Exam 1 Lecture 1 Flashcards
what does analytical chemistry deal with?
methods for determining the chemical composition of samples of matter; classified as what do we have? and how much do we have?
what are qualitative methods?
deals with the identity of one or more constituents of a substance (ex: does this mineral contain copper?)
what are quantitative methods?
provide numerical info of these components (ex: does this mineral contain enough copper to be an economical source of copper?)
hcG
hormone related to pregnancy
how does a home pregnancy test work?
urine containing hcG is applied to the sample pad and moves down the conjugate pad which contains antibodies for hcG. hcG and antibodies bind and continue to move down until they bind to further antibodies. if pregnant, two lines will glow. the second line always glows because it binds a conjugate reagent to it’s antibody
what does it mean if the control line of a pregnancy test is not glowing?
it’s a faulty test; no conjugate reagant at all… no antibodies for the conjugate pad to attach to
what is the chemical analysis process?
sampling, sample preparation, chemical analysis
sampling (chemical analysis process)
procuring a representative sample to measure
(have to average many samples)
(ex: choosing the representative parts of the chocolate bar)
sample preparation (chemical analysis process)
preparing the sample for analysis through: removing interferents, weighing the sample, quantitatively transfer the sample for analysis
(ex: find out how much caffeine is in the sample)
interferent
a species other than the analyte increases or decreases the response of the analytical method (interferents give inaccurate results and skew data)
chemical analysis (chemical analysis process)
chromatography, calibration curve
chromatography
separates analytes and measures the quantity of each compound
calibration curve
measure detector response for known concentrations of each analyte, graph peak height vs. concentration, prediction step (the response signal obtained for the analyte and used to predict its concentration from the calibration curve or best-fit equation)
what are the general steps in chemical analysis?
formulate the question, select the analytical procedure, sample, prepare the sample, analyze, report and interpret, draw conclusions
electronic balance
uses electromagnetic force to compensate for a load placed on the pan
readability: the smallest increment of mass that can be indicated
microbalance: measures milligram quantities with a readability of 1 microgram