Absorption Spectrometry. J. Anal. At. Spectrom., 1998, 13(5); pp. 489 – 494.

Are you using an electrodeless discharge lamp (EDL)? Be aware that high levels of Si in solution will interfere with Cd readings. In the past, I have had success using the 228.8 nm wavelength with acetylene (fuel) and air (oxidant) in a lean fuel mixture using a standard neubulizer and flow spoiler. You can improve sensitivity with a high sensitivity neubulizer or a impact bead. The problem with the 228.8 nm wavelength is that you only have a linear range of 2 mg/L so it is essential to dilute samples above 2 mg/L. If your concentrations are significantly high, you can use the 326.1 nm wavelength with acetylene (fuel) and nitrous oxide (oxidant) in a lean fuel mixture (and a smaller slit at 0.2 nm); however, you lose sensitivity at the low end but gain a much wider linear range. It is a balancing act with AAS which is avoided by using ICP.

Hi Clement,

Actually, Cd can be analysed by several techniques including AAS (Graphite furnace and Flame) and ICP (AES, MS, etc). The decision on what technique to choose depends on several factors including the levels of concentration you are working on, matrices of the samples, what techniqueis available for you as an user, etc. Nowadays, there are AAS instruments (ie. High Resolution Continuum Source AAS) capable to produce elemental data with lower limits of detection comparable to those obtained by ICP-OES. I think that if you are able to control and demonstrate good quality of the results by AAS that achieve the aims of your reseearch, you don't have to worry about using this technique for cadmium measurements.

Hi Clement. If we are speaking about modern equipments, Adriana explained very well. I believe the problem is much more created by the extraction used than due to the instrumental technique. At this moment, I am comparing Zr results from XRF(total) and ICPMS before tetracid digestion (nearly total) and the correlation is very good. Be aware that the kind of digestion you use, will release only a part of the metal content or "all" the metal content. It depends on the intensity of the chemical attack.

If you are planning to use or looking for another determination method, I include to you this lecture. http://mx.search.yahoo.com/r/_ylt=A0oGkmih3JNQtC4AMB_D8Qt.;_ylu=X3oDMTE2cmZlbzlhBHNlYwNzcgRwb3MDMTgEY29sbwNzazEEdnRpZANWSVBNWDAzXzc0/SIG=16mu0fnk6/EXP=1351896353/**http%3a//irmm.jrc.ec.europa.eu/EURLs/EURL_heavy_metals/legislation/Documents/Official%2520methods%2520for%2520the%2520determination%2520of%2520heavy%2520metals%2520in%2520feed%2520and%2520food.pdf

"Nowadays, there are AAS instruments (ie. High Resolution Continuum Source AAS) capable to produce elemental data with lower limits of detection comparable to those obtained by ICP-OES."

Even without this special light source, Graphite Furnace (Electrothermal Atomization) AAS is giving better detection limit for Cd than ICP-OES.

Anyway, this is my observation...

I don't believe that is true. I've always made my Cd analysis using FAAS or GFAAS and the results were always accurate as it can be seen by checking the accuracy values from the simultaneous analysis of Cd concentration in reference standard materials from BCR. That is not a general problem at leat for plant, sediments and animal tissues.

Hello, there is no problem here. It all depends on concentration and matrix. The only way to be sure what you are doing is to chose a good Certified Reference Material. Problem solved.

Don't believe unless you check it urself. I've always made my Cd analysis using FAAS and the results were always accurate as it can be seen by checking the accuracy values from reference standard materials from CANMET. The problem can be solved if same matrix is used for standards and samples and I recommend filteration to remove silica in acidic media.

I fully agree with Carlos Guitart.

You should take into consideration certain points

- ICP OES: the type of nebulizers;

- For AAS: the atomizer – a flame (F AAS) or a graphite furnace (GF AAS)

As ICP OES is not my field of expertise let’s concentrate on AAS.

Determination of Cd in several matrices using AAS has been described extensively in the literature. In case of F AAS, it depends on the concentration and sometimes maybe a pre-concentration step might be required, but in most case the LODs are comparable with those obtained by ICP OES.

Using conventional GF AAS (i.e., with a line source) and following the STPF concept the results are usually superior to those obtained using ICP OES.

Nowadays using GF combined with HR CS AAS (again it is important to follow the STPF concept) the results can be comparable those obtained using more sophisticated techniques, such as ICP MS.

Last but not least, for both conventional and HR CS GF AAS it should be considered that is the only “technique” that allows the direct analysis of solid samples, which improves the LOD and reduces the risk of contamination and losses.

Therefore, please go on and use AAS for the determination of Cd. I wish you a lot of success.

Maria, thank you for the concept. I want ask you, what is the meaning of the acronim STPF and can you furnish me with some literations.

in my opinion, the first, you must validating the method (such as, linearity, accuracy by CRM, repeatability, LoD and LoQ), the second, you should to know the matrix effect,determination Cd in complex matrix usually using by standard addition calibration.