LABORATORY MANAGEMENT and QUALITY ASSURANCE

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LABORATORY MANAGEMENT and QUALITY ASSURANCE
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Introduction

• The analytical laboratory provides
  qualitative and quantitative data for use in
  decision-making. To be valuable, the data must
  accurately describe the characteristics and
  concentrations of constituents in the samples
  submitted to the laboratory. In many cases,
  because they lead to faulty interpretations,
  approximate or incorrect results are worse than
  no result at all.
• HANDBOOK FOR ANALYTICAL QUALITY CONTROL IN WATER
  AND WASTEWATER LABORATORIES, EPA 1979

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Quality Assurance - Defined

• Quality Assurance (QA) is a set of operating
  principles that, if strictly followed during
  sample collection and analysis, will produce data
  of known and defensible quality.
• The Accuracy of the analytical result can be
  stated with a high level of confidence.
• STANDARD METHODS, 18th EDITION, 1992

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Outline

• Laboratory Management
• Introduction to Quality Assurance Concepts

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Laboratory Management

• Who should be involved in laboratory management
  and quality assurance?

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Laboratory Management

• Everyone involved with the lab
• Person sampling
• Person running the test
• Person washing the glassware
• Person doing maintenance on the instruments
• Person interpreting the results

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Laboratory Management

• Quality Assurance Program
• Staff Organization and Responsibilities
• Sample Control and Documentation
• SOP for Analytical Methods Procedures
• Analyst Training Requirements
• Equipment Preventative Maintenance
• Calibration Procedures
• Corrective Actions
• Internal Quality Control Activities
• Performance Audits
• Data Assessment for Bias and Precision
• Data Validation and Reporting

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Laboratory Management

• Keys to Quality Assurance Program
• Documentation
• Communication
• Training
• Cross-Training
• Updating

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Sample Control and Documentation

• A record keeping system (paper trail, chain of
  custody) should track samples before, during, and
  after analysis.
• Everyone involved needs to understand and utilize
  the system.

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Sample Control and Documentation

• Efficiently process information through lab
  system while minimizing actual time spent
  recording data
• Keep it simple!
• Collect only the information you need

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Suggested Information - Field
Hayfield Site Influent
Date
Site
04-15-02 8am
Collected By
HS IN 1
Jim S.
Code
Conditions
Sunny, 75F
Comments
pH adjusted to lt2 with nitric acid Grab sample
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Suggested Information - Lab

• Date of analysis
• Laboratory technicians performing the analysis
• Results (including units)
• Analytical comments based on need to know
• Dilutions
• Interferences encountered

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SOP for Analytical Procedures

• Describes method in enough detail that an
  experienced analyst could obtain acceptable
  results.

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SOP for Cleanliness

• Labware cleaning procedures should be documented
  and all persons involved should be trained.

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Routine Cleaning Procedure

• Rinse glassware with tap water.
• Clean glassware with a solution of water and
  laboratory detergent.
• Rinse the glassware with an acidic solution
• 1.0 N HCl
• 6N HNO3 for regulatory reporting of heavy metals
• Rinse glassware at least 3X with DI water.

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Routine Cleaning Procedure (cont.)

• Glassware should be stored in a manner that
  prevents contamination from dust particles.
• Prior to analysis, rinse the glassware with
  sample to prevent contamination or dilution.

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SOP for Instrumentation Maintenance

• Preventative maintenance is the key to optimal
  instrument performance.
• Follow any maintenance program and guidelines
  suggested by the instrument manufacturer.
• Instrument manual
• Reduces instrument downtime
• Service Contracts with Manufacturers

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Analyst Training

• Sample Logging and Preservation
• Method SOPs
• Measuring
• Use of Volumetric glassware (pipettes, graduated
  glassware)
• Weighing / Use and care of Analytical Balance
• Washing and Care of Glassware

• Operation of Analytical Instrumentation
• Data Handling and Reporting
• Quality Control Activities
• Safety

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QUALITY ASSURANCE CONCEPTS
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Quality Assurance

• Quality Control

• Quality Assessment

• Certification of Analyst Competence
• Recovery of Known Additions
• Analysis of Standards
• Analysis of Reagent Blanks
• Calibration with Standards
• Analysis of Duplicates
• Maintenance of Control Charts

• Performance Evaluation Samples
• Performance Audits

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Quality Assurance

• Quality Control

• Quality Assessment

• Certification of Analyst Competence
• Recovery of Known Additions
• Analysis of Standards
• Analysis of Reagent Blanks
• Calibration with Standards
• Analysis of Duplicates
• Maintenance of Control Charts

• Performance Evaluation Samples
• Performance Audits

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Certification of Analyst Competence

• Demonstration of acceptable precision and
  accuracy for each analyst
• Minimum of four replicate analyses on a known
  standard
• Look for acceptable accuracy and precision
• Acceptable limits vary per analytical method
• Demonstration of Capability

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What is Accuracy?

• Accuracy is the nearness of a test result to the
  true value.

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What is Precision?

• Precision is how closely repeated measurements
  agree with each other.
• Although good precision suggests good accuracy,
  precise results can be inaccurate.

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Imprecise and inaccurate
Accurate but imprecise
Precise but inaccurate
Precise and accurate
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Quality Assurance

• Quality Control

• Quality Assessment

• Certification of Analyst Competence
• Recovery of Known Additions
• Analysis of Standards
• Analysis of Reagent Blanks
• Calibration with Standards
• Analysis of Duplicates
• Maintenance of Control Charts

• Performance Evaluation Samples
• Performance Audits

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Standards

• What is a standard?
• Solution containing a known amount of a specific
  substance
• Example 1.00mg/L iron standard

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Standards

• How are standards used?
• Instrument calibration
• Instrument verification/accuracy check
• Analyst training

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Standards

• Analysis of Known Standard Solutions Am I
  running the test correctly?
• Verifies instrument, technique, and reagents

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Standards

• Analysis of Known Standard Solutions
• How often?
• Daily, every Sample Batch?
• National Institute of Standards and Technology
• NIST

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Standards

• Recovery of Known Additions
• Is my sample compatible with the test?
• Identifies interferences and percent recovery
• Standard Addition
• Spiked sample

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1.00 mg/L
Correct??
1.20 mg/L
1.39 mg/L
1.58 mg/L
1.20 mg/L
1.40 mg/L
1.60 mg/L
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Calibration with Standards

• Some instruments have built-in calibration
  curves, not necessary to calibrate
• Instrument without preprogrammed calibration
  curves
• Prepare curve daily - OR
• Whenever a new lot of reagents is prepared

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Calibrations
mg/L

ABS
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pH Calibration Curve
180
mV
0
-180
4
10
7

pH
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Standards

• Its what I always get
• It meets the permit limit
• I did
• what the manual said
• what tech support said
• what you told me
• Its the same number the City of ____ gets

• I got what I expected
• Ive run standards
• Its a XXX brand instrument, the best!
• After 20 years you get a feel for it
• Im a chemist
• Its the same answer the lab got

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Quality Assurance

• Quality Control

• Quality Assessment

• Certification of Analyst Competence
• Recovery of Known Additions
• Analysis of Standards
• Analysis of Reagent Blanks
• Calibration with Standards
• Analysis of Duplicates
• Maintenance of Control Charts

• Performance Evaluation Samples
• Performance Audits

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Reagent Blanks

• Some reagents contribute color to a sample
• Quantifies amount of reagent contribution to
  color formation
• Monitors of purity of reagents
• On each new lot of reagents
• 5 of samples (Standard Methods)

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Reagent Blanks
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Reagent Blanks
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Quality Assurance

• Quality Control

• Quality Assessment

• Certification of Analyst Competence
• Recovery of Known Additions
• Analysis of Standards
• Analysis of Reagent Blanks
• Calibration with Standards
• Analysis of Duplicates
• Maintenance of Control Charts

• Performance Evaluation Samples
• Performance Audits

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Analysis of Duplicates

• Assesses precision
• 5 of sample need to be Duplicates
• (Standard Methods)

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Quality Assurance

• Quality Control

• Quality Assessment

• Certification of Analyst Competence
• Recovery of Known Additions
• Analysis of Standards
• Analysis of Reagent Blanks
• Calibration with Standards
• Analysis of Duplicates
• Maintenance of Control Charts

• Performance Evaluation Samples
• Performance Audits

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What is a Control Chart?

• Quality control (QC) measuring device that
  visually represents the QC data
• Information in a control chart can aid in
  determining
• Probable source of measurement variability
• Whether or not a process is in statistical control

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How do Control Charts Work?

• If the chart displays other than random variation
  around the expected result, it suggests a problem
  with the measurement process.
• Control limits are plotted on the chart, to
  assess whether this has happened. The
  measurement results are expected to remain within
  these limits.

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Normal Distribution
(Standard Deviation around the Mean)
2s
3s
1s
-1s
-2s
-3s
MEAN
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Confidence Limits
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2s
3s
1s
-1s
-2s
-3s
10.00
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Confidence Limits
95
2s
3s
1s
-1s
-2s
-3s
10.00
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Confidence Limits
99
2s
3s
1s
-1s
-2s
-3s
10.00
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Control Charts

• A control chart is essentially a normal
  distribution flipped on its side
• A control chart is a plot of
• Test units on the vertical scale
• Sequence of time on the horizontal scale

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Control Chart
3s
2s
1s
Mean
-1s
-2s
-3s
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Control Chart
3s
2s
Upper Warning Limit
1s
Mean
-1s
-2s
Lower Warning Limit
-3s
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Control Chart
3s
Upper Control Limit
2s
1s
Mean
-1s
-2s
-3s
Lower Control Limit
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How do Control Charts Work?

• Warning Limits
• Set at 2s
• Standard Methods suggests
• If 2 of 3 points are outside warning limits,
  analyze another sample. If it is within warning
  limits, continue. If it is outside warning
  limits, stop and troubleshoot.

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How do Control Charts Work?

• Control Limits
• Set at 3s
• Standard Methods suggests
• If any point is outside control limits, analyze
  another sample. If it is within control limits,
  continue. If it is outside control limits, stop
  and troubleshoot.

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How do Control Charts Work?

• A standard is measured regularly, and the results
  are plotted on the control chart.
• Control chart is a graph of concentration versus
  time.

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Control ChartIron Standard, FerroVer Procedure
UC L
3s
UW L
2s
1s
Mean
-1s
-2s
LW L
LC L
-3s
Time
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Constructing a Control Chart

• A control chart can be constructed in a variety
  of ways
• Graph paper
• Spreadsheet problem, such as Excel

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Constructing a Control Chart

• Analyze 10-15 replicates of a standard.
• Determine the mean and standard deviation.
• Calculate 2s and 3s
• Construct the control chart around the mean value
• Use 2s as the warning limits
• Use 3s as the control limits

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Example Iron Standard Replicates
Sample mg/L Iron
1 1.003
2 1.010
3 0.995
4 1.007
5 0.993
6 1.018
7 1.000
8 0.986
9 1.014
10 1.005
11 0.990
12 1.000
13 0.982
14 1.000
15 0.997
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Example Iron Standard Replicates

• Calculate
• Mean
• Standard Deviation (1s)
• 2s
• 3s

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Example Iron Standard Replicates

• Calculate
• Mean 1.000
• Standard Deviation (1s) 0.010 (0.990-1.010)
• 2s 0.020 (0.980-1.020)
• 3s 0.030 (0.970-1.030)

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Control ChartIron Standard, FerroVer Procedure
UC L
3s
UW L
2s
1s
1.00 mg/L
Mean
-1s
-2s
LW L
LC L
-3s
Time
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Constructing a Control Chart
First, set up a spreadsheet with columns for UWL,
LWL, UCL, LCL, and sample results
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Constructing a Control Chart
Fill in values for UWL, LWL, UCL, LCL, and sample
results
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Control ChartIron Standard, FerroVer Procedure
UC L
3s
UW L
2s
1s
1.00 mg/L
Mean
-1s
-2s
LW L
LC L
-3s
Time
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Constructing a Control Chart
Fill in values for UWL, LWL, UCL, LCL, and sample
results
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Constructing a Control Chart
Highlight data and create a graph
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Constructing a Control Chart
Format graph as necessary
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Example Control Charts

• Control Analysis Results Week 1

Sample mg/L Iron
Mon 1.003
Tues 0.995
Wed 1.006
Thurs 0.988
Fri 0.992
Sat 0.992
Sun 1.004
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Example Control Charts
Week 1 results display normal, random variation
between the UWL and LWL.
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Example Control Charts

• Control Analysis Results Week 2

Sample mg/L Iron
Mon 1.008
Tues 1.000
Wed 0.996
Thurs 0.993
Fri 0.989
Sat 0.988
Sun 0.983
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Example Control Charts
Week 2 Three or more points in one direction
indicates a possible bias in analytical results.
Investigate!
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Example Control Charts

• Control Analysis Results Week 3

Sample mg/L Iron
Mon 1.012
Tues 1.000
Wed 1.015
Thurs 0.986
Fri 0.994
Sat 0.968
Sun 0.997
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Example Control Charts
Week 3 Data has a high degree of scatter to the
LCL. Investigate!
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Quality Assurance

• Quality Control

• Quality Assessment

• Certification of Analyst Competence
• Recovery of Known Additions
• Analysis of Standards
• Analysis of Reagent Blanks
• Calibration with Standards
• Analysis of Duplicates
• Maintenance of Control Charts

• Performance Evaluation Samples
• Performance Audits

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Performance Evaluation Samples

• Standards provided by an outside agency
• Blind Samples

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Performance Audits

• Inspection to document sampling handling from
  receipt to final reporting of results
• To detect any variations from SOPs
• Checklists developed for each analysis type
• Sample entered in log book?
• Meter calibrated?
• Standard Analyzed?
• Etc., etc..

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LABORATORY MANAGEMENT and QUALITY ASSURANCE
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References

• Standards Methods
• Handbook for Analytical Quality Control in Water
  and Wastewater Laboratories
• EPA 1979
• Hach Water Analysis Handbook
• An Introduction to Standards and Quality Control
  for the Laboratory
• Barbara Martin, Hach Company