This was the original spectrometer from Plab's spectrometer kit that inspired me to modify its concept and build the DH 4.2 spectrometer, so I kept their original design intact and only put the parts in an enclosure, I thought perhaps this might make a good visual comparison between the original and my modified design.
Measurements between the slit to cmos camera eye are not as important as precise alignment of camera to DVD grating and DVD grating to slit entrance, so with this in mind, the camera is now at 39 deg relative to slit entrance and DVD grating is at same (39 deg) relative to cmos camera eye, for a UV-VIS spectral bandwidth of 343nm - 700nm (this is due to the camera's limitations.)
I have reduced the ruling density of the DVD grating down to 4.7g which equates to 1,351 lines per mm. The slit width is now 0.12mm. Project box dimensions are: 190mm X 109mm X 55mm
Slit width dimensions are: 25mm in length Cmos camera from slit: 88mm Camera angle: 39.5 degrees DVD grating angle: 39 degrees Entrance coupler for slit and cuvette holder: 44mm in Diameter
New Plab v2.5 Upgrade pics below
First plot showing Plab spectra as compared to SpexFluoroMax
Second plot with more detail
As you can see by the data, I am within 9nm [525nm] of the target of 516nm for the spectral data taken by the Oregon Medical Laser center for Fluorescein in Ethanol. The new enclosure has eliminated a lot of stray light that occurs with light entering the slit, according to the University of California Santa Barbara (UCSB) Science Line, an object's color represents the wavelengths of light that the object reflects. For example, white objects reflect all wavelengths of light, red objects reflect red wavelengths, and black objects absorb all wavelengths and reflect none.
Light energy can be converted into heat energy. Because white objects reflect all light, they do not have as much energy to convert to heat as black objects; therefore, light-colored objects are typically cooler than darker objects. To demonstrate heat absorption of various colors, you can place pieces of variously colored construction paper in the sun and record their surface temperatures every few minutes. The dark colors become hotter than the lighter colors. _ref _ http://www.reference.com/science/color-absorbs-heat-b73ca519b983f629?qo=contentSimilarQuestions
Preparation for the Fluorescein sample are straight foward, dissolve 1 gram fluorescein powder in 250ml distilled water and vortex in a magnetic stirrer for 2 hrs or until no particles remain and run solution through a filter to remove remaining micro particles, now you have a 0.1M solution of Fluorescein standard to use.
Fluorescein was tranfered to cuvette via serological pump pipette at 0.1 ml per drop for a total of 0.4ml of fluorescein sample in semi-micro cuvette.