5b-in-lab-assignment-emission-spectroscopy

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.

Instrumentation of IR spectroscopy?  Please answer at your own words.

In the fluorescence quenching of rhodamine B dye, the fluorescence decay of rhodamine B in the DMF-solution with ethanol-water mixture was monitored by measuring the 605 nm emission lifetime (decay of intensity over time) after a laser pulse. The lifetime (t) of rhodamine B in absence of quenchers is Do 2.10 ns. Quenching of rhodamine fluorescence by the presence of 2% ethanol- water mixture reduced the lifetime (T) to 1.86 ns. Using the following Stern-Volmer equation, what would be the rhodamine B emission lifetime in ns by changing the ethanol-water to 13 %? (Final answer should be of three significant figures) 1.142 To T = k₁ + k₂+k₂ [Q] k₁ + k₁₂

Please don't provide handwritten solution ....

7 of 10 > Atomic absorption spectroscopy was used to determine the amount of aluminum in a sample of sunscreen. A blank solution was measured seven times to determine the detection and quantitation limits of the spectrometer. The blank readings were: 0.0073, 0.0082, 0.0110, 0.0101, 0.0102, 0.0098, and 0.0090 AU. Determine the signal at the detection limit and the signal at the limit of quantitation for this method. signal detection limit: signal limit of quantitation: hulu étv 14

Infrared Spectroscopy (IR) is very useful for determining the functional groups present in an organic molecule. For each of the spectra below, complete the following: • Build the molecule in Spartan and describe the motion of the molecule at each key absorption frequency • Identify key absorption frequencies in the spectrum and identify the type of stretch/bend/wag/etc. (i.e. O-H) • Match the spectra from the provided structures • Identify the main functional groups in the molecule OH A OH H B E F H N NH2

Doing a Hw questions need help questoin 4 and 5 5. Organize from Highest to Lowest wavenumber

Explain why the information from an XPS chemical shift must also be contained in an X-ray absorption edge.

Given C6H12O2 chemical formula. chemical shift , intergration, multiplicity and interpretation needed.

In order to measure riboflavin in a breakfast cereal, a 5.00-gram sample of the cereal was extracted with acetic acid and filtered. The extract was transferred to a 50.0 mL volumetric flask and diluted to the mark. The sample was transferred to a cuvette and the fluorescence was measured. The instrument read 59 units (Fluorescence units –an arbitrary scale). 24.00 mL of the cereal extract was sample was mixed with 1.0 mL of a riboflavin standard that was 0.500 ug/mL. The fluorescence of this mixture was measured and read 94 fluorescence units. Calculate the concentration of riboflavin per gram of cereal (use µg/gram of cereal).

What are some of the advantages and limitations of mass spectroscopy?

Example: When a sample of 4-heptanone was irradiated with 313 nm radiation with a power output of 50 W under conditions of total absorption, it was found that the quantum yield 0.21. What is the number of ketone molecules dissociated down per second?

Calculate the mass and linear absorption coefficients of air for CrKα radiation. Assume that air contains 80 % N2 and 20 % O2 by weight and has a density of 1.29 x10-3g/cm3?

Find information on fluorescent dye Fluo-3: Display its structure Briefly describe its purpose and the mechanism of operation Display its fluorescence spectra Display transmission spectra of commercially available optical filters required for flow cytometry measurements of cells stained with Fluo-3 (see lecture notes on where to look)

Please what molecule is this