CPC CPC Quality Assurance & Standards

Question 1

In analytical chemistry, precision refers to:

Accepted Answer

The reproducibility of repeated measurements under the same conditions

Answer

How close a measurement is to the true value

Answer

The lowest detectable concentration of an analyte

Answer

The linear range of an instrument's response

Question 2

A standard reference material (SRM) issued by NIST is used in analytical chemistry to:

Accepted Answer

Validate measurement accuracy and ensure traceability to national standards

Answer

Replace calibration curves in routine analysis

Answer

Determine the precision of an analytical method

Answer

Establish method detection limits

Question 3

The method detection limit (MDL) in EPA methodology is defined as the minimum concentration that can be:

Accepted Answer

Distinguished from zero with 99% confidence (based on 7-replicate study)

Answer

Detected with any certainty

Answer

Measured with 10% relative standard deviation

Answer

Detected above instrument background noise

Question 4

ISO/IEC 17025 accreditation for testing laboratories requires which key element?

Accepted Answer

A documented quality management system with defined competence, impartiality, and consistent operation

Answer

Use of only commercially available test methods

Answer

At least 10 years of laboratory operation

Answer

Annual third-party instrument calibration only

Question 5

A control chart in a laboratory quality system shows a sample mean outside the ±3σ control limits. This indicates:

Accepted Answer

A likely out-of-control condition requiring investigation

Answer

Normal analytical variation

Answer

The method has exceeded its linear range

Answer

Calibration drift below acceptable limits

Question 6

Which of the following is an example of a Type B uncertainty evaluation in measurement uncertainty estimation?

Accepted Answer

Using calibration certificate uncertainty values and equipment specifications

Answer

Calculating standard deviation of repeated measurements

Answer

Performing duplicate analyses at different concentrations

Answer

Running a proficiency test sample