Test method for spectral bandwidth of AA-1800 atomic absorption spectrophotometer - Master's thesis - Dissertation

Test method for spectral bandwidth of AA-1800 atomic absorption spectrophotometer

Key words: atomic absorption spectrophotometer; spectral bandwidth; US instrumentation ; AA-1800 International has long clearly used the "line profile method" to test the spectral bandwidth. The specific method is as follows: using a line spectrum lamp as a light source (such as a low-pressure mercury lamp or a hollow cathode lamp, but no other spectral line is required within ±20 nm from the test wavelength), and the ordinate of the test spectrum is set as the luminous intensity of the lamp. The abscissa is set to the wavelength. In the case of static (non-ignition), near the characteristic line of the light source (such as 253.7 nm of low-pressure mercury lamp), the atomic absorption spectrophotometer is scanned for wavelength (if a low-pressure mercury lamp is used as the light source, the instrument scans The initial wavelength can be set to 260 to 245 nm); the width at the height of 0.51 at the center wavelength (253. 7 nm) on the scanned spectrum is the spectral bandwidth (SBW) of the atomic absorption spectrophotometer. At present, many people often confuse the spectral bandwidth with the resolution, and use resolution to discuss the resolution of the spectral instrument. In fact, the concept, representation method and test method of resolution have been clearly defined internationally: resolution means that the ability of the spectrometer to separate two adjacent lines on the spectrum requires the spectral bandwidth. The spectral bandwidth refers to the number of spectra per unit length on the spectrum of the exit pupil of the monochromator, which is a physical quantity proportional to the slit width of the spectroscopic instrument.