implementing standard operating procedures Proper maintenance and calibration of equipment Correct practices of laboratory personnel in performing analytical work Efficient management of laboratory records

QUALITY ASSURANCE IN THE ANALYTICAL CHEMISTRY LABORATORY Flashcards by Rochelle Lendio

is Defined as the degree to which a set
of inherent characteristics fulfill requirements.

Quality

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describes the overall measures that a
laboratory uses to ensure the quality of its operations.

Quality Assurance

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QA includes

 A quality systems
 Suitable laboratory environment
 Educated, Trained and skilled staff
 Equipment suitably maintained and calibrated
 Documented and validated methods.
 Traceability and measurement uncertainty
 Proficiency testing
 Requirements for reagents, standards, reference
materials

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Three of the most important components of laboratory
QA are:

QC
method validation
equipment maintenance

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is an integrated system of management and
technical activities within an organization that ensures
overall activities meet the defined standard or quality

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The QA program is defined in a documented
laboratory quality system which consists of:

QA Manual
QC processes
written management and technical
procedures
work instructions
records

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to ensure quality of
analytical data produced by the laboratory
and to demonstrate the competence of
the lab

QC processes

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Contains the quality policies and
objectives

QA Manual

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The most widely recognized and used QA
protocols and standards in chemical testing:

ISO/ IEC 17025:2005 (International
organization for standardization/ International
Electrotechnical Commission)

ISO 9001:2000

OECD Principles of Good Lab Practice
(organization for economic cooperation and
development)

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Standard which addresses the technical
competence of laboratories to carry out
specific tests and calibrations and is used by
lab accreditation bodies worldwide

ISO/ IEC 17025:2005 (International
organization for standardization/ International
Electrotechnical Commission)

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The standards which relates primarily to
quality management, for facilities carrying out
production, or providing services, including
chemical analysis

ISO 9001:2000

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International standard that contains all the
requirements that testing and calibration
laboratories have to meet if they wish to
operate a quality system

ISO/ IEC 17025:2005 (International
organization for standardization/ International
Electrotechnical Commission)

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Guidelines concerned with the organizational
processes and conditions under which
laboratory studies related to certain regulatory
work are carried out

OECD Principles of Good Lab Practice

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ISO/ IEC 17025 : 2005 MANAGEMENT
Requirements:

Organization
Management system
Document control
review of requests, tenders and contracts
Sub-contracting of tests and calibrations
Purchasing services and supplies
Service to the customer
Complaints
Control of non-conforming tests
Improvement
Corrective action
Preventive Action
Control of Records
Internal audits
Managements reviews

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ISO/ IEC 17025 : 2005 TECHNICAL
Requirements:

General
 2. Personnel
 3. Accommodation and environmental
condition
 4. Test and calibration method validation
 5. Equipment
 6. Measurement traceability
 7. Sampling
 8. Handling of test and calibration items
 9. Assuring the quality of test and calibration
results
 10. Reporting of results

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set of practice in the
chemical laboratory that controls the
laboratory activities and conditions that affect
the accuracy of analytical data

GLP ( limited sense)

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set of
requirements covering the organization of test
facilities and conditions to ensure the
generation of high quality and reliable test data
for specific objectives

GLP principles ( expanded sense)

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Component of GLP

QA Program
Laboratory Conditions
Test samples
Test measurements
Record management

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Component of GLP that ensures consistent quality of data

QA Program

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To preserve the identity and integrity of the
samples

Test samples

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To ensure that an acceptable test method
will produce the expected performance

Test measurements

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To ensure that laboratory conditions are
optimized to obtain the desired
performance of the test method

Laboratory Conditions

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To enable retrieval of undistorted
information whenever required

Record management

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GLP includes:

implementing standard operating
procedures
Proper maintenance and calibration of
equipment
Correct practices of laboratory personnel in
performing analytical work
Efficient management of laboratory records

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Ensures that the defined characteristics of the method as required are met. The defined method characteristics are also known as data quality objectives (DQOs)

Method of QA

are critical goals for accuracy, precision, sensitivity, and selectivity of analytical data to be satisfied so as to achieved analysis goals.

data quality objectives (DQOs)

Minimum requirements for Method of QA

Accuracy Precision Sensitivity Selectivity

degree of agreement of measurements with an acceptable reference value or degree of acceptable method bias. Bias ( sometimes called recovery) is the systematic error of the measuring system

Accuracy

degree of spread of results ( degree of differences in individual test results, expressed as standard deviation, relative standard deviation or RSD).

Precision

is defined by detection limits:

Sensitivity

the measured concentration at which there is a stated probability ( 95% or 99%) that an analyte is present. MDL is defined as 3x standard deviation (of method blank runs).

Method detection limit (MDL)-

the lowest concentration level that can be determined to be statistically different from the blank; the lowest analyte concentration required to be present to ensure an analytical response that will exceed the MDL.

Reliable detection limit (RDL)

the level above which quantitative results maybe obtained with a specified degree of confidence. Confidence in the apparent analyte concentration increases as the analyte signal increases above the MDL.

Limit of quantitation (LOQ)

Formula for LOQ

LOQ = 3.33 x MDL = 10 x s ( 99% CL)

susceptibility of the method to interferences. This maybe determined by recovery of spiked samples

Selectivity

A method QA program will:

Start with → DQOs Involve → Method selection , documentation and validation End with → Evaluation Continue with → QC monitoring and instrument maintenance Re-validation/ re-evaluation Improvement

Method of QA program covers:

 Method Selection  Method Validation  Sampling  Equipment  Quality Control  Traceability  Measurement Uncertainty  Proficiency Testing

Factors to consider when selecting a method:

* 1. Limit of detection * 2. precision * 3. Bias/Recovery * 4. Accuracy * 5. Selectivity * 6. Equipment required * 7. Sample size * 8. Time * 9. Cost * 10. Safety

Checks need to be carried out to ensure that the performance characteristics of a method are understood and to demonstrate that the method is scientifically sound under the conditions in which it is to be applied. These checks are collectively known as

Validation

Analytical procedures must be well documented before validation is performed. Documentation includes:

1. Title of test method 2. Scope and application 3. Sample matrices 4. Method detection level 5. Interferences 6. Safety considerations 7. Sample collection, preservation, transport, storage 8. Apparatus, equipment, and supplies 9. Reagents, standards, reference materials 10. actual test procedure: - Calibration - Standardization - Sample preparation - Calculations 11. Specific QC practices 12. Acceptance criteria 13. Tables, flowcharts, validation data 14. Estimation of measurement uncertainty 15. References

The inclusion of particular validation parameters in a validation protocol depends on the application, the test samples, the goal of the method, and domestic or international guidelines and regulations, as applicable. These include:

1. Selectivity and specificity ( description of the measurand) 2. Measurement range 3. Calibration and traceability 4. Bias 5. Linearity 6. Limit of detection/ LOQ 7. Precision 8. Ruggedness

Ways of performing validation of an analytical method:

1. Collaborative Validation 2. Internal Validation

a method is validated in a laboratory before use to prove that the method performs adequately

Internal Validation

Requires participation of a number of lab. Requires the use of a common sample of known concentration of the analyte. Results are evaluated for the collaborative mean value of the analyte. Assessment of the accuracy, precision, ruggedness and detection limits of the method

Collaborative Validation

Components of internal validation of methods:

Characterization of instrument calibration and working range Determination of sensitivity ( detection limits) Determination of bias ( systematic error) Determination of precision ( random error) Assessment of ruggedness ( for lab-developed methods and non-standard methods)

is incorporated in the routine analysis to maintain the performance of the method. It is also an evaluation program incorporated into routine and lab activities that assesses the accuracy and precision of measurements.

Quality Control

What are the three Quality Control Samples?

1. Laboratory instrument QC Samples 2. Laboratory method QC Samples 3. Field QC Samples

to measure and control the instrument calibrations or instrument performance.

Laboratory instrument QC Samples

solutions with certified concentration of analytes used to verify the accuracy of the calibration curve.

Lab Instrument Control Standard

one of the standard solutions used in making the calibration curve that verifies the stability of a calibration curve over time

Verification Standard

solution to check for instrument contamination and background levels.

Instrument Blank

assesses the precision of the test procedure

Lab sample replicate

The three Laboratory instrument QC Samples

Lab Instrument Control Standard Verification Standard Instrument Blank

Three Lab method QC Samples

Method blank Lab sample replicate Method analyte spike

What are the Method analyte spike

Blank spike Matrix spike Sample spike

measures the recovery of a method

. Method analyte spike

measures method contamination background

Method blank

analyte spiked on clean matrix to assess losses or contribution due to the matrix

Matrix spike

analyte spiked on samples to assess the losses or contribution due to other components or characteristics of the sample

Sample spike

analyte spiked on a method blank

Blank spike

Naturally- occurring materials or synthetic materials with known concentrations of analytes (obtained through collaborative studies) certified by recognized certifying bodies (such as NIST, IAEA) used to assess the bias of the method; comes with Certificate of Analysis.

Certified Reference Materials

Three field QC samples

Field Blank Field Analyte spike Field Replicate Samples

measures recovery between time of sampling and time of analysis

Field Analyte spike

measures contamination from sampling activities

Field Blank

Corrective action on failed QC includes:

* investigation when QC failure * correction of the cause of failure * institution of preventive measures to preclude the recurrence of failure * Investigation of QC failure can be started by identification of the trend in the QC chart.

The ______ and ______ of analytical measurement is the formal procedure of laboratory quality control. But _______ is the final stage of a management system of quality assurance

control of bias, random error quality control

susceptibility of the method to interferences. This maybe determined by recovery of spiked samples

Selectivity