U2- Analytical Flashcards
making a standard solution from a primary standard
weigh the pure solid on an electronic balance
transfer to a volumetric flask using a clean, dry funnel
rinse any remains particles into flask w deionised water
add deposed water uo to the calibration line of the neck of the flask
stopper the flask and shake the solution to ensure an even conc throughout
burette and conical flask
burette contains titrant delivered to conical flask until end point is reached
conical flask contains known vol of analyte and (usually) an indicator that makes the end point observable
colorimetry
determines the concentration of a substance by measuring the relative absorption of light (usually visual) compared to other solutions containing known concentrations of that substance.
spectroscopy
we observe the change to light itself as a result of its interaction with a substance
absorption of light
object absorbs all wavelengths of light other than the colour it appears eg red paint absorbs all wavelengths other than red light: red light is reflected.
Red cellophane is red due to the absorption of non-red wavelengths. However, red light is transmitted through the cellophane
complementary colours
complementary colour of light being reflected is being absorbed most strongly
ROYGBV
GBVROY
parts of colorimetry
light source is passed through a filter that selects a particular wavelength of light for analysis
a cuvette holds the sample (glass, plastic, quarts)
an electronic detector measures absorption of light that passes through the cell
calibration
known concentration against absorption. can only interpolate data
beer-lambert law
absorbance is proportional to concentration at low absorbance values
base peak
highest peak/most abundant freagment
parent peak
peak with the highgest m/z value (the whole molecule that has lost 1 e)
fragmentation
when high energy electrons ionise a sample by knocking off an electron in a bond, breaking the bond and producing fragments
