Hplc Exam Questions And Answers Pdf links:
[GET] Hplc Exam Questions And Answers Pdf | free!
Posted on 8-Apr-2021
Answer : In size exclusion chromatography the separation does not involve chemical interactions between eluting molecules and stationary phase. The separation takes place on the basis of molecular size with larger molecules eluting first and small...
[ VIEW ANSWER ] [ Find Similar ]
[DOWNLOAD] Hplc Exam Questions And Answers Pdf
Posted on 21-May-2021
The reason for its predominant use is that it gives specific response to a particular compound or class of compounds. Most of the organic compounds absorb at specific wavelengths covered in the available wavelength range of the detector. Answer : A...
[ VIEW ANSWER ] [ Find Similar ]
Chapter 18: Multiple Choice Questions
Posted on 1-Apr-2021
Analytes discussed consist of both those considered undesirable substances, contaminants, additives, and those related to nutritional quality. All analytes are currently assayed in our laboratories. Keywords: food and feed analysis, liquid chromatography, challenges, nutritional analysis, additives, contaminants 1. Introduction Food and feed analysis are paramount to assess both nutritional quality and safety of commodities. Interconnectivity of food sources [ 1 , 2 ] and new processing techniques [ 3 ] make for a more diverse and complex food supply.
[ VIEW ANSWER ] [ Find Similar ]
Answers To Questions About Analytical Method Validation, Verification, And Transfer
Posted on 15-May-2021
Legal thresholds have been stipulated that establish acceptable levels for individual chemical additives, residues, and contaminants in products [ 4 , 5 ]. Feed is a paramount target for analysis since it situates at the start of the food chain and poor feed quality can affect the yield on food-producing animals [ 6 ]. Understanding the complexities of food safety is the goal of approaches such as One Health [ 7 ], Farm-to-Fork [ 6 ], or MyToolbox [ 8 ]. Furthermore, feed contaminants carryover downstream can reach products such as meat, eggs, and milk see for example the transference of aflatoxin M1 from aflatoxin B1-contaminated feed.
[ VIEW ANSWER ] [ Find Similar ]
Quiz: Liquid Chromatography
Posted on 21-Mar-2021
Ingredients either destined for food or feed production e. Other regulations require food and feed labeling to list ingredients relating to the nutritional content [ 9 , 10 ]. All stakeholders involved in the food and feed chain must be able to assess product quality and safety. Hence, it is imperative to rely on techniques that meet several analytical performance parameters. More and more, food and feed analysis methods are based on LC liquid-chromatography [ 11 , 12 ], which has proven to be an optimal technology for screening, detection, and quantification of a vast variety of analytes see Table 1. The reason behind this is related to the molecular affinity between the analyte and also: i. Within the LC approach itself, several alternatives are available for a researcher to resolve a specific task at hand. Each analyte presents its own unique trials. Additives Relevance in Feed and Food Quality Acidulants Used in beverage, food, and feed production, are part of the primary metabolism, are often produced by fermentation.
[ VIEW ANSWER ] [ Find Similar ]
Chapter 11: Multiple Choice Questions
Posted on 13-Apr-2021
Acidic additives serve as buffers to regulate acidity, antioxidants, preservatives, flavor enhancers, and sequestrants. Related to beneficial effects on animal health and growth performance as feed additives. Acetic acid, lactic acid, and citric acid [ 13 ]. Antioxidants Lipid and protein oxidation can impact meat quality, nutrition, safety, and organoleptic properties. Antioxidants are added during animal production and meat processing to enhance the nutritional and health benefits of meat and minimize the formation of carcinogens for the chemical safety of cooked and processed meats [ 14 , 15 ].
[ VIEW ANSWER ] [ Find Similar ]
Hplc Related Questions And Answers
Posted on 15-Apr-2021
They can also be used to extend food [ 16 ] and feed [ 17 ] shelf life. Flavors and fragrances Widely used in food, beverage, feed, cosmetic, detergent, chemical and pharmaceutical formulations [ 19 ]. Alcohols, methyl ketones, 2,3-butanedione, lactone, butanoic acid, esters, isovaleric acid, pyrazines, geosmin, vanillin, benzaldehyde, terpenes. Sweeteners Non-nutritive sweeteners have become an essential part of daily life and are in increasing demand as it is used in a wide variety of dietary and medicinal products [ 20 ].
[ VIEW ANSWER ] [ Find Similar ]
Pharma Quality Assurance ( QA ) Interview Questions And Answers
Posted on 17-May-2021
They play a role in the reduction of table sugar [ 21 ]. In the case of artificial sweeteners, their use is controversial as they have associated with health risks [ 20 , 22 ] and water pollution [ 23 ]; currently, the use of natural sweeteners is supported as an alternative [ 24 ]. Sweetened products must be subject to verification to ensure the presence of the sweetener.
[ VIEW ANSWER ] [ Find Similar ]
E-PolyLearning
Posted on 4-Mar-2021
Furthermore, sweeteners are regulated food additives [ 25 ] unless recognized as safe [ 26 , 27 ]. Approved as food additives: saccharin, aspartame, acesulfame potassium, sucralose, neotame, advantame. Natural Components Relevance in Feed and Food Quality Inorganic ions Essential in both raw and processed products, related to food nutritional quality, preservation, technological processing, and safety [ 32 ]. Sulfites, sulfates, phosphate, polyphosphate, nitrate and nitrite, N-nitroso compounds, cyanide, bromide, bromate, chloride, chlorite, fluoride, iodide. Lipids and fatty acids Major constituents of foods and feeds, of dietary importance as a significant source of energy. Provide essential fat-soluble nutrients. Are prone to peroxidation. Part of biological membranes. Biogenic amines Nitrogen-based toxic compounds, mainly formed through decarboxylation of amino acids. Relevant for quality and safety of diverse foods such as dairy products [ 38 ], fermented goods [ 39 ] including wines [ 40 ], fishery commodities [ 41 ].
[ VIEW ANSWER ] [ Find Similar ]
Analytical Chemistry Interview Questions
Posted on 28-Apr-2021
Putrescine, histamine, cadaverine. Amino acids Part of a protein-containing diet, and as supplemented individual products. Amino acids are used in medical parenteral nutrition and dietary supplements [ 42 ]. The main fermentative amino acids for animal nutrition are L-lysine, L-threonine, and L-tryptophan. Carbohydrates The most abundant feed energy in diets for some species of animals [ 43 , 44 ].
[ VIEW ANSWER ] [ Find Similar ]
HPLC Interview Questions & Answers
Posted on 17-Mar-2021
Glucose is the primary energy source for fetal growth, and lactose is crucial for the development of human and animal infants alike. Vitamins Complex unrelated compounds present in minute amounts in natural foodstuffs. Essential to normal metabolism; their deficiency causes disease. Alkaloids Alkaloids are natural compounds with a characteristic cyclic structure and a nitrogen atom [ 46 ].
[ VIEW ANSWER ] [ Find Similar ]
Lab 2: High Performance Liquid Chromatography
Posted on 18-Mar-2021
Alkaloid-containing plants are an essential part of the regular diet, present as natural constituents of several food products [ 46 ]. The most common use for alkaloid-containing plants is as stimulants increased concentrations of these compounds can be attained within the food chain as a result of food processing, as food contaminants or as food flavorings [ 46 ].
[ VIEW ANSWER ] [ Find Similar ]
300+ TOP HPLC Objective Questions And Answers
Posted on 28-Mar-2021
Octopamine, synephrine, tyramine, N-methyl-tyramine, hordenine in bitter orange products [ 47 ], morphine, codeine, thebaine, papaverine, and noscapine in poppy straw [ 48 ], caffeine and trigonelline in coffee [ 49 ], indole and oxindole alkaloids in Uncaria sp. Residues and Contaminants Relevance in Feed and Food Quality Chemotherapeutics and antiparasitic drugs Antibiotics are extensively utilized in productive animals with therapeutic, prophylactic, metaphylactic, growth promoting, and food effectiveness enhancing ends. These practices that have been reflected in veterinary residues in products for human consumption meat, eggs, and milk and is also related to directly with allergies and antimicrobial resistance.
[ VIEW ANSWER ] [ Find Similar ]
Previous Year Question Papers Answer Solution Last 10 Years Entrance Exam Paper Free Download 2021
Posted on 6-May-2021
Tetracyclines [ 56 ]. Mycotoxins Mycotoxins are practically ubiquitous contaminants, classified as teratogenic, carcinogenic and immunosuppressive, and that affects a great variety of grains, fruits and seeds, as well as eggs, dairy products, compounds feeds, and other feed ingredients [ 57 ]. Aflatoxins [ 58 ]. Pesticides Used for crop protection and to treat infestations in livestock. Their poor use results in contamination of the environment and the food itself, impacting human health. Residues usually found in vegetables, fruits, honey, fish, eggs, milk, and meat, serving as potential sources of contamination to consumers [ 59 , 60 , 61 ]. Atrazine, glyphosate, aminomethylphosphonic acid, phenoxy herbicides. Open in a separate window To successfully analyze or isolate a compound, a researcher is faced with several questions: What is the problem to solve, the objective or purpose for the analysis?
[ VIEW ANSWER ] [ Find Similar ]
Liquid Chromatography Questions & Answers
Posted on 19-Apr-2021
Is the required data qualitative or quantitative? Are there two or multiple compounds to be separated? What are the physicochemical characteristics of the target s? What matrix was the analyte recovered from and which interferences are expected? What is the amount of analyte expected to be recovered? What equipment is accessible in the laboratory? Considering the above, a suitable column Table 2 and detection system must be selected Table 3. Sample preparation can aid to solve some of these issues, especially those regarding interferences and sensitivity but cannot solve issues with poor detector choice.
[ VIEW ANSWER ] [ Find Similar ]
Biochemistry - HPLC
Posted on 26-May-2021
Column efficiency is measured in terms of number of plates which is A. For a typical adsorbent such as silica gel, the most popular pore diameters are A. Which of the following statements is true for a refractive index detector in HPLC? It is more sensitive than a UV detector B. It can only be used for isocratic elutions C. It does not respond to many solutes D. Dwell volume is defined as A. Void volume refers to the A. Greater sensitivity and reusable columns B. Ideal for ionic species and large molecules C. Sample recovery D. All of the above Answer: D Which can be used as a mobile phase in HPLC applications? Any compound with solubility in liquid B. Any compound with limited solubility in liquid C. Any compound with non-solubility in liquid D. Any of the above Answer: A.
[ VIEW ANSWER ] [ Find Similar ]
HPLC - Biochemistry Questions And Answers
Posted on 27-Mar-2021
Set up six methods. One for each of the 5 isocratic runs and one for the gradient run. Each run will use the same sample which should be vial slot 1. Each method should be different for each run. Look through the method with your TA and check that all the parameters are correct. Save the method once you are done. Confirm that you have enough of the paraben mixture in the sample vial and that the sample vial is in vial slot 1.
[ VIEW ANSWER ] [ Find Similar ]
Pharma Quality Assurance ( QA ) Interview Questions And Answers - Pharma Job Alert
Posted on 17-Mar-2021
You can print the reports after each run or after all runs are complete. Before moving on, confirm that you have peaks for each of your runs. If you notice any issues with your data, talk with your TA. They can drink it in many types of beverages, eat it in different types of food, and even take it in pill form. Reverse phase HPLC can be used to determine the amount of caffeine in these items. In this experiment, you will be determining the amount of caffeine in coffee, tea, and a soft drink. If the runs are performed with the same isocratic parameters, retention time can be used as a qualitative measure and peak area or peak height can be used as a quantitative measure of caffeine in a sample. In order to determine the concentration of caffeine in these samples, a calibration curve must be put together using a set of standard solutions comparing either the peak height or peak area to the known concentration of the solution.
[ VIEW ANSWER ] [ Find Similar ]
Please Enable Cookies
Posted on 3-May-2021
Accurately weigh out The caffeine can be found on the shelf near the weigh station area. Transfer the caffeine into a clean mL volumetric flask. The stock solution will have a final concentration of 0. Carry out a series of dilutions to obtain standard solutions of 0. Shake each of the mixtures to ensure adequate mixing. Filter the solutions using the provided filter. Do not do this until you are ready to run your samples. The filter and syringe can be reused if the solutions are filtered from low concentration to high concentration. The syringes can be found in the plastic drawers near the door of the lab. Filter approximately 1 mL and dispose of it into a waste beaker to wash the filter. Filter the solution into the appropriate vial. Figure 2. The HPLC can also use plastic vials that look quite similar. Image is taken from www. The beverages can be found in the refrigerator in the lab. Prepare the Coffee Sample. Filter the sample using the provided filter.
[ VIEW ANSWER ] [ Find Similar ]
Liquid Chromatography Questions & Answers - Inst Tools
Posted on 3-May-2021
Confirm with your TA that your data looks appropriate before disposing of any solutions. You can dispose of the small vials for this experiment once you have collected all of your data. If you have already performed Lab 6, then dispose of your samples. Treatment of Data 1. Before completing the lab, confirm that you have peaks for each of your runs. Create a calibration curve using the caffeine standard peak height or area versus the concentration.
[ VIEW ANSWER ] [ Find Similar ]
Multiple Choices On Hplc
Posted on 15-Apr-2021
This will open and HPLC offline window. Go to the CHE file and find your data folder and select it. Double click the first standard run in the sequence window. Repeat steps g and h for each of the remaining standard solutions. The Calibration Table and the Calibration Curve can be viewed in the bottom of the window. Confirm that all the points are there. How many compounds are observed in the paraben mixture? Identify each peak on the gradient chromatogram. Compare the results from the isocratic runs to the results from the gradient run.
[ VIEW ANSWER ] [ Find Similar ]
GK Quiz On Chemistry: PH Scale
Posted on 5-Mar-2021
What advantages does the gradient elution offer? What disadvantages does the gradient elution have compared to the isocratic elution? Plot the results of the retention time of the last component longest retention time in isocratic runs versus percent Methanol for the series of isocratic runs. Do you obtain a linear plot? Questions for Part 3: Analysis of Caffeine in Beverages 1. Describe whether you used peak height, peak area, or both to estimate the concentration. Discuss the advantages to each method.
[ VIEW ANSWER ] [ Find Similar ]
GK Questions & Answers On Chemistry: PH Scale
Posted on 28-May-2021
Make sure you take into account the dilutions you made when preparing the samples. Discuss the errors potentially made during this experiment. Discuss how retention times depends on methanol and the pH of the mobile phase. What factors contribute to the choice of mobile phase composition and pH in the present analysis. If you have already performed Lab 6 — Capillary Electrophoresis, did you get the same concentrations as you calculated in the CE experiment? If the answers are different, discuss possible explanations. Int J Mol Sci. Exposure determinants of phthalates, parabens, bisphenol A and triclosan in Swedish mothers and their children. Environ Int. Principles of Instrumental Analysis Seventh ed. Boston, MA: Cengage Learning.
[ VIEW ANSWER ] [ Find Similar ]
Medical Interview Questions Pdf Blog: 26 Top GAS CHROMATOGRAPHY Questions And Answers Pdf
Posted on 5-May-2021
Test your knowledge in chromatography! Here you can test your level of knowledge in the field of HPLC theory. If you only want a basic understanding of the principles of chromatography you should look at the Novice section. If you use HPLC regularly you need to know the terminology and concepts that are used in chromatography.
[ VIEW ANSWER ] [ Find Similar ]
Chromatography Interview Questions & Answers
Posted on 12-May-2021
Furthermore, you also need to have a basic understanding of how different expeimental parameters affect the separation. It is also important to have a good understanding of the equipment. In the HPLC user section you can test your level of knowledge. If you are responsible for the HPLC work in a laboratory or work with development of HPLC methods, you need to be thoroughly familiar with basic chromatographic concepts and their physico-chemical interpretation. You also need to know and understand how to affect the separation by changing the experimental parameters. Before you do the test you may find it worthwhile to read more about reversed phase chronatography at hplccourse. The test HPLC developer is made for you. Chromatographic research and advanced method development requires a basic understanding of many areas within physical chemistry and chemical engineering. You need to have a good knowledge about e.
[ VIEW ANSWER ] [ Find Similar ]
Analytical Method Validation Questions And Answers
Posted on 12-Apr-2021
Thermodynamics, kinetics and fluid dynamics concepts. Intermolecular forces, properties of solutions etc. In the "HPLC scientist" section you will find a test of your knowledge at this level.
[ VIEW ANSWER ] [ Find Similar ]
Chromatography Multiple Choice Exam Questions
Posted on 15-Mar-2021
As for SS in HPLC, it also becomes extremely difficult to produce, in-house, bur-free, perfect cuts especially when using the narrower IDs less than 0. Question Since that is the case, you can estimate any adjustment from an existing method for injection volume. If you are converting to a different size ID with packing material and length remaining the same , just multiply your current volume by the ratio of the radii squared to determine the correct volume for your new method. Your new volume should be about 8. Answer : In this scenario, the sample is initially concentrated onto the head of the column and moves through the column in a tight band. Keep in mind that your sample components must be soluble in mobile phase as well, in order for this to work. This will help you identify or confirm the source of pressure. If the column itself is found to be the source of difficulty, please follow the column regeneration steps given on our LC Column Cleaning Recommendations page.
[ VIEW ANSWER ] [ Find Similar ]
Liquid Chromatography Analysis Of Common Nutritional Components, In Feed And Food
Posted on 6-Apr-2021
To help avoid future occurrences, Restek highly recommends the use of guard columns to protect your reversed phase and normal phase analytical LC columns from both frit blockage and column contamination. This area is referred to as the interstitial space. You can estimate void volume by multiplying the total column volume pi x radius2 x length by a factor that estimates the typical packing efficiency for a particular column type. Void volume is more commonly estimated experimentally by injecting a standard containing an analyte that is known to have no, or negligible, retention on that particular column phase. A good example of this for reversed-phase HPLC is uracil. One should be aware that this estimation is also subject to extra column dead volume for the specific instrument that is being used, so it may vary slightly.
[ VIEW ANSWER ] [ Find Similar ]
No comments:
Post a Comment