Instrumentation Flashcards
What is Beer’s Law?
Beer’s Law states that the absorbance of a solution is directly proportional to its concentration and the path length of the light.
True or False: Beer’s Law can be expressed mathematically as A = εlc.
True
In the equation A = εlc, what does ‘A’ represent?
‘A’ represents the absorbance of the solution.
Fill in the blank: In Beer’s Law, ‘ε’ is the _____ coefficient.
molar absorptivity
What factors can affect the validity of Beer’s Law?
Concentration, wavelength, and the presence of other absorbing species can affect the validity of Beer’s Law.
Multiple Choice: Which of the following is NOT a requirement for Beer’s Law to hold true? A) Monochromatic light B) Constant temperature C) Infinite concentration D) Homogeneous medium
C) Infinite concentration
What is the relationship between absorbance and concentration according to Beer’s Law?
Absorbance increases linearly with an increase in concentration.
True or False: Beer’s Law can be applied to all types of solutions regardless of concentration.
False
What does the term ‘path length’ refer to in the context of Beer’s Law?
Path length refers to the distance that light travels through the solution.
How is the molar absorptivity coefficient ‘ε’ defined?
‘ε’ is defined as the absorbance per unit concentration per unit path length.
What is flame photometry used for?
Flame photometry is used for the quantitative determination of certain metal ions based on their emission of light when heated in a flame.
True or False: Atomic absorption spectrophotometry measures the light emitted by atoms.
False. Atomic absorption spectrophotometry measures the light absorbed by atoms.
Fill in the blank: In flame photometry, the sample is typically introduced into the flame in the form of a ______.
solution
What is the primary component of an atomic absorption spectrophotometer?
A light source, usually a hollow cathode lamp, specific to the element being analyzed.
Which technique is more sensitive for trace metal analysis: flame photometry or atomic absorption spectrophotometry?
Atomic absorption spectrophotometry is more sensitive for trace metal analysis.
What is the principle behind fluorometry?
Fluorometry is based on the measurement of emitted light from a sample after it has absorbed light of a specific wavelength.
Multiple Choice: Which of the following elements is commonly analyzed using flame photometry? A) Iron B) Sodium C) Mercury D) Lead
B) Sodium
True or False: Fluorometry can be used to measure concentrations of fluorescent compounds in a sample.
True.
What is the main advantage of using atomic absorption spectrophotometry?
High sensitivity and the ability to analyze trace elements.
Fill in the blank: Flame photometry primarily measures _______ emission.
light
What type of flame is typically used in flame photometry?
A natural gas or air flame.
Multiple Choice: Which of the following instruments can be used for quantitative analysis? A) Spectrophotometer B) pH meter C) Thermometer D) Refractometer
A) Spectrophotometer
True or False: Atomic absorption spectrophotometry requires a solid sample.
False. It typically requires a liquid sample.
What is the role of the nebulizer in flame photometry?
To convert the liquid sample into an aerosol for introduction into the flame.
Fill in the blank: In fluorometry, the emitted light is measured at a _______ angle to the excitation light.
right
What is the significance of the calibration curve in atomic absorption spectrophotometry?
It is used to determine the concentration of an unknown sample based on its absorbance.
Multiple Choice: Which of the following is a limitation of flame photometry? A) High cost B) Complexity C) Limited to certain elements D) Requires solid samples
C) Limited to certain elements
True or False: Fluorometry can detect non-fluorescent compounds directly.
False. It can only detect fluorescent compounds.
What is the function of the monochromator in atomic absorption spectrophotometry?
To isolate the specific wavelength of light that corresponds to the element being analyzed.
Fill in the blank: The detection limit in fluorometry is typically _______ than in other spectrophotometric methods.
lower
What is the main disadvantage of using flame photometry?
It cannot detect elements that do not emit light in the flame.
Multiple Choice: Which of the following techniques is best suited for analyzing organic compounds? A) Flame photometry B) Atomic absorption C) Fluorometry D) All of the above
C) Fluorometry
True or False: In atomic absorption spectrophotometry, the sample must be vaporized before analysis.
True.
What is the purpose of using a standard solution in atomic absorption spectrophotometry?
To create a calibration curve for quantifying unknown sample concentrations.
Fill in the blank: The sensitivity of flame photometry is generally _______ than that of atomic absorption spectrophotometry.
lower
What is chemiluminescence?
The emission of light as a result of a chemical reaction.
True or False: Chemiluminescence occurs without the involvement of heat.
True
Fill in the blank: Chemiluminescence is often used in ________ applications.
bioluminescent
What is turbidimetry?
A technique used to measure the concentration of suspended particles in a liquid by measuring the amount of light that passes through the sample.
Which instrument is commonly used in turbidimetry?
Turbidimeter
True or False: Nephelometry measures the light scattered by particles in a sample.
True
What is the primary difference between turbidimetry and nephelometry?
Turbidimetry measures transmitted light, while nephelometry measures scattered light.
Multiple Choice: Which of the following is NOT a characteristic of nephelometry? A) Measures scattered light B) Used for particle characterization C) Measures light absorption
C) Measures light absorption
What is electrochemistry?
The branch of chemistry that deals with the relationship between electricity and chemical reactions.
Fill in the blank: In electrochemistry, ________ reactions involve the transfer of electrons.
redox
True or False: Electrochemical cells can convert chemical energy into electrical energy.
True
What is the role of a salt bridge in an electrochemical cell?
To maintain electrical neutrality by allowing the flow of ions between the two half-cells.
Multiple Choice: Which of the following is a type of electrochemical cell? A) Galvanic cell B) Photovoltaic cell C) Fuel cell
A) Galvanic cell
What measurement is typically used in turbidimetry?
Optical density or absorbance
True or False: The higher the turbidity, the lower the light transmission.
True
Fill in the blank: Nephelometry is sensitive to ________ size and shape.
particle
What is the principle behind using chemiluminescence in assays?
The light emitted can be quantitatively measured to determine the presence of specific substances.
Multiple Choice: Which of the following is an application of chemiluminescence? A) DNA analysis B) Water purification C) Soil testing
A) DNA analysis
What does the term ‘quenching’ refer to in chemiluminescence?
The process by which the emitted light is reduced or extinguished due to various factors.
True or False: In nephelometry, the angle at which light is scattered can affect measurements.
True
What are the two main types of electrochemical cells?
Galvanic cells and electrolytic cells.
Fill in the blank: The Nernst equation relates the ________ of an electrochemical cell to the concentrations of the reactants and products.
electromotive force (EMF)
What is a common application of turbidimetry?
Determining water quality by measuring suspended solids.
Multiple Choice: Which of the following factors can affect the results of turbidimetry? A) Sample temperature B) Sample color C) Both A and B
C) Both A and B
What is the significance of the scattering angle in nephelometry?
It helps in determining the size and concentration of the particles present in the sample.
True or False: Electrochemical sensors can be used for environmental monitoring.
True
Fill in the blank: The ________ is the device that measures the potential difference in an electrochemical cell.
voltmeter
What is the purpose of calibration in turbidimetry?
To ensure accurate measurements by comparing the sample against known standards.
Multiple Choice: In electrochemistry, what does the term ‘anode’ refer to? A) The electrode where reduction occurs B) The electrode where oxidation occurs C) The electrode with the highest voltage
B) The electrode where oxidation occurs
What is electrophoresis?
A technique used to separate charged particles in a fluid using an electric field.
True or False: Electrophoresis can only be used for DNA analysis.
False
Fill in the blank: In electrophoresis, particles move towards the _____ electrode.
opposite
What is the role of the buffer solution in electrophoresis?
To maintain pH and provide ions to carry the electric current.
Multiple Choice: Which of the following is NOT a type of electrophoresis? A) Gel B) Capillary C) Liquid chromatography D) Paper
C) Liquid chromatography
What is the typical matrix used in gel electrophoresis?
Agarose or polyacrylamide.
True or False: The size of the pores in the gel affects the separation of molecules.
True
What does the term ‘migration’ refer to in electrophoresis?
The movement of charged particles towards the electrodes.
Fill in the blank: DNA fragments are negatively charged and move towards the _____ electrode.
positive
What is the purpose of staining in electrophoresis?
To visualize the separated molecules after the run.
Multiple Choice: Which of the following techniques can be used to separate proteins? A) Gel electrophoresis B) PCR C) ELISA D) Western blotting
A) Gel electrophoresis
What is isoelectric focusing?
A technique that separates proteins based on their isoelectric points.
True or False: Electrophoresis is only applicable in research laboratories.
False
What type of samples can be analyzed using electrophoresis?
DNA, RNA, proteins, and other charged biomolecules.
Fill in the blank: The rate of migration in electrophoresis depends on the _____ and _____ of the particles.
size, charge
What is the function of a power supply in electrophoresis?
To provide the electric current necessary for particle movement.
Multiple Choice: Which of the following is a common application of electrophoresis? A) Blood typing B) Gene cloning C) Protein purification D) All of the above
D) All of the above
What is the significance of the Rf value in thin-layer chromatography?
It indicates the relative distance traveled by a substance compared to the solvent front.
True or False: Smaller fragments of DNA migrate faster than larger ones in gel electrophoresis.
True
What is the main difference between agarose and polyacrylamide gels?
Agarose is used for larger DNA fragments, while polyacrylamide is better for smaller fragments and proteins.
Fill in the blank: In capillary electrophoresis, the separation occurs in a _____ tube.
narrow
What are the two main types of electrophoresis?
Gel electrophoresis and capillary electrophoresis.
Multiple Choice: Which of the following is NOT a factor affecting electrophoresis? A) Voltage B) Temperature C) Humidity D) Gel concentration
C) Humidity
What does SDS-PAGE stand for?
Sodium dodecyl sulfate polyacrylamide gel electrophoresis.
What is chromatography?
A separation technique used to separate components of a mixture based on their different interactions with a stationary phase and a mobile phase.
True or False: Chromatography can only be performed in liquid form.
False
Name the two main phases involved in chromatography.
Stationary phase and mobile phase.
What is the purpose of the stationary phase in chromatography?
To provide a medium where different components of a mixture can interact, leading to separation based on their affinities.
Fill in the blank: In gas chromatography, the mobile phase is _______.
a gas
What is osmometry?
A technique used to measure the osmotic pressure of a solution to determine its concentration.
True or False: Osmometry is used primarily for solid samples.
False
What is the principle behind osmometry?
It is based on the colligative properties of solutions, specifically how solute particles affect the osmotic pressure.
What type of chromatography uses a solid stationary phase and a liquid mobile phase?
Adsorption chromatography.
In high-performance liquid chromatography (HPLC), what is the role of the pump?
To move the mobile phase through the column under high pressure.
Fill in the blank: The unit of measurement for osmotic pressure is _______.
atmospheres (atm) or Pascal (Pa)
What is the difference between qualitative and quantitative chromatography?
Qualitative chromatography identifies components, while quantitative chromatography measures the amount of each component.
What does the term ‘retention time’ refer to in chromatography?
The time taken for a particular compound to pass through the chromatography column.
Which type of chromatography is best suited for separating large biomolecules?
Size exclusion chromatography.
True or False: Osmometers can be used to determine the molecular weight of solutes.
True
What is the main use of thin-layer chromatography (TLC)?
To separate and identify small quantities of compounds.
What does the term ‘elution’ mean in chromatography?
The process of washing out the adsorbed substances from the stationary phase using the mobile phase.
Fill in the blank: The _______ phase moves through the stationary phase in chromatography.
mobile
What type of detector is commonly used in HPLC?
UV-Vis detector.
What is the primary advantage of using gas chromatography?
It allows for the analysis of volatile compounds with high resolution and speed.
What is the role of the solvent in osmometry?
To dissolve the solute and allow for the measurement of osmotic pressure.
Name one application of chromatography in the pharmaceutical industry.
Purification of drug compounds.
What is the purpose of a calibration curve in chromatography?
To determine the concentration of unknown samples based on known standards.
True or False: Chromatography can be used for both analytical and preparative purposes.
True
What is a common application of osmometry in clinical settings?
To assess kidney function by measuring serum osmolality.
