113 Questions
Which type of photometer uses optical filters to isolate a narrow wavelength range of spectrum?
Transmitted
What is the purpose of a spectrophotometer?
To determine the amount of a compound present in a solution
In which regions of the spectrum does laboratory spectrophotometry typically involve light?
Ultraviolet and visible regions (290-800nm)
Which type of detector is 200 times more sensitive than the phototube?
PMT
What does the term 'blanking the instrument' refer to?
Removing unwanted readings from the regent or the sample
Which check should be performed to ensure the wavelength indicated on the control dial is the actual wavelength of light passed by the monochromator?
Wavelength accuracy
According to Beer's Law, which of the following conditions can cause a deviation from linearity of the absorbance versus concentration curve?
All of the above
Which of the following is NOT a limitation of Beer's Law?
Fluorescence
Which component of a spectrophotometer is responsible for measuring the amount of light transmittance?
Detector
Which type of light source provides intense radiation of a narrow wavelength?
Laser
Which type of filter produces monochromatic light based on the principle of constructive interference of waves?
Interference Filters (Fabry-Perot)
Which type of filter offers linear dispersion of light over the entire UV and visible range?
Gratings
Which type of filter gives a non-linear separation of bands and requires several wavelengths to be measured for proper wavelength calibration?
Prisms
What is the bandpass of a monochromator?
The range of wavelengths transmitted
Which type of cuvette is optimal for spectrophotometry due to its plane-parallel optical surfaces and less error from the lens effect, orientation, and refraction?
Square cuvettes
Which factor affects the sensitivity of spectrophotometry by increasing the sample size?
Sample volume
Which type of detector in spectrophotometry is 200 times more sensitive than a phototube and is used in instruments that are very sensitive to very low light levels?
Photomultiplier tube
What is the purpose of a detector in spectrophotometry?
To convert the transmitted radiation energy into an equivalent amount of electric energy
According to Beer's Law, which of the following is true about the relationship between absorbance and concentration?
Absorbance and concentration are directly proportional
What is the mathematical relationship between absorbance (A), molar absorptivity (ε), concentration (c), and light path (b) according to Beer's Law?
A = εbc
What is the relationship between wavelength and energy according to Planck's formula?
Energy is inversely proportional to wavelength
What is the purpose of using a blank or reference solution in absorption spectroscopy?
To eliminate factors such as reflection and solvent absorption
Which type of filter offers linear dispersion of light over the entire UV and visible range?
Gratings
Which type of filter gives a non-linear separation of bands and requires several wavelengths to be measured for proper wavelength calibration?
Prisms
What is the bandpass of a monochromator?
The range of wavelengths transmitted by the monochromator
What factors determine the bandpass of a monochromator?
The light intensity output of the source and the efficiency of the system to isolate wavelength bands
Which type of detector in spectrophotometry is 200 times more sensitive than a phototube and is used in instruments that are very sensitive to very low light levels?
PMT
What is the purpose of a spectrophotometer?
To detect and measure the amount of light absorbed or transmitted by a sample
Which check should be performed to ensure the wavelength indicated on the control dial is the actual wavelength of light passed by the monochromator?
Wavelength accuracy check
Which of the following is the correct definition of photometry?
The measurement of the luminous intensity of light or the amount of luminous light falling on a surface from a specific source
Which type of instrument is used to indirectly determine the amount of a compound present in a solution by shining a light of a specific wavelength through the solution and measuring how much was absorbed?
Spectrophotometer
What is the mathematical relationship between absorbance (A), molar absorptivity (ε), concentration (c), and light path (b) according to Beer's Law?
A = εbc
Which of the following conditions can cause a deviation from Beer's Law, resulting in variations from linearity of the absorbance versus concentration curve?
Very low concentrations are measured
Which type of light source in spectrophotometry provides intense radiation of a narrow wavelength?
Laser
Which type of filter in spectrophotometry produces monochromatic light based on the principle of constructive interference of waves?
Grating
What is the mathematical relationship between absorbance (A), molar absorptivity (ε), concentration (c), and light path (b) according to Beer's Law?
A = εbc
Which type of cuvette is recommended for spectrophotometry due to its plane-parallel optical surfaces and less error from the lens effect, orientation, and refraction?
Square cuvette
What is the main advantage of using a photomultiplier tube (PMT) as a detector in spectrophotometry?
It is more sensitive to low light levels
Which type of detector in spectrophotometry generates its own electromotive force and does not require an external voltage source?
Barrier layer cell
Which factor affects the sensitivity of spectrophotometry by increasing the sample size?
Sample volume
According to Beer's Law, which of the following is true about the relationship between absorbance and concentration?
Absorbance is directly proportional to concentration
What is the mathematical relationship between absorbance (A), molar absorptivity (ε), concentration (c), and light path (b) according to Beer's Law?
A = εbc
What is the purpose of using a blank or reference solution in absorption spectroscopy?
To eliminate the contribution of the solvent and other factors
What is the relationship between wavelength and energy according to Planck's formula?
Energy is inversely proportional to wavelength
Which of the following statements is true about electrochemical potential?
It is the force required to move electrons in a chemical reaction
What is the role of a salt bridge in electrochemistry?
To maintain equilibrium between the two electrodes
Which metal is more electronegative in the redox couple of Zinc and Copper?
Zinc
Which of the following is NOT an application of potentiometry?
Measurement of glucose in serum
What is the main component of potentiometric techniques that measures the desired analyte(s)?
Indicator electrode
Which type of membrane is commonly used in ion-selective electrodes (ISEs)?
Polymer membrane
What is the purpose of a pO2 electrode in clinical chemistry?
Measurement of oxygen concentration in whole blood
Which of the following best describes the purpose of mass spectrometry?
To identify and determine the elemental composition and structure of compounds
What does a mass spectrometer measure?
The mass-to-charge ratio of ionized molecules and their fragments
What happens to a molecule that enters a mass spectrometer without a charge?
It is ionized and given a charge
Which ionization method uses a corona discharge needle to initiate gas phase reactions that ionize compounds through a series of ion molecule reactions?
APCI
Which ionization method is considered 'hard' and fragments molecules to pure atoms at the atomic level?
ICP
Which ionization method uses a laser energy absorbing matrix to create ions?
MALDI
Which mass analyzer is most commonly used and allows only ions of a single selected m/z value to pass through to the detector?
Quadrupole
Which component is required in all mass spectrometers to prevent ions from colliding with each other or other molecules during analysis?
Vacuum system
What is the unfragmented ion called when a molecular ion breaks into smaller pieces?
Molecular ion
Which ionization technique in mass spectrometry results in the mass spectrum being dominated by fragment ions?
Electron Ionization (EI)
Which ionization technique in mass spectrometry results in very little fragmentation during the process?
Chemical Ionization (CI)
Which of the following statements is true about time of flight (TOF) mass spectrometry?
TOF is used for the analysis of biomolecules
What is the main purpose of MALDI-TOF in microbiology?
To identify pathogenic bacteria and fungi
How does the time of flight (TOF) in a mass spectrometer vary with the mass of the ions?
Larger ions require more time to reach the detector
Which type of instrument is commonly used for drug screening applications and can measure large numbers of analytes simultaneously in complex biological matrices?
Triple quad
What is the purpose of the second quadrupole (Q2) in a triple quad instrument?
To collide the sample with neutral gas and fragment the ions
Which type of mass spectrometry instrument is capable of identifying genetic diseases and diseases with proteins, and is often used in proteomics research?
High-resolution mass spec
What is the purpose of an electron multiplier in a mass spectrometer detector?
To amplify the overall signal
Which type of chromatography uses gas as the mobile phase?
Gas Chromatography
What is the purpose of the stationary phase in gas-solid chromatography?
To retain chemicals by adsorption
What is one disadvantage of gas-liquid chromatography?
Column bleed
Which type of liquid is commonly used as the stationary phase in partition chromatography?
Polar liquid
What is the main purpose of affinity chromatography?
To separate analytes based on biologically related interactions
What is the most common material used for packing in high-performance liquid chromatography (HPLC)?
Silica gel
Which type of detector is commonly used in high-performance liquid chromatography (HPLC) to monitor the eluate?
Photodiode array
Which type of chromatography uses a liquid mobile phase and a solid stationary phase?
Liquid chromatography
Which type of chromatography uses a gas mobile phase and a solid stationary phase?
Gas chromatography
What is the measure of retention in thin-layer chromatography?
Distance compounds have traveled in a given amount of time
Which type of chromatography is primarily used for qualitative analysis?
Planar chromatography
Which type of chromatography is considered the gold standard for most testing due to its high sensitivity and specificity?
Liquid Chromatography
What is the term used to describe the average time or volume that is required for a chemical to pass through the column in chromatography?
Retention time
Which phase in chromatography carries the sample components and travels through the system?
Mobile phase
What is the purpose of a chromatograph in chromatography?
To provide a response related to the amount of a compound exiting from a column
Which of the following is a clinical application of osmometry?
Analyzing osmolality in urine, plasma, and serum
What is osmolality?
The concentration of solute particles relative to the mass of the solvent
Which physical properties of a solution are measured in osmometry?
Colligative properties
Which of the following is NOT a colligative property affected by the addition of a solute to a solvent?
Elevation in the osmotic pressure
What is the purpose of osmometry in a medical laboratory?
To assess fluid and electrolyte balance
Which of the following is the major contributor to serum osmolality?
Na+
What is the formula to calculate serum osmolality in SI units?
2(Na mmol/L) + Glucose (mmol/L) + Urea (mmol/L)
Which of the following is NOT a benefit of laboratory automation?
Increased production of results
What is the term used to describe the transport of a quantity of analyte or reagent from one specimen reaction into and contaminating a subsequent one?
Carry-over
Which type of chemistry analyzer uses continuous flow and pumps reagent non-stop through large amounts of plastic tubing?
Continuous Flow
Which component of automation is responsible for determining which tests need to be performed on a specimen?
Instrument interfaces
Which method of specimen delivery should NOT be used for stat or irreplaceable specimens?
Pneumatic tubes
Which phase of handling specimens is one of the most error-prone?
Preanalytical phase
Which type of devices are commonly used for point-of-care testing (POCT)?
Handheld or benchtop devices
What is the disadvantage of using a batch analyzer?
It can only run one test at a time for many specimens
What is the advantage of using a random access analyzer?
Each specimen and its reagents are independent of other specimens
What is the purpose of bar-coding in automated analyzers?
To prevent clerical errors in entering patient data
What is the purpose of laboratory information systems (LISs)?
To report results and manage QC data
Which term describes the overall stability of an antibody-antigen complex, based on affinity, the number of binding sites available, and the way the two molecules combine?
Avidity
Which type of antigen has the strongest avidity due to having more binding sites?
IgM
What is the term used to describe the zone in a precipitation curve where there is an excess of antibodies?
Prozone
Which type of immunoassay requires a separation step to physically separate free from bound analyte?
Heterogeneous immunoassay
In which zone of antigen excess is there a gradual decrease in the amount of precipitation until finally no precipitation is observed?
Postzone
Which particle method is a passive diffusion method in which a concentration gradient is established for a single reactant, usually the antigen?
Radial Immunodiffusion (RID)
Which label method uses radioactive isotopes of iodine and tritium as labels?
Radioimmunoassay (RIA)
Which immunoassay technique uses a chemiluminescent compound to detect analytes?
Chemiluminescent microparticle immunoassay (CMIA)
Which immunoassay technique is a non-competitive sandwich assay?
Sandwich immunoassay
Which immunoassay technique uses fluorescence to measure the concentration of analytes?
Fluorescence Polarization Immunoassay (FPIA)
What is the most common error seen in sandwich immunoassays at very high antigen concentrations?
High-Dose Hook Effect
Test your knowledge on Interference Filters (Fabry-Perot) with this quiz! Discover the principles behind these filters and their applications in producing monochromatic light. Get ready to dive into the world of constructive interference and explore the use of semi-transparent silver films and thin layers of magnesium fluoride.
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