QC 2 M1L3 - from exam

Mull technique, Kbr pellet, Liquid petrolatum

Ways to prepare the sample for infrared determination

Water is NOT used as solvent

• Strongly absorbs most of the IR radiation

• Destroy NaCl cells

Nephelometry

Based on the measurement of light that is reflected.

Flame Spectroscopy

• Used in the assay of metallic element (Na, K, Li, Ca) in the blood

  • Atomic emission

  • Atomic absorption

Fluorometry Application

Analysis of organic compounds

Fluorometry Application

Differentiating malignant from benign skin tumor

Fluorometry Application

Analysis of vitamin B1 (Thiamine) and B2 (Riboflavin)

Turbidimetry Application

Assay of antibiotics

Turbidimetry Application

Assay of calcium pantothenate and vit B12 (cyanocobalamin)

Turbidimetry Application

Standardization of bacterial concentration

Lamps, Monochromator

Parts of Spectrophotometer

Lamps

• Tungsten (visible)

• Deuterium (uv)

• Xenon (alternative)

Monochromator

Used to isolate the desired wavelength from the broadband radiation

Cuvette

• Glass cuvette (visible)

• Quartz / Fused silica (uv)

• Plastic

Solvent in IR

• Chloroform – commonly used solvent

• Carbon disulfide

• Benzene

• Dioxane

• Cyclohexane

Mass Spectrum

 usually presented as a bar graph

Photocell

 simplest detector type

Phototube

 more sensitive than the photocells

Photomultiplier

sensitive and produce fast response

Nujol

 white hydrocarbon oil

Fluorolube

 perfluorinated mineral oil

Criteria for a Good Solvent

• Good solubilizing property

• Chemically inert

• Solvent transparency

Matrix Materials for Pellet Making

• Kbr

• KCl

• NaCl

• CsI