User Manual PEAK INSTRUMENTS INC
3
2.1.3.2. Fluorescence and photochemical reactions, in general, errors
fluorescence spectrophotometry produced negligible fluorescence efficiency is
very small in most cases the color system, and the fluorescence emission is
isotropic, only a small portion along the transmitted light direction into the
detector, the measurement of absorbance is low, resulting in a negative
deviation. Depends on the instrument to measure the impact on the absorption
of fluorescence great extent on the optical absorption cell and detector design.
2.1.3.3. Reflection and scattering, absorption law applies only to homogeneous
medium absorption system, turbid solution so that the measured increase in
absorbance due to scattering, resulting in deviation from Beer's law
2.1.3.4. Non-ideal instrument error caused
2.1.3.5. Beer's law deviation polychromatic contrast, the majority of the
photometer can only get close to monochromatic light with a narrow lumen, in
fact, there is still a polychromatic nature, can lead to deviations from Beer's law.
Deviation depends on the two monochromatic molar absorptivity difference △ ε,
| △ ε | is very small, can be approximated that monochromatic, at low
concentrations, curve remains linear, but larger concentrations, with
concentration increases, AC curve bend more serious, there is Beer's law
applies only to dilute solutions
2.1.3.6. Stray light, stray light entering the detector means is unnecessary
components to be tested at other wavelengths outside the range of the
wavelength spectral bandwidth. The main dispersive element from a prism or
grating spectrometer, a mirror, a lens surface scattering, dust and other inner
walls of monochromator components and diffuse reflection and other scars, the
stray light can cause serious measurement error. The instrument is the smallest
wavelength of energy, usually at a maximum stray light (such as deuterium lamp
220nm, tungsten lamp 340nm)
2.1.3.7. Slit width, the slit width of the spectrum affects not only the purity, but
also affect the absorbance. When quantitative analysis in order to obtain
sufficient measuring signal, the slit should be larger, in the qualitative analysis of
the use of a smaller slit when the entrance slit and the exit slit width equal to the
width of the slit caused minimum error
2.1.3.8. Wavelength scale ruler of error, the wavelength of the gauge that
wavelength accuracy of the instrument, such as a large error or correction, the
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