Question

With the aid of a clearly labelled diagram, briefly, but informatively, describe a hollow cathode lamp (HCL) commonly used in atomic adsorption spectroscopy (AAS) (b) What other source is used for AAS instead of HCL?

Answer 1

a) Hollow Cathode lamp CHCD Anode Hollow cathode Quartz or pysen wind or Class shield Noble gas We or Ar at 1-5 toss In atomic absorption speedometers, HCL is used as a spectral line somce. It contains a tungsten anode and a hollow cylindrical cathode made of the element to be determined. These are sealed in a glass tube filled with an inert gas (neon or argon) at low paessuie- Each element has its own unique lamp which must be used for the analysis. There is a glow discharge between the cathode and anode, in which positive gasions are formed, which sputter element atoms of the cathode at xelatively low temperatures. Sputtered metal atoms are excited to impact with the ionized gas. Light of wavelength specific to the element comprising the cathode is emitted when the atom decays from the encited state to the normal state

b) what other source is used for AAs instead of HOL? The other type of lamps are electrodeless discharge lamps that contain the element in a Small quartz tube filled with a noble gas. These lamps are commonly available for Sb, As, Bi, Cd, Cs, Pb, Hg, K, Rb, Sn, te etc. A high frequency field reads to a plasma within the tube, in which the element is excited and emits specific light.