I ran a series of very detailed tests on my spectrometer this week, against already established data (references are provided at the bottom of page.) on fluorescein in a buffer of 0.1M NaHCO3 (sodium bi-carbonate-lab quality.) My goal was to test the data acquisition accuracy of the Plab version 2.5 spectrometer.
conclusions, 2 data points stand out and they were sample 1 and sample 7, I examined these two samples because they had the highest degree of absorption, I'll discuss sample's 5 and 12 later. sample 7 conformed to previous studies conducted by the University of Berkeley Ca, Department of Chemistry and Molecular and Cell Biology, sample FT3.
Sample 1 was close to within 3nm (error margin of 9.4%) sample 7's error margin falls within 4.5% of predicted excitation and emission wavelengths.
By contrast samples 5 and 12 having much lower concentrations (0.5mL,) show a significant drop in the inner filter effect, and fell even closer to with specified wavelengths for fluorescein in this particular buffer solution. sample#5-@ 534nm and sample#12-@ 528nm, with sample#5 at a plus 17nm and sample#12 at a plus 11nm.
So sample#5 has a margin of error @ 3.4% +- and sample#12 @ 2.2% +-. an assumption I could make at this point is at least with a concentration of 0.5mL of fluorescein in a buffer of NaHCO3 at 0.1M, can be used as a good calibration indicator for the overall efficiency of the Plab version 2.5 spectrometer kit.
With careful construction and a little modifications in hardware stability, I think it can be said thru this data, that an overall error margin for this piece of equipment can be at around avg. of +- 4.875 percent.
- http://www.pnas.org/content/92/10/4347.long - Department of Chemistry and Molecular and Cell Biology, University of California, Berkeley, CA (my calculations are based in part on sample FT3 0.5mL/fluorescein in NaHCO3 pH of 9.0, from this series of tests.) (my accuracy was within +-3.5% of sample FT3 of this study.)
- http://www.leica-microsystems.com/science-lab/fluorescent-dyes/ http://www.ecol.xyz/webcams-products/2-0megapixel-usb-web-camera-pro514612.html