5. Atomic Absorption Spectrophotometer












Make:Perkinelmer, USA

Model: AA700, 2006

Specification:

  • Monochromator: Littrow design with motorized drive for automatic wavelength selection and     peaking.
  • Wavelength range : 190 - 900 nm
  • Diffraction grating : 1800 lines/mm blazed at 236 nm and 597 nm
  • Grating area : 64 x 72 mm
  • Reciprocal linear dispersion: 1.6 nm/mm (nominal) Focal length: 267 mm
  • Spectral bandwidths : 0.2, 0.7 and 2.0 nm, dual height; motorized slit drive for automatic slit      selection

    Accessories

  • Monochromator
  • Detector
  • Lamp Assembly

    Description

    Atomic Absorption Spectrophotometer (AAS) is a spectroanalytical instrument for the quantitative determination of chemical elements using the absorption of optical radiation (light) by free atoms in the gaseous state. In analytical chemistry the instrument is used for determining the concentration of a particular element (the analyte) in a sample to be analyzed. AAS can be used to determine over 70 different elements in solution or directly in solid samples.

    Principle

    The technique makes use of absorption spectrometry to assess the concentration of an analyte in a sample. It requires standards with known analyte content to establish the relation between the measured absorbance and the analyte concentration and relies therefore on the Beer-Lambert Law. In short, the electrons of the atoms in the atomizer can be promoted to higher orbitals (excited state) for a short period of time (nanoseconds) by absorbing a defined quantity of energy (radiation of a given wavelength). This amount of energy, i.e., wavelength, is specific to a particular electron transition in a particular element. In general, each wavelength corresponds to only one element, and the width of an absorption line is only of the order of a few picometers (pm), which gives the technique its elemental selectivity. The radiation flux without a sample and with a sample in the atomizer is measured using a detector, and the ratio between the two values (the absorbance) is converted to analyte concentration or mass using the Beer-Lambert.

    Applications

    Determination of following elements in Soil and Tobacco.
  • Copper
  • Zinc
  • Iron
  • Manganese

    User instructions

  • Clearly mention the name of the character for which analysis is required
  • Provide minimum 0.5-1.0 kg leaf or 100-200g powdered tobacco
  • Provide minimum 1Kg soil

    Analysis Charges

    • Rs.500/-+GST per sample for element