Optical Sensor Essay

• Secondly, we also used a colorimeter which is extremely accurate when it comes to measuring the percentage light transmission. As it measures the percentage light transmission as a numerical value.

From this graph and chart we can see that the higher the concentration the higher the absorbance, all the different concentrations were tested at the same wavelength (625nm). Also we can determine our unknown substances concentration by using the absorbance we got for it. The red dot on the graph followed by the line towards the horizontal axis indicates that the concentration of fast green was 34% or 5.1x10-3.

The ending result of this experiment confirms that as five test tubes are lined up with the varying level of absorbance, different results in the level of absorbance will appear as well, this is visible in above table. Thus, this is due to the varying amount of water in the solution. The blank sample had a 0.30 in its level of absorbance.

The Beers Law calibration experiment used many concentrations of crystal violet solutions. Each of these solutions were test and analyzed in order to determine the absorbance of each concentration The results were than graphed and produced a slope of 1.00E05 with an intercept of -2.21E-02.

5. The degree of precision was to 3 significant figures obtained with the spectrophotometer. The major source of error in our experiment was not calibrating the spectrophotometer with distilled water.

Sensitivity: The ability for the scale to measure both the response and stimuli without being affected.

Using the reflectance spectrum in these three states, only, does not have high accuracy, as shown in 3, 4 and 5 Tables. However, adding derivative spectrum increases R^2 to a large extent and decreases the relative RMSE. The highest〖 R〗^2, in a 1bit method, relating to the use of the reflectance spectrum code and the derivative code is for 400-1050 nm wavelengths to 2nd order and 500-800nm to 3rd order. In the 2bit case, using the reflectance spectrum and the derivative to 3rd order, in both used wavelength, had better function and the best result for the 3rd state was in the 400-10560nm wavelength to 3rd derivative and 500-800 nm to 2nd order derivative. Deletion of the blue region from the beginning of the spectrum and regions by more than 800nm wavelength were effective in improving the results. Although using 3bit code causes lengthening the disciplinary code, among these three states, by considering the reflectance spectrum and its derivative behavior in more detailed, was more successful than the first two states to manifest the

A spectrophotometer is an instrument which measures the amount of light of a specified wavelength which passes through a medium. This instrument is usually used for the measurement of reflectance of solutions. Light is separate into different wavelengths and is being passed through the sample solution. The sample solution will have its own wavelength and will absorb a certain amount of light. The higher the molecular concentration, the higher the absorbance value.

The absorbance is measured using a Plate reader and a Standard curve is generated. Also, the different types of pipetting techniques are assessed in this Assay.

Analysis mode: The procedure is done to estimate different types of molecules and their individual quantities in the mixture using the help of a detector.

This entry was posted in Research papers and tagged UV Spectroscopy research paper, UV Spectroscopy research proposal on May 19, 2013.

Incorporation of assay controls included setting up a spectrophotomer and running the chart recorder with a full-scale deflection before the start of the assay. The set recorder had a corresponding value of 1 for the change in the absorbance. Therefore, prior testing was done to observe whether a change occurred in the readings. This helped to indicate that the results were valid, as they could have been affected by a fault during the setting up of the spectrophotometer. On the other hand this was considered as one of the controls for the experiment. Nevertheless, a new cuvette had to be used for each assay.

In this experiment, the use of a glass cuvette was used in order to avoid any chemical or environmental interference from the surroundings. Furthermore such glass cuvettes can support large wavelengths during transmission of light beyond 320 nm since this is the excitation wavelength region. Riboflavin is excited at around 370 nm, therefore the wavelength range must be large in order to detect a proper response. Plastic cuvettes are however inadequate as the range of wavelengths supported for transmission of light is very limited (5, Upstone). The geometry of the instrument of the spectrophotofluorometer has a specific angle and position for the excitation source and the detector. The excitation polychromator emits ultra-violet radiation and light to the interested sample and the shape of the polychromator resembles a triangular prism in which the monochromator has been angled at a 90∘ position. The transducer would detect the irradiation excitation beam and transfers it through the emission polychromator. The emitted beam would then travel to the detector to allow for the response signal to appear for the sample on the computer system (416, Skoog). The position of the cuvette is essential as it enables for the consistent readings of the response signals, as any shift in the cuvette position can create variation in results due to the position of lighting and detection of molecular samples hitting at different angles. The process of fluorescence is quite sensitive than absorption due to having lower detection limits because of the fact that it can detect lone molecules in excited states that are irradiated by UV-light unless they come into contact with other molecules within

concentration, record the absorbance readings at a fixed wavelength, and plot the absorbance vs. concentration data. The wavelength of 520 nm was selected for experiment Part

We have timed each of the three experiments for 5 minutes to make sure that our results are correct. Thanks to the program, we got the transmittance and the absorbance, together with the graph portraying our results.