The Flame is the Atomizer in which the sample undergoes desolvation and vaporization at high temperature. This waste is still highly acidic and care should be taken in its handling and disposal.Īn oxidant and a fuel gas are mixed together and lit to create the flame for FAAS. Through an exit tube into a glass container. Excess aspiration liquid is removed by gravity and the waste is collected Larger droplets are stopped byīy baffles or spoilers and flow to waste. At the same time, the combustion gases rushing through the nubilizerĭraws liquid sample into the flow and is introduced into the flame as very fine droplets. The high velocity of the combustion gases cause a negative pressure inside the nebulizer chamber and create a suctionįor an uptake tube by a process of aspiration. With fuel and oxidant for introduction into the flame.The nebulizer uses the combustion flames to atomize and introduce the sample into the light path. The nebulizer sucks up liquid sample at a controlled rate, create a fine aerosol that mixes It gives a constant and intense beam of the specific analytical line or wavelength of the element. This is the Source of the analytical light line for the element which is to be measured. It is imposed with a 10mA current such that when the metal is excited electrically, characteristic spectral line/linesĪre emitted and passed directionally through a glass UV/VIS window of the lamp. The Hollow cathode Lamp is made with an element (metal) as the cathode encased in a bulb with a low pressure inert gas.
The following components make up the AA spectrometer : A computer data system converts this change into an absorbance. The instrument measures the change in intensity. This decrease in intesity of the light is the process of atomic absorption. If that metal is present in the sample, its atoms will absorb some of the light, thus reducing its intensity. The sample of interest is aspirated and atomized into the flame. Metals will absorb ultraviolet light in their elemental form when they are excited by heat, either by flame or graphite furnace.Įach metal has a characteristic wavelength that will be absorbed. In atomic absorption spectrometry, light of a specific wavelength is passed through the atomic vapor of an element of interest, and measurement is made of the decrease in the intensity of light as a result of absorption by atoms in the 'excited' state. Typical concentrations range in the low mg/L (ppm) range. Metals include Fe, Cu, Al, Pb, Ca, Zn, Cd and many more. (l)Solute-volatilization interference occurs when the rate of volatilization of aerosol particles changes due to the lack or presence of a concomitant.Atomic Absorption Instrument SpectrophotometerĪtomic absorption is the determination of the presence and concentrations of metals in liquid samples. (k)The interfering substance provided in excess to avoid spectral interferences is known as a radiation buffer. (j)Chemical interference is defined as a change in absorption properties or an analyte's emission caused by chemical processes such as atomization. (i)The phenomenon of spectral interference is the overlapping of an analyte's absorption line by another interfering species. (h)The absorbing back of emitted radiation by non-excited atoms in the lamp is referred to as self-absorption. (g)Sputtering is the process of forming atomic clouds in a hollow cathode lamp. (f)A hollow cathode tube is a type of glass tube that is frequently used in atomic absorption studies. (e)Pressure broadening is the process by which the collision of absorbing or emitting species with other ions generates a broadening of spectral lines compared to normal ones. (d)Atomization is the process of converting samples to atoms. (c) The ionization suppressor allows for greater electron concentration to be introduced, which improves sensitivity. (b) In Atomic absorption spectroscopy, protective agents are chemicals that generate stable volatile species and overcome interference. (a)Cations that interact with the analyte and remove chemical interferences are referred to as releasing agents.
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