Lidstrom:UV-2401PC UV-Vis recording spectrophotometer
Back to Protocols
About the UV-2401 PC spectrophotometer
- Shimadzu = manufacturer
- The cuvette position in the back is for the reference cell.
- Wavelength range : 190nm - 1lOOnm (Effective measuring range is 190-900nm)
- Spectral band width (slit width): 6 steps in 0.1,0.2,0.5, 1,2, 5
- Resolution: O.1 nm
- Display of wavelength: 0. 1nm increments
- Setting of wavelength: The start wavelength and end wavelength in scanning can be set in increments of 1 nm. With the Goto WL command, wavelength can be set in increments of O.1nm
- Wavelength accuracy: + 0.3nm (at slit width of 0.2nm). Automatic wavelength calibration is possible.
- Wavelength repeatabihty: plus or minus O.1 nm
- Wavelength scanning speed :
- Switching of the light sources: The light sources are switched automatically in conjunction with wave-length scanning. The wavelength at which the light sources are switched is selectable in the range of 282nm to 393nm in 0. 1 nm increments.
- Stray light:
- Photometric system:
- Photometric range: Absorbance: - 4 - 5 Abs, Transmittance: 0 - 999.9%T
- Recording range: Absorbance: - 9.999 - 9.999 Abs (0.001 Abs of the full scale in maximum expansion), Transmittance: - 999.9 - 999.9%T (0.1% of the full scale in maximum expansion)
Manual page 3: The light source is turned on by the personal computer under specific conditions, as follows:
- When both START and END wavelengths are within the range from 190nm to the switching wavelength, only the D2 lamp will be turned on.
- When both the START and END wavelengths are within the range from the switching wavelength to 900nm, only the WI lamp will be turned on.
- When one wavelength falls below the light source switching wavelength and one above, both D2 and WI lamps will be turned on.
- In the UV-24OlPC, the positions of the light sources are adjusted automatically, ensuring that maximum intensity is obtained from the detector every time the power switch is turned on.
- All the optical elements except light source are sealed from the atmosphere by the windows W, to keep them dust-free. This is one of the features of the UV-2401PC. The slit width is selected
in 6 steps; 0.1, 0.2,0.5, 1, 2,5.
- In normal measurement, a slit width of 2nm is considered appropriate.
- The monochromator is composed of Sl (entrance slit), M2 (mirror), G (grating), M3 (mirror) and S2 (exit slit). The mounting is of the Czemy-Turner type, characteristically providing little aberration.* The Shimadzu-designed blazed holographic grating with 1600 lines/mm provides high optical energy with minimal stray light.
- The images of the exit slit S2 are focused at the cell position in the sample compartment.
- Figure 3-5 shows the relationship between the position of cell and light beam. The cross section of the light beam on the cell is about lmm wide and 12mm high when the slit width is 2nm.
- When a micro cell of narrow width below 2mm is used, it is recommended that the optional cell holder with mask (P/N 204-06896) or the optional super micro cell holder (P/N 206-14334) can be used. In addition, a black masked cell is preferable for decreasing the influence of the scattered radiation.
- The photometer works to compute the ratio of sample signal to reference signal to obtain the transmittance (T%), to perform baseline correction, logarithmic conversion (into Abs.) and smoothing.
Checking wavelength accuraccy (semi-annually)
Wavelength accuracy is checked using the two characteristic wavelength peaks of deuterium E light, at 486.0nm and 656. If the wavelengths of the characteristic peaks do not fall within the specified ranges, contact your service representative. The procedure is as follows:
- Select “Spectrum” from the Acquire Mode menu.
- Select “Parameters” from the Configure menu. Set the parameters as follows:
- Measuring Mode : Energy
- Recording Range : 0 (Low)-100 (High)
- Wavelength Range : 660 (Start)-650 (End)
- Scan Speed : Medium
- Slit Width : 0.2
- Sampling Interval : Auto
- Select the “Energy” push button at the bottom of the Spectrum Parameters dialog box to bring up the Energy Condition Parameters dialog box. Set the parameters as follows:
- Lamp : D2 (Deuterium)
- Detector : PM (photomultiplier)
- PM Gain : 2
- Select the “OK” push button to return to the Spectrum Parameters dialog box, and select the “OK” push button to return to the main scree
- When the photometer setup waiting period ends, select the Start push button to plot the spectrum on the screen graph. When the spectrum has been plotted, a file name and comment may be entered in the File Name dialog box which will appear.
- Select “Peak Pick” from the Manipulate menu. When the channel selection dialog box appears, select the channel corresponding to the wavelength check spectrum and select “OK”. The graph will be redrawn with the characteristic peak indicated, and the Peak Pick
scrollable window which appears will indicate the wavelength of the peak. The peak wave-length should fall in the range between 655.&m and 656.4nm for UV-2401/25OlPC.
- Perform the same procedure again for the other characteristic peak of D2 light using:
- Recording Range : 0 (Low) - 10 (High)
- Wavelength Range : 490 (Start) - 480 (End)
- In this case, the peak wavelength should fall in the range between 485.7nm and 486.3nm for UV-2401/25OlPC.
- "point pick" = a way to pick time points (??)
- Cell Blank:
- When Cell Blank is clicked on the Photometer Button bar, the spectrophotometer takes a reading and subtracts this reading from all subsequent readings during data acquisition. The purpose of the cell blank operation is to eliminate the effect of the cuvette from the results. The cell blank reading remains valid until another Cell Blank or an Auto Zero is performed