In an experiment O A. 7.50 O B. 0.775 determine the riboflavin by fluorescence spectrometry, a series of riboflavin standards was analyzed and gave a calibration with a slope of 1000 ppm" and a y intercept of 25. If a sample gave a fluorescence reading of 750, what is the riboflavin concentration (in ppm) of the sample? OC.0.0750 O D.0.725

In an experiment O A. 7.50 O B. 0.775 determine the riboflavin by fluorescence spectrometry, a series of riboflavin standards was analyzed and gave a calibration with a slope of 1000 ppm" and a y intercept of 25. If a sample gave a fluorescence reading of 750, what is the riboflavin concentration (in ppm) of the sample? OC.0.0750 O D.0.725

Macroscale and Microscale Organic Experiments

7th Edition

ISBN:9781305577190

Author:Kenneth L. Williamson, Katherine M. Masters

Publisher:Kenneth L. Williamson, Katherine M. Masters

Chapter14: Ultraviolet Spectroscopy, Refractive Indices, And Qualitative Instrumental Organic Analysis

Section: Chapter Questions

Problem 4Q

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In an experiment to determine the riboflavin by fluorescence spectrometry, a series of riboflavin standards was analyzed and gave a calibration with a slope of 1000 ppm-1 and a y intercept of 25. If a sample gave a fluorescence reading of 750, what is the riboflavin concentration (in ppm) of the sample? A. 0.725 B. 0.775 C. 0.0750 D. 7.50
A sample solution containing quinine was analysed by fluorescence spectroscopy. 5 mL of the sample solution was diluted with 0.1 M HCl to a final volume of 100 mL. The fluorescence of the solution was measured and gave a value of 54. A reference solution containing 0.086 mg/mL of quinine gave a fluorescence reading of 38. A blank solution gave a fluorescence reading of 21. Calculate the quinine content of the sample solution in mg/mL.
The levels of Vitamin B1 in a sample of milk was determined using the Standard Addition method and technique of fluorescence spectroscopy. 18.0 ml of the milk sample was diluted to 20.0 ml using distilled water and then the fluorescence was measured. The resulting signal was 210 units. A spike was made by taking 18.0 ml of the same milk sample, adding 1.0 ml of a 6.0 ppm Vitamin B1 standard solution, and then diluting to 20.0 ml using distilled water. The signal of the spiked milk was 540 units. Calculate the concentration of Vitamin B1 in the original milk sample (in ppm). Report to 3 decimal places.
50 uL of an aqueous sample of double-stranded DNA is dissolved in 950uL of water. This diluted solution has a maximal absorbance of 0.326 at 260 nm. What isthe concentration of the original (more concentrated) DNA sample, expressed in ug/ul? I would like to know the process of this question. And I was wondering as well if the total diluted volume would be 950ul + 50ul = 1000ul
Exactly 5.00 mL aliquots of a solution containing analyte X were transferred into 50.00-mL volumetric flasks and the pH of the solution is adjusted to 9.0. The following volumes of a standard solution containing 2.00 µg/mL of X were then added into each flask and the mixture was diluted to volume: 0.000, 0.500, 1.00, 1.50 and 2.00 mL. The fluorescence of each of these solutions was measured with a fluorometer, and the following values were obtained: 3.26, 4.80, 6.42, 8.02 and 9.56, respectively. ii. Using relevant functions in Excel, derive a least-squares equation for the data, and use the parameters of this equation to find the concentration of the phenobarbital in the unknown solution.
"[FeSCN2+]eq is calculated using the formula: [FeSCN2+]eq = Aeq/Astd x [FeSCN2+]std where Aeq and Astd are the absorbance values for the equilibrium and standard sample respectively." I am confused about what Aeq and Astd mean. We did an experiment where we measured the absorption of this chemical formation and I got around 0.18. Is that one of the values?
From this mass spectroscopy, determine the molecule correspond? Masse molaire (g/mol) Abundance 70000] 60000 50000 40000 30000 20000 10000 m/z--> 0 38 50 Bromo-2,4- dinitrobenzène 75 247 g/mol 107 100 154 KSCN à 50 % 97,18 (d=1,34) (12.703 min) 170 218 246 150 200 250 Bu4NBr 322,37 g/mol 3 03:23 36382 300 350 400 2,4- dinitrophényl thiocyanate 225 g/mol 449473 5833 TITIITT 450 500 550 KBr 119 g/mol
(2) Adenine has a molar absorbance of 4 13.1 M-1cm-1 for 263 nm nucleic acid. What is the molar concentration of an acid solution that shows a permeability of 75% when 2 ml of it is placed in an absorption cell with a thickness of 1 cm?
c. Upon mixing CFP-a-p34 with GFP-a-p34 and 3-p34, the fluorescence of CFP drops from 100,000 to 96,000. When CFP-a-p34 is mixed with GFP-B-p34 in the presence of 0.5M GdnHCl the fluorescence of CFP drops from 100,000 to 63,900. If the Förster radius for the donor/acceptor pair is 50Å, how far apart are the donor and acceptor in each case?
Q1: The concentration of yeast t-RNA in an aqueous solution is 10 M. The absorbance is found to be 0.209 when this solution is placed in a 1.00 cm cuvette and 258 nm radiations are passed through it. a) Calculate the specific absorptivity, including units, of yeast t-RNA. b) What will be the absorbance if the solution is 4 M? c) What will be the absorbance if the path of the original solution is increased to 7.00 cm?
You obtained the following raw data when setting up a Biuret standard curve: Absorbancy 540nm BSA (mg/ml) 0.158 1 0.210 2 0.260 3 0.305 4 0.360 0.410 0.455 7 0.510 8 0.530 9 0.550 10 0.554 After blanking against a biuret-dH20 sample, the protein concentration of an unknown sample was determined using the same method and an absorbancy of 0.279 was obtained. Set up a standard curve, excluding outliers (experimental and statistical) and determine the protein concentration in the unknown sample in mg / ml (up to 3 significant figures).
Name two advantages of performing a mass spectrometry imaging experiment at high mass resolution (R.P. > 120000)