Quality Assurance of Chemical Measurements

Taylor, John K.

• Preface -- CHAPTER 1. Introduction to Quality Assurance -- CHAPTER 2. Precision, Bias, and Accuracy -- Axioms -- Corollaries -- Sources of Error -- Errors of Rounding -- Influence of Uncertainty on Decision -- CHAPTER 3. Statistical Control -- CHAPTER 4. Statistical Techniques -- Basic Requirements -- Distributions -- Statistics of Measurements -- Estimation of Standard Deviation -- Estimation of Standard Deviation from Replicate -- Measurements -- Estimation of Standard Deviation from Duplicate -- Measurements -- Estimation of Standard Deviation from the Range -- Pooling Estimates of Standard Deviations -- The Analysis of Variance -- Do Two Estimates of Precision Differ? -- What are the Confidence Limits for an Estimate of a -- Standard Deviation? -- Confidence Interval for a Mean -- Does a Measured Value Differ from an Expected -- Value? -- Do the Means of Two Measured Values Disagree -- Significantly? -- Statistical Tolerance Intervals -- Pooling Means to Obtain a Grand Average -- Outliers -- Rejection for an Assignable Cause -- Rule of the Huge Error -- Statistical Tests -- Dixon Test for Outlying Observations -- Grubbs Test for Outlying Observations -- Youden Test for Outlying Laboratories -- Cochran Test for Extreme Values of Variance -- Statistics of Control Charts -- Control Limits -- Central Line Considerations -- Agreement With Established Value -- Has the Central Line Changed? -- Use of Random Number Tables -- CHAPTER 5. Chemical Analysis as a System -- Systematic Approach to Analysis -- Effective Problem Solving -- CHAPTER 6. The Model -- Importance of a Model -- Development of a Model -- Data Quality Objectives -- CHAPTER 7. Planning -- General Aspects of Planning -- Development of an Experimental Plan -- Content of a Measurement Plan -- CHAPTER 8. Principles of Sampling -- Initial Considerations -- Sampling Plan -- Peer Review -- Training -- Sample Management -- Problem of Subsampling -- Critical Matters Related to Samples -- Quality Assurance of Sampling -- Sample Uncertainties -- Stratification -- Holding Time -- Statistical Considerations in Sampling -- Measurement Situations -- Statistical Sampling Plan -- Basic Assumptions -- Guidance in Sampling -- Cost Considerations -- Minimum Size of Increments in a Well-Mixed -- Sample -- Size of Sample in Segregated Materials -- Acceptance Testing -- Matrix-Related Sampling Problems -- Sampling Gases -- Sampling Liquids -- Sampling Solids -- Sampling Multiphases -- CHAPTER 9. Principles of Measurement -- Terminology -- Measurement is a Comparison Process -- Principles of Chemical Measurement -- Figures of Merit -- Precision -- Sensitivity -- Limit of Detection and Limit of Quantitation -- Short-term and Long-term Standard Deviation -- Bias -- Selectivity -- Other Considerations -- Importance of an SOP -- Ruggedness Testing -- Standardization of Methods -- Selection of Appropriate Methodology -- Guidelines for Selecting Instrumentation -- Internal vs External Services -- CHAPTER 10. Principles of Calibration -- What Needs to be Calibrated -- Requirements for Calibration -- Frequency of Calibration -- Mode of Calibration -- Linear Relationships -- Tests for Linearity -- Calibration Uncertainties -- Intercalibration -- Additional Remarks -- CHAPTER 11. Principles of Quality Assurance -- CHAPTER 12. Principles of Quality Control -- Competence -- Suitable Facilities and Equipment -- Good Laboratory and Good Measurement Practices -- Standard Operations Procedures -- Distinction Between GLPs, GMPs, and SOPs -- Protocols for Specific Purposes -- Contents of a PSP -- Other Quality Control Techniques -- Inspection -- Documentation -- Training -- The Quality Control System -- CHAPTER 13. Blank Correction -- Sources of Blanks -- Control of Blanks -- Evaluation of Blanks -- Statistical Treatment of the Blank -- Significance -- CHAPTER 14. Control Charts -- Format -- Control Limits -- Evaluating Control Limits -- Control Samples -- Frequency of Control Measurements -- Identification of Population -- Strategy of Use -- Assignment of Uncertainty -- Range Control Charts -- Approach -- Use of Range Control Charts -- Sub span Range Control Charts -- Range Performance Charts -- Range Ratio Control Charts -- Collateral Control Charts -- Critical Collateral Measurement Control Charts -- Recovery Control Charts -- Other Useful Control Charts -- Additional Remarks -- Blinds vs Double Blinds -- CHAPTER 15. Principles of Quality Assessment -- Internal Techniques -- External Techniques -- Qualitative Identification -- Other Techniques -- CHAPTER 16. Evaluation Samples -- Prime Requirements -- Types of Evaluation Samples -- Liquid Samples -- Solid Samples -- Gas Samples -- Stability of Mixtures -- Subsampling -- Integrity of Evaluation Samples -- CHAPTER 17. Reference Materials -- Role of Reference Materials -- Uses of Reference Materials -- Certification of Reference Materials -- CHAPTER 18. Traceability -- Chemical Traceability -- Standards Prepared by the Analyst -- Standards Prepared by Others -- Physical Standards -- Reference Materials Produced by NBS -- Reference Materials Produced by Others -- Traceability of Analytical Results -- Concept of the National Measurement System -- CHAPTER 19. Quality Audits -- Internal Audits -- Internal Systems Audits -- Internal Performance Audits -- Mechanism -- Corrective Actions -- External Audits -- Independent Audits -- Forms -- Personal Quality Assurance Profile -- Laboratory Quality Assurance Profile -- Quality Assurance Survey -- Quality Assurance Practices Check List -- Quality Assurance Training Profile -- CHAPTER 20. Quality Circles -- Organization -- Objectives -- Operation -- Reporting -- Agenda -- CHAPTER 21. Validation -- Validation of Samples -- Validation of Methodology -- Validation of Data -- CHAPTER 22. Reporting Analytical Data -- Minimum Requirements -- Data Limitations -- Numerical Values -- Limits of Uncertainty for Data -- Significant Figures -- Guidelines for Reporting Results of Measurements -- Guidelines for Combining Data Sets -- Arbitrary Reporting Procedures -- Reporting Low-Level Data -- Report Format -- CHAPTER 23. An Improved Approach to Performance -- Testing -- Premises -- Advance Estimation of Precision -- Performance Testing Plan -- Diagnosis -- Feedback -- Consensus Values -- Statistical Treatment of Data -- CHAPTER 24. Correction of Errors and/or Improving -- Accuracy -- Identification of Problems -- Improvement of Performance -- Editing Data -- CHAPTER 25. Laboratory Evaluation -- Generic Guidelines for Evaluation -- Accreditation -- Self-Evaluation -- CHAPTER 26. The Quality Assurance Program -- Approaches to Quality Assurance -- Quality Assurance Policy -- Planning for Quality Assurance -- Development of a QA Program -- Quality Assurance Manual -- Federally Mandated Quality Assurance Programs -- Public Health Service -- Food & Drug Administration -- Environmental Protection Agency – Non federally Mandated Quality Assurance Programs -- Quality Assurance for Measurement Programs -- Relating Personnel to Quality Assurance -- Appendix A. Terminology Used in Quality Assurance -- Appendix B. Quality Assurance Program Documentation -- B. l Example Quality Assurance Program Document -- B.2 Outline for Use in Preparing an SOP for a -- Measurement Method -- B.3 Outline for Use in Preparing an SOP for -- Calibration -- B.4 Outline for Use in Preparing a GLP or GMP -- Appendix C. Statistical Tables -- C.l Use of Range to Estimate Standard Deviation -- C.2 Z-Factors for Two-Sided Confidence Intervals -- for the Normal Distribution -- C.3 Student t Distribution -- C.4 Factors for Computing Two-Sided Confidence -- Intervals for E. -- C.5 Factors for Computing Two-Sided Confidence -- Intervals for a Normal Distribution -- C.6 Critical Values for the F Test -- C. 7 Values for Use in the Dixon Test for Outliers -- C.8 Values for Use in the Grubbs Test for Outliers -- C.9 Values for Use in the Youden Test for Outliers -- C.10 Values for Use in the Cochran Test for Extreme -- Variance -- C.11 Short Table of Random Numbers -- Appendix D. Study Aids -- D. l Seventy-Five Terms Commonly Used in -- Discussing Quality Assurance -- D.2 Seventy-Five Top