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What is hybrid micellar liquid chromatography primarily used for in the study?
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To detect commonly used pesticides in vegetables. |
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MLC is a mode of HPLC in which solutions of surfactants at a concentration above their critical micellar concentration are employed as mobile phases. Three different equilibria exist for a solute in MLC. It can distribute between the aqueous mobile phase and the micellar mobile pseudophase, between the stationary phase and the micellar pseudophase, and between stationary and aqueous mobile phases. However, for highly hydrophobic compounds, a direct-transfer mechanism from the micellar to the stationary phase has been proposed. Solute retention is related to the concentration of micellized surfactant in the mobile phase through solute–micelle association constants or distribution coefficients that can be calculated as a direct application of MLC techniques.
The great number of interactions that are possible in MLC separations, such as electrostatic, hydrophobic and esteric, and the modification of the stationary phase by adsorption of monomeric surfactants, make these systems more complicated than conventional RP-HPLC. However, the fact that the amount of the surfactant adsorbed remains constant after equilibrium between mobile and stationary phases allows MLC techniques to achieve rapid micellar and organic modifier gradients.
The control of separation selectivity in MLC can be performed through a great number of parameters; these include the nature and concentration of the surfactant in the mobile phase, the presence of additives as organic modifiers and salts, and the pH. The fact that the addition of an organic modifier to micellar mobile phases can increase selectivity and reduce analysis time has increased the use of hybrid micellar mobile phases, which also preclude the efficiency loss inherent to MLC as compared to conventional RP-HPLC.
Other applications that can be cited in MLC techniques are directly derived from the special characteristics of micellar solutions. The sensitivity of the detection can be enhanced and biological fluids can be directly injected into the chromatographic systems because of the solubilization of the protein by some surfactants. Finally, the fact that micelles can be considered as chemical models for biomembranes has enabled the application of MLC to hydrophobicity estimation of organic compounds. |
Micellar Liquid Chromatography |
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| 2 |
Which pesticide was found most commonly in the vegetable samples?
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Chlorpyrifos |
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he aim of present study was to assess pesticide residues in vegetables in the Hyderabad region of Pakistan. The concentrations of six pesticides were determined by gas chromatography coupled with mass selective detector (GC-MSD) in locally produced vegetables purchased from wholesale markets. A total of 200 samples of eight vegetables viz |
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| 3 |
What percentage of the vegetable samples tested were found to contain no detectable pesticides?
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20% |
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| 4 |
Which of the following is NOT a reason for the use of hybrid micellar liquid chromatography (HMLC)?
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It is easy to handle. |
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| 5 |
What was the primary methodological change in the HMLC technique used in the study?
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Use of highly toxic solvents. |
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| 6 |
According to the study, why might vegetable growers prefer other pesticides over Imidacloprid (ICP)?
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ICP is more expensive. |
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| 7 |
What is the major benefit of using ICP as a pesticide, according to the study?
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It is the only pesticide available. |
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| 8 |
What aspect of the pesticide detection method was focused on during the method validation phase?
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Verifying its ability to handle very large vegetable samples. |
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| 9 |
Considering the environmental impacts discussed, why is the HMLC method considered 'green'?
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It is funded by environmental organizations. |
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| 10 |
What is the importance of the photodiode array detector in the HMLC technique used in the study?
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It increases the cost of the analysis. |
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| 11 |
What is hyperthermia commonly used to treat?
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Chronic pain |
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| 12 |
Which method is used to apply heat directly to a tumor in local hyperthermia?
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Ice packs |
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| 13 |
What is the primary benefit of using hyperthermia in cancer treatment?
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It is a standalone treatment. |
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| 14 |
Hyperthermia is often used in combination with which of the following treatments?
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Antibiotics |
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| 15 |
What is the main challenge of using hyperthermia in cancer treatment?
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It is very expensive. |
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| 16 |
Which type of hyperthermia involves heating a larger region or the whole body?
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Regional hyperthermia |
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In regional hyperthermia, doctors apply heat to large areas of the body, such as a cavity, organ, or limb. Techniques used in regional hyperthermia include deep tissue techniques, regional perfusion, and continuous hyperthermic peritoneal perfusion. |
Hyperthermia to Treat Cancer |
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| 17 |
What type of hyperthermia uses applicators inserted into or near a body cavity to deliver heat?
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Regional hyperthermia |
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In regional hyperthermia, doctors apply heat to large areas of the body, such as a cavity, organ, or limb. Techniques used in regional hyperthermia include deep tissue techniques, regional perfusion, and continuous hyperthermic peritoneal perfusion. |
Hyperthermia to Treat Cancer |
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| 18 |
What is a significant potential side effect of whole-body hyperthermia?
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Systemic stress affecting major organs |
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Burns and Tissue Damage: Raising the body's temperature to high levels can lead to burns or tissue damage if not carefully monitored. Dehydration: Hyperthermia can cause excessive sweating, leading to dehydration. |
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| 19 |
Considering the physics of heat transfer, why is controlling hyperthermia challenging during treatment?
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Human tissue has varying thermal conductivities which affect heat distribution. |
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Identifying the size of human blood vessel that influences Hyperthermia Treatment. |
The cooling effect of blood flow during hyperthermia treatment |
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| 20 |
Why is hyperthermia considered a beneficial adjunct to radiotherapy and chemotherapy?
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It makes cancer cells more susceptible to other treatments. |
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Hyperthermia is therefore an adjunct to cancer treatment along with radiation therapy and chemotherapy. Normal cells will not suffer any side effects from the treatment. But cancer cells accumulate heat, weakening their cell membranes to make chemotherapy and radiation more effective. |
Hyperthermia - Chiwamitra Cancer Hospital +CMH |
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