What is the best LOD that can be typically expected from UV-VIS absorbance spectroscopy ( mg/L,(µg/L, ng/L)
What is the best LOD that can be typically expected from fluorescence spectroscopy ( mg/L,(µg/L, ng/L)
instrumental analysis question
LOD that can be typically expected from UV-VIS absorbance spectroscopy is µg/L.
LOD that can be typically expected from fluorescence spectroscopy in ng/L.
What is the best LOD that can be typically expected from UV-VIS absorbance spectroscopy ( mg/L,(µ...
In comparing fluorescence spectroscopy to UV‑Vis absorption spectroscopy, which of the statements is true? Fluorescence measurements do not suffer deviations from linearity like absorbance measurements do. Fluorescence measurements are more precise and less noisy because only the intensity of the emitted light is measured. Fluorescence instruments are less expensive than absorption measurements. Fluorescence measurements have better detection limits because at low concentrations a low intensity emission signal is being measured against a low intensity background signal.
Explain what is the purpose of using UV-vis spectroscopy for this particular experiment. What is the maximum wavelength in nm that the TA used to collect the absorbance value of Fe(SCN)2+?
5
A calibration curve used in UV/VIS spectroscopy plots concentration on the y-axis and absorbance on the x-axis. O A) True OB) False Question 5 (2 points) A working standard is prepared by taking 38.00 mL of a 500.0 ppm stock solution and diluting it tos a final volume of 650.0 mL. Calculate the ppm concentration of the working solution. Provide your answer to two places after the decimal and without units. Your Answer: Answer Submit Out 2afactione ad
1. What is the parameter that makes the absorbance of a sample inside a UV-VIS cell to change as a function of wavelength? Why? 2. What are the benefits of using the wavelength of maximum intensity (max) for the analysis?
A plant extract was analyzed by UV-vis spectroscopy and the following data were obtained: What is the molar absorptivity of the chromophore? Concentration (M) Absorbance 5 X 10-5 0.051 10 X 10-5 0.098 15 X 10-5 0.157 Hint: You need to look at the units of molar absorptivity. Rise over run?
Part 2. UV-Visible Spectroscopy Cut2 concentration Absorbance (mol/L) 0.0010 0.053 0.0025 0.128 0.0050 0.251 0.0075 0.378 0.0100 0.510 Diluted unknown, Trial 1 0.079 For your lab notebook: C. Sketch how you could make each of the the 5 standards for Part 2 from a 0.100 mol/L Cu2+ stock solution, 1.25 mol/L NH3 solution, and Dl water. The procedure is referenced in step 2b. Assume you would use 10-mL volumetric flasks to make the solutions. d. Sketch also how you would...
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Suppose you obtained the following data from two standard solutions of known concentrations using a UV-Vis spectroscope: Analysis # Conc. (mg/L) 8.00 20.00 Absorbance (at 255 nm) 0.160 0.390 What is the concentration (in mg/L) of an unknown solution with an absorbance of 0.200 at 255 nm 10 points)? The unknown solution contains the same analyte as the standard solution does (Assume a path length of 1cm). 10. You prepared a stock solution by dissolving a...
Consider the following balanced reaction. What mass (in g) ofCO2 can be formed from 288 mg of O2? Assumethat there is excess C3H7SH present. C3H7SH(l) + 6 O2(g) → 3CO2(g) + SO2(g) + 4 H2O (g)
Beer’s Law Objective : We will explore an application of absorption spectroscopy using calibration curves and Beer’s Law. Use the “LAB : HOW TO…” link from the class website if you need help with how to use balance, Bunsen burner… and such. Introduction: You may write this information in your lab notebook for your own reference. It can’t be cut and pasted. Different solutions have different spectral properties. In this portion of the experiment those properties will be utilized to...
What is the net yield of ATP (or equivalents) that can be
expected from this?
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Question 2 1 pts Assume that one molecule of phosphoenolpyruvate (PEP) is catabolized under aerobic conditions. What is the net yield of ATP (or equivalents) that can be expected from this? Assume that re-oxidation of NADH via the electron transport chain yields the equivalent of 2.5 ATP, and that re-oxidation of FADH2 yields...