Module 5- Instrumentation Flashcards
True/False: spectrophotometers are classified as single or double beam
True
The relationship between absorption of light bya a solution and the concentration of that solution
Beer’s law
Used to measure the light transmitted by a solution to determine the concentration of the light-absorbing substance in the solution
Spectrophotometer
Most common light source for work in the visible ans near-infrared region
Incadescent tungsten or tungsten-iodide lamp
Lamps most commonly used for UV work
Deuterium-discharge lamp and the mercury-arc lamp
______ minimizes unwanted or stray light
Entrance slit
Most common cause of loss of linearity at high-analyte concentration
Stray light
Isolates individual wavelengths of light
Monochromator
Defines the range of wavelengths transmitted
Bandpass
Wedge-shaped pieces of glass, quartz, and sodium chloride
Prism
Most commonly used monochromator
Diffraction gratings
A monochromator that can split/isolate stray light
Filters
Allows only a narrow fraction of the spectrum to reach the sample cuvette
Exit slit
True/False: Accurate absorbance measurement requires a bandpass less than 1/4 the natural bandpass of the spectrophotometer
False, 1/5 dapat
Holds the solution whose concentration is to be measured
Cuvette/sample cell/absorption cell/ analytical cell
Used for applications requiring UV radiation
Quartz cuvette
True/False: Cuvette with scratches on their optical surface do not scatter light and should be discarded
False, bcs it scatters light
Converts the transmitted radiant energy into an equivalent amount of electrical energy
Photodetector
What are the 4 kinds of photodetector?
- Barrier layer cell/photocell/photovoltaic cell
- Phototube
- Photomultiplier tube
- Photodiode
A photodetector with low sensitivity but high/excellent linearity
Photodiode
A photodetector with excellent sensitivity and has rapid response; most commonly used detector
Photomultiplier tube
A photodetector that requires external voltage for operation
Phototube
______ is a temperature sensitive photodetector
Barrier layer cell/ photocell/ photovoltaic cell
Most useful as a simultaneous multichannel detector
Photodiode
Displays output of the detection system
Meter or read-out device
True/False: atomic absorption spectrophotometry is sensitive and precise
True
Enumerate the part of atomic absorption spectrophotometer (in sequence)
- Hollow-cathode lamp
- Chopper
- Flame
- Entrance slit
- Monochromator
- Exit slit
- Detector
- Read-out
Most common burner
Premix long-path burner
Enumerate the parts of a basic filter fluoremeter (in sequence)
- Light/source
- Attenuator
- Primary filter
- Sample holder
- Secondary filter
- Detector
- Read-out
Most frequently used sources of excitation radiant energy
Gas-discharge lamps (mercury and xenon-arc)
True/False: fluorometry increases specificity by selecting the optimal wavelength for both absorption and fluorescence
True
True/False: AAS is approx. 1000 times more sensitive than most spectrophotometric methods
False, it should be fluorometer
Modification of electrophoresis
Isoelectric focusing
Aka liquid-solid chromatography
Adsorption chromatography
Also referred as liquid chromatography
Partition chromatography
Uses pressure for fast separations, controlled temp., in-line detectors amd gradient elution techniques
Modern liquid chromatography
Current ultracentrifugation can spin as much as ___________ per minute
150, 000 rotations
Mechanization of the steps in a procedure; mimic the manual techniques in an analytical procedure
Automation
Continuous, single channel;approx. 40 samples per hour
First autoanalyzer (AA)
Desire to bring the laboratory testing to patient
Point-of-care testing
Law mandates that all labs must be regulated using the same standards regardless of location, type or size.
CLIA ‘88
Simple; low risk for incorrect result; performed by trained personnel
Waived POCT
