Organic Analytical Laboratory

Data management and data validation are part of the Organic Analytical Laboratory’s overall quality assurance program. Data must be assembled in a timely manner (data processing) and in a database format that permits efficient validation up to univariate Level 2. The Laboratory has developed software and utilizes up-to-date computer systems to automate the data processing and reporting functions.

Data Management

• All data are stored in a secure and available file server system that provides a central storage area for laboratory and field data.
• Databases have defined structures and are maintained in one area so that all field names will be consistent, permitting easy merging and comparison of various databases.
• All data are backed up on tape cartridges at regular intervals. Redundant backups of critical data are retained to prevent loss due to a failure of the backup media.
• The Organic Analytical Laboratory computers are in an isolated local area network that cannot be accessed by outside computers.
• A history file is maintained to record the date, time, and name of the individual making changes to any file.
• Chromatogram files bind the calculations with the file, preventing accidental changes in the data as a result of calibration changes.
• Data tables are produced automatically using standard report formats designed for each project. Gas chromatography/mass spectrometry data and gas chromatography/infrared detector data can be combined in a single report.
• Integrated mass spectrometry and infrared searches are conducted utilizing the NIST Mass Spectral Library (more than 43,000 mass spectra) and the EPA IR Library (more than 4,000 IR spectra).

Data Validation 

• Data from the field, laboratory, and quality control activities are unified prior to reporting.

• Organic Analytical Laboratory procedures address deviations from measurement assumptions and procedures.

• Level I and II sample validation can be conducted by the Organic Analytical Laboratory.

Data Processing

• Accurate data is combined into a single database for each type of analysis.
• Uncertainty analysis is conducted to allow the presentation of data with absolute uncertainties associated with each number in the report.
• For chromatographic analysis, a data signal is collected and stored as digitized data by the computer system which generates reports using the appropriate response factors.
• Carbonyl analyses are tabulated by an in-house data processing system.
• A customized database program for canister measurements facilitates the identification of reference peaks and permits the generation of several report formats as well as merger into a master database of identified compounds for the project.

Computer Systems

Laboratory computers and data processing computers are linked using a LANtastic ethernet computer network rated at 10 megabytes/second.

Quality assurance is achieved through integration of quality control, quality auditing, measurement method validation, and data validation. The Laboratory maintains a quality assurance program to ensure the integrity and reliability of its own operation and can also design and implement quality assurance programs for external studies (Custom Analysis/Services).

The objectives of the Laboratory’s quality assurance measures are:

1. Maintaining a continuing assessment of the quality of data generated by analysts working in the laboratory;
2. Providing a permanent record of instrument performance as a basis for validating data and projecting repairs and replacement needs;
3. Ensuring sample integrity;
4. Maintaining accurate records;
5. Producing analytical results that can withstand scientific and legal scrutiny.
   

As a routine part of the Organic Analytical Laboratory’s on-going quality assurance activities, parameters related to precision, accuracy, and completeness are continually monitored. The quality control system is based on standard operating procedures tested and established for all sampling, analysis, and data processing.Standard operating procedures include, when applicable, a statement of purpose, a list of required equipment and forms, specification of calibration standards, step-by-step procedures including a process flow diagram, a quantification procedure, tolerances for performance tests, and an audit protocol. Standard operating procedures are reviewed and updated as necessary to incorporate feedback from the field and laboratory as well as audit results.

Precision is monitored by multiple-point calibration curves and by duplicate analyses of samples. Accuracy is confirmed by blind interlaboratory comparisons. DRI has experienced excellent results in the following comparison studies:

• International Hydrocarbon Intercomparison Experiment sponsored by the National Center for Atmospheric Research.
• NARSTO-Northeast Hydrocarbon Intercomparison Study (the DRI Organic Analytical Laboratory performed the best in comparison with all other participants).
• Non-methane hydrocarbon laboratory performance audits organized by the Quality Assurance Section, Monitoring and Laboratory Division, California Air Resources Board.
• Analysis of the standard hydrocarbon mixture employed by the Environmental Protection Agency in the Photochemical Assessment Monitoring Stations monitoring program.
• Auto/oil round-robin comparison study for analysis of hydrocarbon and carbonyl compounds sponsored by the Coordinating Research Council.

Accuracy is further ensured through use of the National Institute of Standards (NIST) standards for calibration of the flame ionization detectors and other NIST and NIST-traceable standards for calibration of the other instruments.

Completeness is addressed through systematic calibration of systems used for qualitative analysis combined with an extensive data management system to provide rapid and accurate determination of the presence or absence of targeted compounds.