Instrumental Analysis
Mephedrone molecular structure
Nephyrone molecular structure
There are several structural differences between the three chemical substances that make adrenalin distinguishable from both Mephedrone and Nephyrone. The adrenalin molecular structure has a more stable structure more than both Mephedrone and Nephyrone. The adrenalin structure has an extra OH molecule that makes it distinguishable from the Mephedrone and Nephyrone. Several analytical tests can be used to determine this difference.
There are various chromatographic techniques that can be used to test the purity of the adrenalin tablet. The first method is paper chromatography. This chromatographic method is used to analyze chemicals that have different color compositions. In chemical analysis, paper chromatography is effective in that it is easy and effective to see. To test the adrenalin tablet for Mephedrone or Nephyrone, chromatography could be used if the colors of the substances are different. Chromatography of substances is effective because colored substances are more soluble in solvents more than they are likely to bond to paper so in the test they travel further on the paper. If the color of the adrenalin tablet is different from the Mephedrone or Nephyrone their solubility will be different. If the counterfeit adrenalin drug leaves three spot on the paper it proves that there are other substances in the adrenalin.
The second chromatographic method is gas chromatography. This method is common and efficient when analyzing components that can be turned to gas without changing their molecular integrity or decomposing them. In the case of the three compounds adrenalin, Mephedrone and Nephyrone, gas chromatography is effective in that it can be used to vaporized and separated to determine the quantity of each element. To separate the elements that are in the adrenalin tablet, the tablet is diluted in a suitable solvent and put in a sample port where it is turned into gas. The gas samples of adrenalin, Mephedrone and Nephyrone are then carried by an inactive gas, which goes through liquid coated silica. The materials that are not very soluble will be responsible for a faster result than the ones that are more soluble. This will enable the detection of the impurity in the adrenalin tablet.
In gas chromatography, there are various instruments that are used in the process. First, there is the sample injection. This is where the solution containing the adrenal tablet is first introduced. The sample port is often heated so that the solution is vaporized at injection to speed up the process. The sample port temperature is set above the lowest melting point of all the substances in the solution.
The second component in the gas chromatography is the carrier gas. This inert gas is important in this process because it delivers the vapor to the silica and it does not react with the detectors that will detect the different components of the solution. There is a column oven in the gas chromatograph equipment. This is responsible for regulating the temperature in the equipment so that the experiment is exact. The column oven ensures that the temperature needed to melt and vaporize the chemical elements is adequate.
The next part of the equipment is the open tubular columns and the packed tubular columns, which are responsible for delivering the gas to the detection systems. The detection systems are used to detect the amount of individual components that were in the solution before vaporization. They are located at the end of the gas chromatography equipment.
The third method of chromatography is the GC-MS. This is when the gas chromatography is coupled with mass spectrometry. This method could be used to separate the impurities from the adrenalin tablet and know their quantity. For a mixture like the one between adrenalin, Mephedrone and Nephyrone, GC-MS is a good method to use because it is used to separate complex mixtures using sensitivity and high resolve.
There are three steps that are involved in this process of detection and quantification. The first step is the injection process. In this stage, whether the adrenalin tablet is in solid or liquid form it needs to be vaporized. There are several injection techniques that can be used to extract the various substances from their original form.
The second stage is the separation. This takes place in the capillary column, which is supported by a liquid or a solid. An inactive gas is introduced in this stage to carry the vapor to the detectors. The first signs of separation are seen in this part because their vapors move in different velocities in the columns as they head to the detectors.
The final stage is the detector stage. In this stage, there are detectors that can be used to detect the separated components. In this stage, the mass spectrometer uses high sensitivity to determine the difference in molecular structure of the components. In the mass spectrometer, the particular molecules of the components can be bombarded individually since the compound is in gas form. Since the ionization is different for every compound, it is therefore possible to identify individual components using a mass analyzer.
For the GC-MS to be effective, the gas chromatography must be concentrated on more keenly. If the GC part does not separate the compounds, completely the substances going into the mass spectrometer are impure and therefore the analysis will be a failure. In addition, there is possibility of inaccuracy in the mass spectrometer if the amount of spectra to be analyzed exceeds the amount out memory the mass analyzer can accommodate.
The other method of chromatography is the HLPC. This is almost similar to the GC and GC-MS. The pressure that forces the compounds through the columns is more compared to GC and GC-MS, which makes the process of separation faster. This high pressure also makes the process of separation much more effective because the molecular particles are subjected to much more pressure. The detection mechanisms in this method of columnar chromatography is automated which makes detection accurate and efficient.
There are two types of the HPLC. These are the normal phase and the reverse phase HPLC. For the normal phase HPLC, the column is coated with silica and the carrier gas is inert. Since the silica in the column is ionized, the components of the compound that are ionized will stick to the sides of the columns. This in turn will lead to separation of the compounds.
For the reverse HPLC, the silica is not polarized but there is presence of hydrocarbon chains. The other difference is that the solvent used in this procedure is polarized. This will make the ionic components in the solvent move along the columns while the nonionic components stick to the hydrocarbons hence separating the components.
There are several stages involved with the HLPC process. The first one is injection; in HLPC, the process is automated. This is necessary due to the high amount of pressure that is involved. The time the compound takes in the solvent in the columns is different from in the GC and in the GC-MS. This is due to a variety of factors including, the component composition of the compound, the pressure in the column, and the temperature in the column. For the HLPC, the detection of the components is used by the individual absorption of UV light. In our case, the rate of absorption in Adrenalin, Mephedrone and Nephyrone is different therefore and this will make it possible to determine their difference in the counterfeit adrenalin tablet.
The other methods of detection and quantification of impurities in the adrenaline tablet is LC-MS. This method differs from HLPC on the basis that it has a mass spectrometer. The equipment uses reverse chromatography to separate the individual components of the solvent. After the HLPC process, the mass detector scans the individual molecules that constituted the compound therefore producing a full spectrum of ions based on their mass. The reason the HLPC process is involved is that most compounds are almost similar in terms of molecular structure. Adrenalin, Mephedrone and Nephyrone have just a few moieties to differentiating them. The HLPC procedure helps further separate these compounds that could have the same molecular mass. This is because the mass detector cannot detect the difference in their structure if their masses are the same. The other reason why the HLPC process is involved is that the chemicals introduced in the columns may compromise the molecular integrity of the components. The HLPC process helps purify the components before they enter the mass detection process.
The HLPC used in liquid chromatography must be the reverse form. This is because if the normal chromatography is used, the presence of salts in the solvent would clog the columns and compromise the system. The presence of the mass spectroscopy is because it ensures the purity of the end product. In the process of detecting, separating, and quantifying adrenalin from the impurities in the tablet, mass spectroscopy would ensure that the individual components were in their purest form.
The last method of detecting and quantifying individual components of the adrenalin tablet is mass spectroscopy. Mass spectroscopy is a technique that is used to separate the atomic masses of components that form a compound. The spectrometer is responsible for three main processes; ionization, analysis and detection. In the ionization process, a small amount of the compound is vaporized so that the ions can be released. The second part is the separation of the ions. They are separated by their mass and charge. The final part is the detection part. In this segment, the ions are detected, grouped, and tallied.
This mass spectrometer has a vacuum at the detection stage. This vacuum chamber is used to store the ions because they are short-lived and could be reactive with air. The main part of the mass spectrometer is the ion source. The collision that follows after the gases and volatile liquids are released causes electrons to be released. During this bombardment, the heavier ions push the lighter ions away resulting in separation of the ions.
A mass spectrum is displayed in a graph. The graph shows individual mass and charge of all the components of the volatile liquid or gas. The mass spectrometer distinguishes even the atomic masses that are slightly different. This enables the even the isotopes to be separated. There is a slight difference in the composition of adrenalin, Mephedrone and Nephyrone; this would make the mass spectrometer suitable to detecting the presence of impurities in the adrenaline tablet and the quantity of each component.
There are fragmentation patterns that appear during the analysis of a mass spectrometer. The presence of a fragmentation assists in identification of the molecular structure of the components. This only applies to some molecules; this is because some molecules react with the air around them and their integrity is compromised. Fortunately, adrenalin, Mephedrone and Nephyrone are organic and are therefore give spectra that include a molecular ion and are therefore easy to analyze.
For atoms with molecular structures that are almost similar, mass spectrometers with high resolutions are used. These spectrometers are used to categorize the molecules that have the same nominal mass. This further increases the accuracy in which the components are detected and quantified.
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