Electronic Logbooks Software
The data acquisition computer at each site includes an electronic logbook using basic text-editing software such as notepad (or alternative cloud services such as Google Docs), and this log is crucial to operation, data validation, and accountability. The log records all site activities and instrument parameters affecting data including: Method changes, changes in calibration standards, instrument failures and corrective actions, physical site audits, remote access activities, computer configuration changes, disk and file maintenance, and all repair activities.
The logbook is archived nightly to insure integrity and allow data validators immediate access to important information regarding site specific activities affecting data acquisition.
Remote access software facilitates real-time inspection of the chromatographic data system via a secure broadband connection. With remote access software, the daily and hourly archives can be automatically transferred to another computer or a local host for advanced ozone prediction systems without operator intervention.
The Chromatographic Data System
The workhorse of each AutoGC is its chromatographic data system (CDS). The CDS collects and analyzes the results from the gas chromatograph outputting ASCII data files. The collection of data is managed by method files and sequence files. The AutoGC includes method files for ambient samples, blanks, calibration checks, and retention time checks. Sequence files automate the AutoGC by scheduling sequences of analyses.
Method files contain the specific analysis instructions such as compound names, retention times, retention windows, and calibration information for each compound. The method also specifies hardware settings such as oven temperature profiles, flame ionization detector temperatures, and flow rates. Each system will use pre-set methods for ambient samples, blanks, calibration checks, and retention time checks daily.
These methods require optimization to improve separation of the compounds being analyzed. In addition, the data output must conform to the needs of the the automation systems.
The Totalchrom Method Editor.
The EZChrom Method Editor.
Merlin EZ Sequence
Merlin EZ Sequence is a user-friendly interface for creating sequence files which are imported into the CDS. Sequence files are executed by the CDS and central to continuous automated operation of an AutoGC. Primarily, sequences allow the operator to configure the AutoGC for up to three weeks specifying the instrument method to be used for each sample. In this way the sequence files automate the regular scheduling of blanks, calibration checks, retention time checks, and data archiving. The sequence files also handle the automatic generation of unique hourly file names for each sample.
The TotalChrom Sequence Editor.
The EZChrom Sequence Editor.
Unique file names are of particular importance on an AutoGC. In a single month of operation the PerkinElmer Totalchrom system will generate over 1400 raw data files and the Agilent EZChrom system generates over 700. The AutoGC naming scheme for data files includes the site designation, column, sample type (i.e. sample, calibration, blank), and hourly timestamp. This allows files to be sorted using conventional file handling strategies and to group the files based on some degree of knowledge of their contents.
EZSequence also archives data hourly by compressing each hour’s data files, method file, and electronic logbook into a “single” file with a unique site and date code name in an archive (*.zip) format. Automating file archival is an important feature that allows the operator to focus on evaluating system performance and data validation, as well as reduces data losses from file handling mistakes.
Data Analysis & Reporting
EZ Quicklook polls the site daily and collects archived data. The data is then formatted into an Excel spreadsheet (*.xlsx) containing the hourly data from the last 24 hours including check standards and blanks. The report can then be emailed or uploaded to a cloud service, and is available by the start of the work day allowing operators to quickly catch system problems which might impact data and/or validation, and greatly reducing the need for data reprocessing.
Additionally, Orsat’s My AutoGC Xplorer (MAX) is a powerful online tool for data storage and analysis. Data loaded into MAX is automatically flagged if it is not within user specified control limits. Performance is thus evaluated easily and quickly thereby reducing data losses. Max allows reprocessing and manual flagging of data as needed. It also creates beautiful graphs of data as time series or scatter plots to explore complex relationships. Finally, MAX can generate output files for inclusion in the EPA Air Quaility System (AQS).
Standard Operating Procedures
Finally, Orsat creates site-specific Standard Operating Procedures (SOP) to aid the operator in the daily tasks he/she will be expected to perform. Important documents, details about subsystems, and resolutions to common problems for trouble shooting reference are included.
Installation & Configuration
Installation and configuration establishes a complete, fully functioning AutoGC system. By managing site-specific problems at the time of install, the system is brought online with all hardware and software integrated into a single, problem-free, long-term configuration.
Installation and setup takes only 3 to 5 days once all the necessary gases and power services are available. Each site will need broadband service if remote access and data transfer are required, as well as climate control to prevent overheating of the hardware.