This mean rtioning to occur the mobile has to be

  • No School
  • AA 1
  • 63

This preview shows page 20 - 31 out of 63 pages.

This mean rtioning to occur the mobile has to be nonpola l nonpolar mobile phases are n-hexane, ethya oform etc. arious solvents interact with the silica gel whic tant towards understanding the separations. lly a Langmuir isotherm adsorption behavior i ved.
Image of page 20

Subscribe to view the full document.

SEM IMAGE OF MONIDISPERSE Si SEM IMAGE OF MONIDISPERSE Si PARTICLES PARTICLES Average Particle size = 5 m
Image of page 21
NORMAL PHASE SEPARATIONS NORMAL PHASE SEPARATIONS a is used as the stationary phase then the sta is polar due to the presence of ionizable OH s. The mobile phase must be nonpolar in orde ve separations. nts will adsorb on the surface of Si particles an an be described by the Langmuir isotherm. = ac/(b + ac) action of the surface covered by the solvent o oncentration in the mobile phase = constants
Image of page 22

Subscribe to view the full document.

NORMAL PHASE SEPARATIONS (CONTD) (CONTD) ADSORPTION OF DIFFERENT ADSORPTION OF DIFFERENT SOLVENTS FROM n-HEPTANE SOLVENTS FROM n-HEPTANE
Image of page 23
LIQUID CHROMATOGRAPHY LIQUID CHROMATOGRAPHY DETECTORS DETECTORS s that elute from a column need to be detected chromatogram. Detector is a critical compon C system. The following types of detectors ar ible detector escence detector ical conductivity detector ctive index detector spectral detector activity detector
Image of page 24

Subscribe to view the full document.

UV-VISIBLE DETECTORS UV-VISIBLE DETECTORS
Image of page 25
SINGLE WAVELENGTH DETECTOR SINGLE WAVELENGTH DETECTOR ngle wavelength detectors consist of the following omponents: A low pressure mercury discharge lamp that emits lig the UV and visible regions. A focusing quartz lens. A cut-off filter (broad band or band-pass) that allows pecific wavelength ranges to be transmitted to the ample. Reference and sample cells of small volume microliters). Photomultiplier or photo cells to monitor the bsorption of light. Absorbance is calculated from Beer’s law: Log I T /I O = l c = A
Image of page 26

Subscribe to view the full document.

VARIABLE WAVELENGTH DETECTOR VARIABLE WAVELENGTH DETECTOR
Image of page 27
VARIABLE WAVELENGTH DETECTOR (CONTD) (CONTD) e wavelength detector consists of the following nents: uterium and or tungsten lamp to cover the uv and spectral ranges. mating mirrors that focus the source beam on to ction grating. The diffraction grating resolves omatic beam into its component wavelengths. ctral resolution is a function of the number of the grating. This arrangement allows a specific ngth to be chosen for detecting the analytes. all volume cell into which the eluting mobile phas s in the front and back of the cell to focus the giv ngth light into the sample and the transmitted lig e photomultiplier.
Image of page 28

Subscribe to view the full document.

FLUORESCENCE DETECTOR FLUORESCENCE DETECTOR
Image of page 29
FLUORESCENCE DETECTOR FLUORESCENCE DETECTOR orescence detector has the following components: polychromatic light source such as as a xenon lamp. his light is focused onto a diffraction grating which ws the excitation wavelength to be chosen. he chosen wavelength light is passed through the ple and reference cells. he light emitted from the sample cell is collected at o the incident light.
Image of page 30

Subscribe to view the full document.

Image of page 31
  • Fall '19

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern

Ask Expert Tutors You can ask 0 bonus questions You can ask 0 questions (0 expire soon) You can ask 0 questions (will expire )
Answers in as fast as 15 minutes