Saturday, May 18, 2019

Inductively Coupled Plasma †Atomic Emission Spectroscopy Essay

The aspiration of this practical was to use an ICP-OES to perform a multi-elemental synopsis of different types of tea leaf leaf. The elements that were analysed in the tea were copper, iron, manganese and magnesium.The render is introduced into the plasma as an aerosol. Argon gas flows through three concentric quartz tubes in the plasma torch. This argon gas transports the sample from the nebulizer, acts as a cooling gas and is in like manner a seminal fluid of electrons and ions for the plasma 1. A magnetic field is created around the plasma torch. The ionisation process is started by the release of the argon gas from a spark produced by a tesla coil 1. During this process the plasma reaches a very high temperature and the sample is atomised.The atoms are then excited to a higher state. Since this is an emission analysis, the analysis is performed as the atoms emit energy and return to a lower energy state or their solid ground state. A spectrometer or monochromator is u sed to select the wavelength that is being analysed. The multi-element detector then gives us a readout that can be understand for each element that is analysed rationalise the benefits and limitations of plasma over a courtly flame used for FES with photometry and AAS. The benefits of using plasma are that the chemical interferences are decreased ascribable to the high temperatures that the plasma reaches and refractory elements can also undergo excitation.There are also galore(postnominal) wavelength for different that can be chosen for analysis so you dont have both elements that have wavelengths that are close to each other as this would interfere with the analysis. A limitation is that apparitional overlap can occur and the preparation of the samples is a very long process compared to that of the flame spectroscopyDataShow the calculations for you multi-element quantity.Instrument Perkin Elmer OES (optima 5300 DV)The preparation of multi-element standard snow0ppm solutio ns of (Cu), (Fe),(Mg) and (Mn ) were given. A working standard solution containing the consummate four elements was prepared in the following way 1 ml, 10 ml and 5 ml of Fe, Mg, and Mn were respectively added in one 100 ml volumetric flask. A solution of Cu was prepared separately (intermediate solution) by placing 1 ml of the 1000ppm Cu solution in a 100 ml volumetric flask and made up to the mark with distilled water, the resulting density was 10ppm. The formula that was used to write in code the volume of the 1000ppm Cu solution needed to prepare 10ppm solution in a 100 ml volumetric flask is C1V1 = C2V2 equation 1Where C1 is the sign concentrationC2 is the final concentrationV1 is the volume of the initial concentrationV2 is the total volume of the initial concentration and the solvent The volume of the barium required was metric as followsC1V1 = C2V21000ppm x V1 = 1ppm x 100mlV1 = 10 ppm x 100 ml1000 ppm= 1 mlThen 1 ml of the 10 ppm Cu solution was placed in the 100 ml vo lumetric flask that contained the other three elements, and made up to the mark with distilled water, this was the working standard solution. victimization equation 1 it is found that the concentrations of the elements in the working standard solution are as follows.Explain why the type of sample preparation carried out was necessary. The Acid digestion was suitable because a complete absent of analyte into the solution in order for the determination step to be introduced in liquid form is highly desirable and this method completely transfers the analyte into solution. This thus means that the digested sample is a complete solution of the analyte and has a complete decomposition of the matrix however with minimal loss or contaminated of the analyte Explain what matrix matching is and what problems may arise if this is not carried out.Matrix matching involves preparing solutions in which the major chemical compositions of the standards, blanks and samples are made identical thereby cancelling out the effect of the sample matrix on the analysis results. speckle matrix matching involves matching the solvents, it also involves matching the concentrations of acids and other major solutes. In case where the standard and sample matrices are quite different or cannot be matched and interference occurs as a result, privileged standards can be used.Comment on the correlation coefficient of your calibration graphs. The correlation coefficient measures the strength in the unidimensional relationship between two variables. A correlation coefficient of 1 would mean a very buckram linear relationship between two variables, which means the points form a perfect straight line. The correlation coefficients for the calibration graphs were very good. The calibration graphs for copper, iron, magnesium, and manganese gave correlation coefficients of 0.991539, 0.991005, 0.999874, and 0.999952 respectively. This shows that the samples were prepared very well and that there is a strong linear relationship between the emission and theconcentrations of the elements. Compare the different elements in the different types of tea. Which tea would you recommend and why? The tea that seems to be most essential for human consumption is the green tea owing to the high content of each and every element present in it. It has high concentration of manganese which is a vital substance in the body as it is an enzyme activator it keeps bones strong and healthy, and also maintains the health of our nerves. References1. Dr L Pillay, Chem 340, Instrumental Analysis, ICP-OES notes 2. http// www.whfoods.com/genpage.php?tname=nutrint& dbod=77(accessed 16/04/2013) 3. http//www.chemplex.com/petrochemical/multielementMetal.aspx(accessed 16/04/2013)

No comments:

Post a Comment

Note: Only a member of this blog may post a comment.