Module 8 Flashcards
On a quantitative HPLC chromatogram, which feature separates/distinguishes one compound from another? Which feature gives information about the amount (concentration) of each compound present?
retention time (how long it takes for a particular compound to move through the long, thin column before arriving at the detector); total peak size
A pure and validated sample of a phytochemical, which is used to calibrate analytic instruments and for purposes of comparison when performing quantitative analyses, is called a __________.
reference standard,
A researcher is examining a ‘new’ medicinal plant extract to see if it is a richer source of compound X (a non-volatile compound) than the plant currently being used in commerce. Which sort of analytical technique would be best suited for determining the concentration of the desired analyte?
HPLC (used for both quantitative and qualitative); TLC and LC are better for separating compounds, but not so useful for quantifying them. GC/MS is more effective for isolation and characterization of a volatile compound.
__________ is the name of the analytical technique which is most commonly used to determine how much lead is in a sample of herbal material or in a dietary supplement such as calcium. It can also be used for the quantitative analysis of minerals and trace elements.
Atomic Absorption Spectrophotometer (AAS)
The technique which is often used to analyze an herbal extract, by examining it for a number of different characteristic compounds, and by determining the concentrations of those compounds, is called __________. It is often used to profile an herb for quality control and identification purposes.
Fingerprinting (A number of different processes can be used for fingerprinting including HPLC, FTIR, and GC/MS.)
The spectroscopy technique which uses a large magnet and radio waves to induce characteristic vibrations in the nuclei of the atoms making up molecules is called __________. FTIR, MS, NMR, AAS
NMR – nuclear magnetic resonance (Each type of atom gives a recognizable resonance pattern which is influenced by the numbers and kinds of electrons in its neighborhood)
Which of the following analytical processes is not a type of chromatography used for separating the components of medicinal plant extracts? LC, HPLC, NMR, TLC
NMR
Which of the following techniques would be the most logical to use when analyzing the essential oil from a ‘new’ medicinal plant that had never been investigated by scientists?
GC/MS (gas chromatography/mass spectrometry) - GC is good at separating the volatile constituents of the oil, while MS helps to determine their structures once they have been separated.
In thin-layer chromatography, the __________ is very polar and is composed of __________; the __________ is much less polar and is made up of __________.
stationary phase; silica gel; mobile phase; solvent,
If a phytochemist wants to identify some plant material to make sure it is not adulterated or contaminated with undesired species, she might use HPLC to seek the presence of specific __________ which are characteristic of the intended species, but are not found in possible adulterants.
marker compounds - can be any type of molecule that is easy to detect and is always present in the plant material being analyzed.
