Atomic Absorption Spectrometry
Equipment:
Solaar M6 Dual Zeeman spectrometer (ThermoScientific) with continuum source (QuadLine) and Zeeman background correction system.
Method:
Atomic absorption spectrometry (AAS) is applicable for the quantitative determination of most elements (all metals, metalloids and some nonmetals) in a wide variety of samples (biological, clinical, food, environmental, geological). Two types of atomization have been commonly used for AAS. The flame is widely used at the part per million (µg/mL) level, whereas the graphite furnace (GF) as the atomizer is used when a limited sample volume is available. In many cases the GFAAS allows the quantitative determination of elements at the part per billion (ng/mL) level. AAS is a spectroanalytical method involving the absorption of optical radiation by free atoms in the gaseous state. The transfer of the energy of a photon to an atom promotes a valence electron in the atom from the ground to the excited state. Absorption only occurs if the energy of the photon is identical to the difference in energy between the ground and the excited state of the atom.
When only the analyte atomic species are present in the sample, the amount of light absorbed will depend only on the concentration of the analyte element in the light path. However, in biological samples materials other than the analyte, derived from the sample matrix and the atomisation system itself, may also be present in the light path leading to background absorption. Therefore, several methods of background correction (QuadLine, Zeeman) have to be applied to eliminate these interferences.
Provided Services:
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Sample preparation using microwave digestion (digestion of tissues, analyte element extraction) or ultra sonic extraction (cell disruption and sample homogenization).
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Quantitative determination of the following elements:
Fe, Cu, Se, Zn, Al, Pb, Hg, Gd, others
Sample preparation:
Samples:
Cells, tissue (animal or human bioptic material), blood, serum, urine, aqueous solutions.
Sampling material:
Contamination of biological materials is of considerable concern since the trace metals are typically in the ng/g level. As minimum precautions, a laminar flow clean air bench, plastic sampling devices, and containers that are non-wettable (PTFE preferred) should be employed. In addition the samples are maintained at 4°C during transport and at -20°C for storage. Whenever possible, plastics should be used for sample collection, storage, preparation, and measurement.
GFAAS is the preferred technique for the determination of trace elements in body fluids. A digestion of the sample is mostly not required. An important advantage of GFAAS is the low sample requirement (a volume of 20 µl to 500 µl is adequate in most cases).
Generally, prior to analysis tissue samples must be digested using acids of high purity (ultra pure).
For analysis of tissue samples two main problems exist. The first problem is the contamination from the instruments used (Al, Cr, Ni, Co, Mn, Cu, Zn, Fe). The second is that organs and tissues are inhomogeneous and since only small tissue samples can be obtained from biopsy, chance often plays a major role during sampling.
Quality control:
We are using certified reference materials for calibration and internal quality control.
Estimated turnaround times: ten business days for single sample submission.
Fees for AAS:
For further details and price, please contact us via “e-mail”
Sample submission form. Download "here".