The Merlin AutoGC Xplorer (MAX) is a cloud-based database designed to ingest data generated by chromatographic equipment deployed into EPA Photochemical Assessment Monitoring Sites (PAMS) which are collecting and analyzing hourly concentrations of up to 60 volatile organic compounds (VOC). MAX is a Structured Query Language (SQL) database of the data which includes the necessary information to allow users to view and graphically evaluate the hourly concentration data from these sites.
Orsat, LLC has developed and designed MAX to accommodate data originating from either PerkinElmer Ozone Precursor systems or Agilent systems using Markes International pre-concentration sampling system. These analytical systems incorporate a thermal desorption sampling system, a gas chromatographic system capable of separating the VOCs of interest and an chromatographic data system to integrate and quantitate the resulting chromatographic output. The format of the data from the chromatographic data system is generally an ASCII text output which has been formatted specifically for ingestion into the MAX system. Currently data formats for ingestion into MAX are available for the PerkinElmer Totalchom and Agilent OpenLab EZChrom edition chromatographic data systems.
The PAMS AutoGC systems collect not only hourly ambient air data but also have Quality Control samples which are outlined in the EPA PAMS Technical Assistance Guidance document (TAD). While most agencies have large databases capable of accumulating ambient data for review by policy makers, they do not always have the ability to review large amounts of quality control data associated with these highly technical systems. MAX was designed specifically to allow program managers, operators and data validators to review both the ambient data and the quality control samples to evaluate in near real-time the performance of their systems. Multiple QC sample types are specified by the EPA TAD to reconcile the performance of each analyzer.
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The output format for data generated by the analytical data system must adhere to a specific ASCII text format to enable MAX to be able to correctly interpret and store the data. Orsat has generated output formats for both the Totalchrom and EZChrom data systems. The user will not only need this format for the output but will need their analytical method to adhere to specific requirements such as target names, response factor format and calibration units. Orsat can assist by supplying methods for each analytical and help the user to implement any necessary changes that might be required.
* Required Input from Analytical System
MAX was designed to identify the QC control samples by using a specific file naming paradigm. Thus filenames must be specific to the sample type. Filenames are generated using a sequence generator which assigns filenames and schedules the necessary QC samples in the analytical system. This requires specific automation not generally provided as part of the original manufacturers product. Orsat offers the necessary hardware and software to generate not only the sequences with descriptive filenames but also the hardware to automate the introduction of the necessary QC samples for both the PerkinElmer and Agilent systems.
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In order to allow the evaluation of these QC samples each data set or Site has a definition which incorporates configuration parameters for the Network which defines information about incoming data such as a list of target VOCs, which targets will be in the QC samples and their concentrations and control limits. These parameters will be used by the system to calculate and display QC recoveries and threshold exceedances. A Network may have multiple sites or a single site depending on the agency and the number of PAMS sites they operate. The Network configuration also includes information about the site which is required to generate the EPA required Air Quality System (AQS) data file which is submitted for each site to incorporate the ambient data into the EPA AQS system.
Each Site also has unique information to identify it in the database. In addition to a specific
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References
EPA Technical Assistance Document (TAD)