Gas Chromatography and Thin-Layer Chromatography Recitation Worksheet Section Na
ID: 1086686 • Letter: G
Question
Gas Chromatography and Thin-Layer Chromatography Recitation Worksheet Section Name Recitation problems may be collected randomly for a grade. . Four analytical/spectroscopic tools are introduced in C343 lab. For each instrument below, describe the importance of each method: Instrument How are each of these analytical tools important in the analysis of chemicals? Gas chromatograph (GC) Infrared (IR) Spectrometer Nuclear Magnetic Resonance (NMR) Spectrometer Thin-Layer chromatograph 2. (aL- is used to separate volatile components of a mixture. A small amount, in (b) sample to be analyzed is drawn up into a syringe. The syringe needle is placed into a hot injector port of the gas chromatograph, and the sample is injected. The injector is set to a temperature (c)than the components boiling points. So, components of the mixture (d) into the (e) gas, such as GC column. It is within the column that separation of the components takes pl of the inside the injector. A carrier , flows through the injector and pushes the gaseous components of the sample onto the (the mobile phase) and (h)(the stationary phase) within the GC column. After due to differences in the partitioning between mobile and Ideally, components of the components of the mixture move through the GC column, they reach a (i) mixture will reach the detector at G) stationary phases. The detector sends a signal to the chart recorder, which results in a peak on the chart paper. The- of the peak is proportional to the number of molecules generating the signal. The (1) of peaks is to the number of compounds that are in the mixture. 4. During the GC analysis of banana oil product, you observe three peaks: a large peak at 1.3 min (102 cm2) and two peaks past 6 min (74 cm2 and 14 cm2, respectively). Identify the compounds for these peaks. Did you achieve the desired purity of banana oil? If not, estimate the % purity of your collected productExplanation / Answer
As per rules, only the first four questions will be answered.
1. a. Gas Chromatography
Gas chromatorgraphy is used majorly in the quantitative and qualitative analysis of foodstuffs which include the natural products present, food composition, presence of aromatic components and contaminants. Gas chromatography is used for determination of volatile components. Thermally labile or involatile substances can not be detected by the use of GC. GC is also used in the analysis of carbohydrates in food and is particularly used when the concentration of carbohydrates is low in a sample providing high sensitivity and better resolution. Further by associating it with a mass spectrometer, its analytical capability can be further increased and unknown components can be identified very easily. Also incase of GC, the extensive cleaning of samples prior to the analysis is not required which makes it all the more efficient.
b. IR spectrometer
IR spectroscopy is widely used in the identification of organic molecules. An infrared beam is directed at the sample and by measuring the radiation absorbed by the sample, identification of unknown molecules can be done, the most common being the FT-IR (Fourier transform Infrared spectrometer). It is used in the detection of impurities too. Advantage of IR spectrometer is that it can be used for all types of samples be it solid, liquid or gas and is non-destructive.
c. NMR spectrometer
NMR spectroscopy finds a great utility in both analytical and organic chemistry. It is used in determining the composition and purity of samples and in quality control. It allows the structural analysis of complex structures and the identification of thermally labile compounds. It is highly useful in the study of polymer degradation and can analyse the disintegration products at quite an early stage. Advantages of NMR spectrometer is that it can be used for all types of samples be it solid, liquid or gas and does not destroy your sample. So your sample can be used again for other analytical methods. Also with NMR you can work with any sample size from small to large and at a range of temperatures.
d. Thin Layer Chromatography
Thin Layer Chromatography is widely used in forensic sciences in the determination of explosives, drugs etc. It is also used to determine the purity of a compound. It is a very inexpensive, fast and reliable technique. Only a few materials are required for this method that includes a chamber, solvent, watch glass, capillary and a plate. More than one compound can be separated using TLC and the solvents can be changed easily. It is also used to determine the purity of a compound. Identification of compounds can be done just by checking the retention factor literature values.
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.