UV Of Sodium Aminosalicylate Biology Essay

UV Of Sodium Aminosalicylate Biology analyze special(prenominal) absorbance of the atomic number 11 aminosalicylate erect be determined by victimization the Beer-Lambert law equation with the presence of the time treasure of niggardness of the sodium aminosalicylate and the absorbance set which can be obtained by UV spectrophotometry. The parsimony of dark dissolvents can also be determined by getting the absorbance determine with the calibration chart, rank(a) monastic order and comparative method.IntroductionUV spectrophotometry is a technique which is based on measuring the absorption of near-UV or circumpolar radiation by bulwarkecules. 1 It acts by where the electrons in the bonds within the molecule endure excited to reach up to a higher quantum state and in the process to absorb some of the energy passing through the solution. The much loosely the electrons are been held within the bonds of the molecules, the longer will the wavelength of the radiation (lo wer the energy) been absorbed. 2 radiation sickness in this wavelength region causes the characteristics of the molecular structure of the molecule to be determined. 1As there is a broad absorption bands imputable to different vibrational and rotational energy levels, UV spectrophotometry is use mainly for quantitative purposes rather a than identification.3 Spectrophotometer works by where the experiment of the solution is inserted into the spectrometer for the UV/ visible(a) washy to pass through the take in to get the observe of absorbance/transmittance. The value of the absorbance indicates the amount of light being absorbed by the sample. The measurement of light absorption of molecules can be governed by Beer-Lambert law equation, A= e.c.l. With the presence of the absorbance value (A), concentration of the sample (c) and the pathlength of the cell (l), the molar absorptivitiy (e) can consequently be determined.Concentration of an unknown solution can also be determined by measuring its absorbance development the UV spectrophotometry at the selected wavelength. The tendency of the concentration of the unknown can be determined by victimization three methods, which are by employ the Beer-Lambert graph, comparative method and absolute method.In this experiment, sodium aminosalicylate will be use as the sample as it is a good absorber of ultraviolet light which allows it to be hands down to be analysed utilize spectrophotometry. The purpose of this experiment is to find the detail absorbance of the sodium aminosalicylate solution by using different concentrations of it and also to determine the concentration of the unknown solutions by using calibration graph of Beer-Lambert, comparative method and absolute method.Experimental(a) Absorption Spectrum of Sodium Aminosalicylate in 0.1M NaOHThe spectrum of a 1-cm socio-economic class of 0.001% solution of sodium aminosalicylate in 0.1M NaOH over the wavelength range 235 to 325nm was been scanned and examined. The wavelengths (max) and the absorbance values at these wavelengths of the two maxima was then been measured from the spectrum. Approximate particular(prenominal) absorbance i.e. the absorbance of a 1-cm level of a 1% solution, A(1%,1cm) was then been calculated at each of these maxima using the Beer-Lambert equation A=A(1%,1cm).c.lWhere A= AbsorbanceA(1%,1cm) = Specific absorbance of a 1 cm point of a 1% solutionc = Concentration (%)l = path length (cm)(b) Beers Law, Specific Absorbance and Molar Absorptivity50mL volumes of 0.0002, 0.0004, 0.0006 and 0.008 % solutions of sodium aminosalicylate in 0.1M NaOH from the 0.0010 % stock solution had been prepared. One of the max from (a) had been selected and the wavelength was set to the selected value. The solvent (0.1M NaOH) was been fixed in both cells and the absorbance study of the single beam spectrophotometer was been set to zero. The absorbance was been study a few nm each side of the selected wavelength usin g the 0.0010 % and been record. The tonic max from the table of absorbance values that had been enter was been selected and the spectrophotometer was been set to that wavelength. The absorbance of a 1-cm layer of each of the five solutions of sodium aminosalicylate that had been prepared earlier were been recorded and reiterate readings were been obtained. A graph of absorbance against concentration had been plotted and the particularized absorbance had been determined using the gradient of the graph. The molar absorptivity of the sodium aminosalicylate in 0.1M NaOH at the selected uttermost was been calculated.(c) Determination of Concentrations(i) Calibration GraphThe absorbance of a 1-cm layer of unsung 1 was been determined. vague 1 was then been diluted so that its absorbance is in the mid(prenominal) range of the graph of absorbance against concentration. The graph was then been used to determine the concentration of the diluted solution and hence the concentration of enigmatical 1 was been calculated.(ii) authoritative MethodThe absorbance of a 1-cm layer of stranger 2 was been recorded. The concentration of Unknown 2 was been calculated using the A (1%.1cm) value which had been determined previously.(iii) comparative degree MethodThe wavelength was set to the second max which had been determined in (a). The absorbance of a 1-cm layer of the 0.0010 % and a 1-cm layer of Unknown 2 was been recorded. The concentration of Unknown 2, C2, using the relationship below,=Results(a)Wavelength / nmAbsorbance read2640.6303000.430Wavelengths (max) = 264nm and 300nmConcentration) = 0.001 %At 264nm,Specific Absorbance === 630At 300nm,Specific Absorbance === 430(b)max which been selected from (a) = 264nmWavelength / nmAbsorbance adaptation2590.5842600.5882610.5882620.5822630.5732640.5592650.546Table of Absorbance determineNew max selected from table of absorbance = 261nmConcentration of sodium aminosalicylate solution / % startle Absorbance ReadingSecond Absorbance ReadingAverage Absorbance Reading0.0010.6080.6060.6070.00080.4770.4820.4800.00060.3600.3640.3620.00040.2430.2430.2430.00020.1190.1230.121Specific Absorbance (Gradient) == 606.06From the graph of absorbance reading of 0.46,Concentration of Sodium Aminosalicylate = 0.00076 %RMM of sodium aminosalicylate = 211.150.00076 % = 0.00076 g/100mL= 0.0076 g/1000mL= 0.000036 mol/1000mL= 0.000036MBy using the Beer Lambert equation, A= e.c.l.,e === 12777.78Molar absorptivity (e) of sodium aminosalicylate in 0.1M NaOH at the selected maximum = 12777.78(c) (i) pillowcase of Solution commencement Absorbance ReadingSecond Absorbance ReadingAverage Absorbance ReadingUnknown 11.1871.1881.188Diluted Unknown 1 (Unknown 1 + 0.1M NaOH)0.2860.2870.287Concentration of Diluted Unknown 1 Solution from the graph = 0.00048 %Using the formula C1V1 = C2V2 ,(0.00048) (100) = (C2) (25)C2 (Concentration of Unknown 1) = 0.00192 %(ii)Type of SolutionFirst Absorbance ReadingSecond Absorbance ReadingAverage A bsorbance ReadingUnknown 20.5250.5250.525Using Beer-Lambert equation, A=A(1%,1cm).c.lA(1%,1cm) = 606.06l = 1.00Concentration of Unknown 2 (c) == 0.000866 %(iii)Wavelength (max) selected from (a) = 300nmType of SolutionFirst Absorbance ReadingSecond Absorbance ReadingAverage Absorbance Reading0.0010 % sodium aminosalicylate0.3370.3360.337Unknown 20.3000.3000.300=C2 (Concentration of Unknown 2) = 0.000890 % countersignFrom the experiment (a), we can see that the absorbance reading go downs with the increase of the wavelength where 0.630 absorbance value had been recorded at 264nm wavelength and 0.430 absorbance at 300nm wavelength. When wavelength increases, the amount of energy of the molecules of sodium aminosaliylate will decrease as well. Therefore, the amount of light that will be absorbed by the sodium aminosalicylate will decrease which guideing in the decrease in the value of the absorbance. By using the Beer-Lambert law equation, we can know that the specific absorbance of the sample decreases with the decrease of the absorbance value with a fixed concentration of sodium aminosalicylate and pathlength of the cell.In experiment (b), new max had been selected from the table of absorbance which is 261nm because it had the highest absorbance reading among all values which had been obtained. Repeated readings of absorbance had been recorded when measuring the absorbance values of each of the different concentrations of sodium aminosalicylate. This is to prevent getting an error in the measurement of the absorbance reading in the experiment. When plotting the graph of average absorbance against concentration of sodium aminosalicylate, a blood linear line was obtained. This shows that the value of absorbance increases with the increase of the concentration of sodium aminosalicylate in the experiment. The value of specific absorbance that had been obtained from the gradient of the graph of average absorbance against concentration of sodium aminosalicylate is 606.06. The value is quite typical which is in the range of 20-1,000. However, the value of the molar absorptivity of the sodium aminosalicylate obtained from the graph is 12777.78 which is more than the typical values ranging from 1,000-100,000. This may be payable to some errors produced during the experiment.In experiment (c)(i), the concentration of Unknown 1 obtained from the spectrographic analysis and calibrating graph are almost the same. However, the concentration of Unknown 1 obtained through the calibrating graph is slightly higher than that of the one obtained from spectroscopy. This might be due to some errors in calibrating the graph. Error in the graph will result in getting an incorrect absorbance reading which will be used to calculate the concentration of the unknown solution. However, several measurements can be recorded to minimize the errors.In experiment (c)(ii) and (iii), the results showed that the concentration of Unknown 2 obtained using absolute method is almost the same with the value of concentration obtained using comparative method. Absolute method can be carried if the value of specific absorbance is known with the presence of the value of absorbance. It works exactly based on the Beer-Lambert law equation and is a preferred method in BP. If the specific absorbance of the solution is not known, then comparative method is preferably to be used as it only needs the absorbance reading of the standard solution and the unknown solution.This is a preferred method in USP and works the outmatch if the standard and sample concentrations are close.3 As the specific absorbance of sodium aminosalicylate used in (c)(ii) is obtained from experiment (b), there might be some errors in the value of the concentration of Unknown 2 if errors had occurred when calibrating the graph in (b) which resulting in the value of specific absorbance to be not perfect. Compared to comparative method, only the absorbance reading of the standard and sample solutions obtained from the spectroscopy are required in order to calculate the concentration of Unknown 2. Therefore, in this case the concentration of Unknown 2 using absolute method is not as accurate as the one obtained by using comparative method in this experiment.ConclusionUV spectrophotometry is an universal technique where it can find the value of specific absorbance of a sample using the Beer-Lambert equation with the presence of the other 3 factors value and also to identify the concentration of an unknown both through methods of calibration, absolute and comparative.