General Lamp Information - PerkinElmer aanalyst 200 User Manual

System Description

General Lamp Information

There are a number of different lamps that can be used with the AAnalyst 200 instrument: the
Lumina Hollow Cathode Lamp (HCL) and the Electrodeless Discharge Lamp (EDL) (coded
and non-coded). The Intensitron Hollow Cathode Lamp (coded and non-coded), when used
with an adapter, will function on the AAnalyst 200 instrument. All three types of lamps can also
be used in the AAnalyst instrument.
The type of primary source lamp required for your instrument depends on the elements to be
determined. Either hollow cathode or electrodeless discharge lamps may be used. Hollow cathode
lamps (HCLs) are excellent for most elements; however, there are a number of "difficult"
elements for which an improved light source is desirable. Electrodeless discharge lamps (EDLs)
are more intense than the HCLs. Most EDLs provide better lamp life, stability and in some cases
better sensitivity.
The 3 types of lamps that can be used in the AAnalyst 200 are listed:
•
the Lumina hollow cathode lamp (HCL)
•
the coded Electrodeless discharge lamp (EDL System II)
•
the coded and non-coded Intensitron hollow cathode lamp (HCL) with adaptors
The basic AAnalyst 200 instrument has a mount for a single lamp. It can, however, be purchased
with an automatic four-lamp turret.
An Explanation: Hollow Cathode Lamps (HCLs)
The specific determination of one element in the presence of others is possible with the use of
special light sources and careful wavelength selection in a spectrometer. A single-element lamp
emits specific wavelengths of light for the element from which the cathode is constructed. There
are single-element lamps for all elements commonly measured by atomic absorption. Hollow
cathode lamps (HCLs) are ideal for determining most elements by atomic absorption
spectroscopy. "
Refer to figure below. The basic components of an HCL are a glass cylinder filled with an inert
gas (argon or neon) at low pressure, an anode, a cathode, and a quartz window with a graded seal
to be used at wavelengths below 230 nanometers (nm), or a UV-transmitting glass window for
lamps to be used at longer wavelengths. The cathode is a hollow cylinder of the metal whose
spectrum is to be produced. Both the anode and cathode are sealed in the glass cylinder. The
quartz graded seal or glass window is fused to the glass cylinder.
Figure 4- 2 The workings of a hollow cathode lamp (HCL).
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