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CHEM 129 > Exam 2 > Flashcards

Exam 2 Flashcards

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1
Q

Which of the following is NOT a primary objective of method validation?
A. Reliability, Accuracy, and Precision
B. Fitness-for-Purpose
C. Confidence in Data
D. Maximizing Errors and Uncertainty
E. Quality Assurance and Regulatory Compliance

A

D. Maximizing Errors and Uncertainty

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2
Q

What does specificity mean in the context of analytical chemistry?
A. The ability of a method to detect small amounts of analyte.
B. The capacity of an analytical method to distinguish and measure the analyte of interest with minimal interference from other substances.
C. The range of analyte concentrations over which a method is reliable.
D. The degree to which an analytical method produces consistent results.
E. The ability of a method to be unaffected by small changes in operating parameters.

A

B. The capacity of an analytical method to distinguish and measure the analyte of interest with minimal interference from other substances.

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3
Q

A calibration curve is used to assess which method validation parameter?
A. Specificity
B. Linearity
C. Accuracy
D. Precision
E. Range

A

B. Linearity

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4
Q

Which technique is commonly employed to evaluate the accuracy of an analytical method?
A. Analyzing blank samples
B. Spiking samples with known concentrations of analyte
C. Measuring the signal-to-noise ratio
D. Introducing deliberate variations in operating parameters
E. Examining the y-intercept of the calibration curve

A

B. Spiking samples with known concentrations of analyte

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5
Q

Repeatability is a measure of which aspect of precision?
A. The variation observed when an assay is performed by different people on different instruments on different days.
B. The reproducibility observed when aliquots of the same sample are analyzed by different people in different laboratories.
C. The reproducibility observed when the same quantity of one sample is repeatedly introduced into an instrument.
D. The variation observed when an assay is performed by different people on different instruments on the same day.
E. The reproducibility observed when aliquots of a homogeneous material are analyzed several times by one person on one day.

A

C. The reproducibility observed when the same quantity of one sample is repeatedly introduced into an instrument.

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6
Q

What is the key difference between Instrument Detection Limit (IDL) and Method Detection Limit (MDL)?
A. IDL focuses on the sensitivity of the instrument, while MDL considers the entire analytical procedure.
B. IDL is determined using a single sample, while MDL requires multiple replicates.
C. IDL is a theoretical limit, while MDL is a practical limit.
D. IDL is calculated with analyte dissolved “neat,” while MDL is calculated with analyte dissolved in a sample matrix.
E. IDL is always lower than MDL.

A

D. IDL is calculated with analyte dissolved “neat,” while MDL is calculated with analyte dissolved in a sample matrix.

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7
Q

The Limit of Quantitation (LOQ) represents:
A. The lowest concentration of analyte that can be consistently detected.
B. The smallest amount of analyte that can be measured with reasonable accuracy.
C. The upper limit of analyte concentration that a method can accurately measure.
D. The concentration of analyte that produces a signal equal to three times the noise level.
E. The point at which the uncertainty of measurement increases significantly.

A

B. The smallest amount of analyte that can be measured with reasonable accuracy.

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8
Q

Which of the following is a graphical tool used in quality control to visualize the relationships between two variables?
A. Flow chart
B. Cause-and-effect diagram
C. Histogram
D. Scatter plot
E. Control chart

A

D. Scatter plot

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9
Q

What is the primary function of a method blank in analytical chemistry?
A. To calibrate the instrument before analysis.
B. To account for interference by other species in the sample and for traces of analyte found in reagents.
C. To determine the recovery of a spiked sample.
D. To assess the reproducibility of the analytical method.
E. To establish the limit of detection of the analyte.

A

B. To account for interference by other species in the sample and for traces of analyte found in reagents.

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10
Q

What is the purpose of a spike recovery experiment?
A. To determine the concentration of analyte in an unknown sample.
B. To evaluate the linearity of the calibration curve.
C. To assess the robustness of the analytical method.
D. To test whether the response to a sample is the same as that expected from a calibration curve.
E. To determine the limit of quantitation of the analyte.

A

D. To test whether the response to a sample is the same as that expected from a calibration curve.

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11
Q

T/F: Accuracy refers to the degree of repeatability and reproducibility of the measured values obtained from an analytical method.

A

False. Precision refers to the degree of repeatability and reproducibility of measured values.

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12
Q

T/F: The limit of detection (LOD) is always lower than the limit of quantitation (LOQ).

A

True

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13
Q

T/F: Quality assurance focuses solely on fulfilling quality requirements, while quality control focuses on providing confidence that quality requirements will be fulfilled.

A

False. Quality Control focuses on fulfilling quality requirements and Quality Assurance focuses on providing confidence that quality requirements will be fulfilled.

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14
Q

T/F: Random sampling is a technique used to reduce bias and ensure that each element in the population has an equal chance of being included in the sample.

A

True.

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15
Q

T/F: A false positive result indicates that the analyte concentration is below the legal limit when it is actually above the limit.

A

False. A false negative result indicates that the analyte concentration is below the legal limit when it is actually above the limit.

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16
Q

T/F: Control charts are graphical tools used to monitor the performance of analytical procedures over time.

A

True

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17
Q

T/F: Statistical process control (SPC) is primarily used in research laboratories to optimize experimental conditions.

A

False. It is primarily used in the manufacturing industry.

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18
Q

T/F: A flow chart is a graphical representation of the steps involved in an analytical procedure.

A

True

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19
Q

T/F: A cause-and-effect diagram is a tool used to identify potential causes of a problem or issue.

A

True

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20
Q

Which of the following is NOT a primary objective of method validation in analytical chemistry?
(A) Reliability, Accuracy, and Precision
(B) Fitness-for-Purpose
(C) Maximizing Profit
(D) Confidence in Data

A

(C) Maximizing Profit

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21
Q

Method validation ensures that analytical methods consistently produce results that are:
(A) Biased and Inaccurate
(B) Reliable, Accurate, and Precise
(C) Subjective and Unreliable
(D) None of the Above

A

(B) Reliable, Accurate, and Precise

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22
Q

Which regulatory agencies mandate that analytical methods meet specific validation criteria?
(A) FBI and CIA
(B) FDA and EPA
(C) WHO and UNESCO
(D) NATO and ASEAN

A

(B) FDA and EPA

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23
Q

What does sensitivity mean in the context of analytical method specificity?
(A) Being able to distinguish analyte from other species in the sample
(B) The capability of responding reliably and measurably to changes in analyte concentration
(C) The ability of an analytical method to provide test results that are directly proportional to the concentration of the analyte
(D) The smallest quantity of analyte that is “significantly different” from the blank

A

(B) The capability of responding reliably and measurably to changes in analyte concentration

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24
Q

A specific method should be sensitive enough to detect and quantify the analyte even in the presence of:
(A) High levels of interferents
(B) Low levels of interferents
(C) Moderate levels of interferents
(D) All of the above

A

(B) Low levels of interferents

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25
Q

What does a linear response in an analytical method simplify?
(A) Sample preparation
(B) Data interpretation
(C) Instrument calibration
(D) Statistical analysis

A

(B) Data interpretation

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26
Q

Which of the following is NOT a step in assessing the linearity of an analytical method?
(A) Plot Calibration Curve
(B) Examine R²
(C) Determine the Limit of Detection
(D) Check Residuals

A

(C) Determine the Limit of Detection

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27
Q

What does accuracy quantify in an analytical method?
(A) The method’s ability to provide results that are in agreement with the actual values
(B) The degree of repeatability and reproducibility of the measured values
(C) The concentration or measurement interval over which the analytical method is suitable for its intended purpose
(D) The smallest quantity of analyte that is “significantly different” from the blank

A

(A) The method’s ability to provide results that are in agreement with the actual values

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28
Q

What is the formula for calculating recovery in accuracy assessment?
(A) (True Value / Measured Value) x 100%
(B) (Measured Value / True Value) x 100%
(C) (True Value - Measured Value) / True Value x 100%
(D) (Measured Value - True Value) / Measured Value x 100%

A

(B) (Measured Value / True Value) x 100%

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29
Q

What does precision measure in analytical chemistry?
(A) The closeness of the measurement to the true value
(B) The degree of repeatability and reproducibility of the measured values
(C) The concentration range over which the method is linear
(D) The smallest amount of analyte that can be detected

A

(B) The degree of repeatability and reproducibility of the measured values

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30
Q

Which type of precision is evaluated by analyzing aliquots of a homogeneous material several times by one person on one day with the same equipment?
(A) Instrument precision
(B) Intra-assay precision
(C) Intermediate precision
(D) Interlaboratory precision

A

(B) Intra-assay precision

31
Q

What is intermediate precision also known as?
(A) Repeatability
(B) Ruggedness
(C) Reproducibility
(D) Accuracy

A

(B) Ruggedness

32
Q

Which type of precision is considered the most general measure of reproducibility?
(A) Instrument precision
(B) Intra-assay precision
(C) Intermediate precision
(D) Interlaboratory precision

A

(D) Interlaboratory precision

33
Q

What does range define in an analytical method?
(A) The smallest amount of analyte that can be detected
(B) The degree of closeness between measured and true values
(C) The concentration or measurement interval over which the method is suitable for its intended purpose
(D) The degree of repeatability of measurements

A

(C) The concentration or measurement interval over which the method is suitable for its intended purpose

34
Q

What is the difference between the linear range and the dynamic range of an analytical method?
(A) The linear range is the concentration range over which the calibration curve is linear, while the dynamic range is the concentration range over which there is a measurable response.
(B) The dynamic range is the concentration range over which the calibration curve is linear, while the linear range is the concentration range over which there is a measurable response.
(C) The linear range includes the dynamic range.
(D) The dynamic range includes the linear range

A

(A) The linear range is the concentration range over which the calibration curve is linear, while the dynamic range is the concentration range over which there is a measurable response.

35
Q

What is the limit of detection (LOD)?
(A) The highest concentration of analyte that can be accurately measured
(B) The lowest concentration of an analyte in a sample that can be consistently detected with a stated probability
(C) The range of concentrations over which the method is accurate
(D) The degree of reproducibility of the method

A

(B) The lowest concentration of an analyte in a sample that can be consistently detected with a stated probability

36
Q

What does the signal-to-noise ratio method for determining LOD tell you?
(A) The accuracy of the measurement
(B) Whether the peak you are seeing is real or just part of the background noise
(C) The linearity of the calibration curve
(D) The precision of the method

A

(B) Whether the peak you are seeing is real or just part of the background noise

37
Q

What is the difference between instrument detection limit (IDL) and method detection limit (MDL)?
(A) IDL is calculated with analyte dissolved “neat,” while MDL is calculated with analyte dissolved in a sample matrix.
(B) MDL is calculated with analyte dissolved “neat,” while IDL is calculated with analyte dissolved in a sample matrix.
(C) IDL is always lower than MDL.
(D) MDL is always lower than IDL.

A

(A) IDL is calculated with analyte dissolved “neat,” while MDL is calculated with analyte dissolved in a sample matrix.

38
Q

What is the limit of quantitation (LOQ)?
(A) The smallest amount of analyte that can be detected
(B) The smallest amount that can be measured with reasonable accuracy
(C) The concentration at which the signal is 3 times greater than the noise
(D) The concentration range over which the method is linear

A

(B) The smallest amount that can be measured with reasonable accuracy

39
Q

What is robustness in analytical chemistry?
(A) The ability of a method to withstand extreme temperatures
(B) The ability of a method to produce accurate results even with contaminated samples
(C) The ability of a method to be unaffected by small, deliberate changes in operating parameters
(D) The ability of a method to be used by different analysts with consistent results

A

(C) The ability of a method to be unaffected by small, deliberate changes in operating parameters

40
Q

Which experimental design can be used to control method variables when assessing robustness?
(A) Latin Square Design
(B) Randomized Block Design
(C) Factorial and Fractional Factorial Design
(D) Completely Randomized Design

A

(C) Factorial and Fractional Factorial Design

41
Q

Which of the following is a general definition of quality?
(A) Delivering a product or service that does not meet specifications
(B) Satisfying customer requirements
(C) Creating products with defects
(D) None of the above

A

(B) Satisfying customer requirements

42
Q

Data quality standards according to the US EPA include:
(A) Get the wrong data
(B) Get the data right
(C) Discard the data
(D) None of the above

A

(B) Get the data right

43
Q

What is the definition of a quality system according to the Association of Official Analytical Chemists International?
(A) A system for recording and analyzing customer complaints
(B) A system for ensuring the safety of laboratory personnel
(C) A management system to direct and control an organization with regard to quality
(D) A system for tracking the financial performance of a laboratory

A

(C) A management system to direct and control an organization with regard to quality

44
Q

What is the focus of quality assurance?
(A) Identifying and correcting defects in products
(B) Providing confidence that quality requirements will be fulfilled
(C) Reducing manufacturing costs
(D) Increasing production speed

A

(B) Providing confidence that quality requirements will be fulfilled

45
Q

Which of the following is NOT a system of quality assurance in analytical laboratories?
(A) Good Laboratory Practice (GLP)
(B) Accreditation of a laboratory according to EN 45001 or ISO Guide 17025
(C) Certification according to norms ISO of series 9000
(D) Hazard Analysis and Critical Control Points (HACCP)

A

(D) Hazard Analysis and Critical Control Points (HACCP)

46
Q

What does the Valid Analytical Measurement (VAM) program emphasize?
(A) Cost-effectiveness of analytical measurements
(B) Speed of analytical measurements
(C) Making reliable analytical measurements
(D) Simplifying analytical procedures

A

(C) Making reliable analytical measurements

47
Q

What are raw data in analytical chemistry?
(A) Statistical summaries of measurements
(B) Individual values of a measured quantity
(C) Final reported results
(D) Calibration curves

A

(B) Individual values of a measured quantity

48
Q

What do specifications in analytical chemistry outline?
(A) The desired profit margins for analytical testing
(B) The marketing strategies for analytical services
(C) How good the numbers need to be and what precautions are required in the analytical procedure
(D) The legal regulations governing analytical laboratories

A

(C) How good the numbers need to be and what precautions are required in the analytical procedure

49
Q

Which sampling method involves dividing the population into subgroups based on certain characteristics?
(A) Random Sampling
(B) Stratified Sampling
(C) Systematic Sampling
(D) Purposive Sampling

A

(B) Stratified Sampling

50
Q

Which sampling method is often used when the researcher wants to study particular characteristics or conditions?
(A) Random Sampling
(B) Stratified Sampling
(C) Systematic Sampling
(D) Purposive Sampling

A

(D) Purposive Sampling

51
Q

What is quartering in sampling?
(A) Dividing a sample into four equal portions for analysis
(B) Analyzing a sample four times to ensure accuracy
(C) Storing a sample in a container with four compartments
(D) None of the above

A

(A) Dividing a sample into four equal portions for analysis

52
Q

Which type of error is typically more important to minimize in analytical chemistry: false positives or false negatives?
(A) False Positives
(B) False Negatives
(C) They are equally important to minimize
(D) It depends on the specific situation

A

(B) False Negatives

53
Q

What does a method blank account for in analytical measurements?
(A) The presence of the analyte in the sample
(B) Interference by other species in the sample and traces of analyte in reagents
(C) The accuracy of the instrument
(D) The precision of the method

A

(B) Interference by other species in the sample and traces of analyte in reagents

54
Q

What is a spike in analytical chemistry also known as?
(A) Contaminant
(B) Fortification
(C) Interferent
(D) Blank

A

(B) Fortification

55
Q

What are performance test samples used for in quality control?
(A) Calibrating instruments
(B) Preparing standards
(C) Eliminating bias introduced by an analyst who knows the concentration
(D) Determining the LOD of a method

A

(C) Eliminating bias introduced by an analyst who knows the concentration

56
Q

What is the purpose of control charts in analytical chemistry?
(A) To record experimental data
(B) To plan experimental procedures
(C) To monitor performance on blanks, calibration checks, and spiked samples
(D) To calculate statistical parameters

A

(C) To monitor performance on blanks, calibration checks, and spiked samples

57
Q

What is the main aim of statistical process control (SPC)?
(A) To increase production costs
(B) To reduce defects, or non-conforming items
(C) To complicate manufacturing processes
(D) To make processes less capable

A

(B) To reduce defects, or non-conforming items

58
Q

What does a flow chart in analytical chemistry illustrate?
(A) The chemical structure of an analyte
(B) The statistical distribution of data
(C) The linear structure of a chemical analysis in time
(D) The relationship between two variables

A

(C) The linear structure of a chemical analysis in time

59
Q

What is another name for a cause-and-effect diagram?
(A) Pareto chart
(B) Control chart
(C) Scatter plot
(D) Ishikawa diagram

A

(D) Ishikawa diagram

60
Q

True or False: The primary objectives of method validation include ensuring the method’s performance characteristics do not meet the requirements of the analytical task at hand.

A

False. The primary objectives of method validation include ensuring the method’s performance characteristics do meet the requirements of the analytical task at hand.

61
Q

True or False: Method validation is a one-time process.

A

False. Method validation is not a one-time process but involves ongoing monitoring and assessment.

62
Q

Specificity refers to the ability of an analytical method to accurately identify and measure the analyte of interest in the presence of potential interferents.

A

True.

63
Q

True or False: Linearity is the ability of an analytical method to provide test results that are indirectly proportional to the concentration of the analyte.

A

False. Linearity is the ability of an analytical method to provide test results that are directly proportional to the concentration of the analyte.

64
Q

True or False: Accuracy ensures that the results generated by the analytical method are invalid and unreliable.

A

False. Accuracy ensures that the results generated by the analytical method are valid and reliable.

65
Q

Precision is essential in quality control processes, particularly in industries like pharmaceuticals and environmental monitoring.

A

True.

66
Q

The dynamic range of an analytical method always includes the linear range.

A

True.

67
Q

The limit of detection (LOD) is the highest concentration of an analyte in a sample that can be consistently detected.

A

False. The limit of detection (LOD) is the lowest concentration of an analyte in a sample that can be consistently detected.

68
Q

The instrument detection limit (IDL) is obtained by preparing multiple individual samples and analyzing each one once.

A

False. The method detection limit (MDL) is obtained by preparing multiple individual samples and analyzing each one once, while the IDL is obtained by replicate measurements of aliquots from one sample.

69
Q

Robustness ensures that an analytical method is significantly affected by small, deliberate changes in operating parameters.

A

False. Robustness ensures that an analytical method is unaffected by small, deliberate changes in operating parameters.

70
Q

Quality control aims to obtain measurement results with a low level of quality.

A

False. Quality control aims to obtain measurement results with the required quality level.

71
Q

Statistical process control (SPC) is rarely used in the manufacturing industry.

A

False. Statistical process control (SPC) is used largely in the manufacturing industry.

72
Q

A flow chart is a suitable graphical representation of the frequency distribution of a set of measurements.

A

False. A histogram is a suitable graphical representation of the frequency distribution of a set of measurements, while a flow chart illustrates the linear structure of a chemical analysis in time.

73
Q

A cause-and-effect diagram is also known as a Pareto chart.

A

False. A cause-and-effect diagram is also known as an Ishikawa diagram or fishbone diagram. A Pareto chart is a different type of chart.

74
Q

Scatter plots are ineffective in identifying outliers in data.

A

False. Scatter plots are effective in identifying outliers in data.

CHEM 129 (4 decks)

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