SPGAS™: SPecialty Gas Analysis Software

Knowledge-Based Innovation of Analytical andIndustrial Process InstrumentationVisit our web sites at: www.cicp.com & www.irgas.com 3825 Osuna RD NE Ste # 6 & 7Albuquerque, New Mexico 87109505-343-9500 Fax 509-479-2980E-mail: info@cicp.comSPGAS™: SPecialty Gas Analysis Software: (IAN-05-01)SPGAS™ is a user-friendly, turnkey FTIR software package designed specifically for theanalysis of gaseous constituents. While providing all of the control features of a standardFTIR software package for Bomem spectrometers, SPGAS™ also provides the ability for24/7/365 operation of the IRGAS™ analysis package. SPGAS™ is designed to savespectral files from each day of operations within it’s own automatically created directorystructure for ease of retrieval. It is designed to save these spectral files in a format thatallows spectral interchange with other FTIR software programs. The softwareautomatically generates and maintains running logs of results that can be graphicallydisplayed in real time and re-generated via an easily accomplished export to aspreadsheet program like Microsoft Excel™ .SPGAS™ does more than run ABB Bomem spectrometers. As seen in the Figure below,properly configured, the SPGAS™ software package can automatically run externalhardware in support of the FTIR spectrometer. This allows SPGAS™ to collecttemperature and pressure data and modify the calibration information to compensate forsmall changes in the gas cell temperature or pressure. SPGAS™ can also control valvesand external events and track which gas stream is being sampled at any point in time.Figure 1: Control Capabilities of SPGAS™The valve information is stored in the generated log file. Furthermore, SPGAS™ canprovide external event control for such things as analog-out reporting, valve events, andalarm control. One of the more interesting aspects of SPGAS™ is the use of automated mirrors that canbe installed in CICP’s gas cells. With automated mirrors, SPGAS™ software can run theSpectraStream™ Module (U.S. Patent # 6,748,334) to rapidly collect background spectraand sample spectra one after the other. This allows the SPGAS™ software to update thebackground spectra to compensate for small changes in the background levels of suchconstituents as CO2 and moisture. This provides a more accurate baseline subtractionroutine which results in more accurate spectral modeling and more accurate results. Theother advantage of running SpectraStream™ is the ability to identify even small changesin the sample spectra over the background spectra and report these changes to theoperator. Figure 2: SPGAS™ Frame with SpectraStream™ OperatingA further advantage of automated mirrors is the ability to collect background spectrawithout having to clear the gas cell. This allows the gas cell to remain in operationcontinuously without having to be purged in order to collect an in-cell background spectra.This reduces the complexity of the system by eliminating the purge gas and the valvesrequired to control the purge gas. It also allows the IRGAS™ system to operate in aremote location and in a completely automated manner without user intervention.The SPGAS™ software package can be calibrated in a number of manners. For somegases, the HITRAN data base can be used as a synthetic calibration prior to shipping thesystem to the customer site. A partial list of HITRAN gases can be found in Table 1below. For non-HITRAN gases, CIC Photonics will pre-calibrate the system for thosegases requested for a small fee. For the user that has access to calibrated levels of thosegases, CICP’s Qmax™ software provides an easy and efficient means of calibrating thesystem. Using Qmax™, the end-user can take a collected spectra at a knownconcentration and quickly identify the appropriate spectral bands for use in the calibration.Having set up the calibration, the user can then collect multiple levels of calibrationspectra and append them to the calibration file for that particular gaseous species. Theuser repeats the process for whatever number of gases desired. These calibration filesare then combined in a single unique calibration data set that can be used for futureanalysis. H2O CO NO NO2 CO2 HF HCl HBr NH3 SO2 H2CO HCN C2H6 C2H4 H2S PH3Table 1: Partial List of HITRAN gasesSPGAS™ uses a weighted average multi-band Classical Least Squares (CLS) algorithmto provide accurate quantitation. This approach provides numerous advantages oversimpler software packages. For example. SPGAS™ takes into account small changes inthe baseline which may affect the overall peak shape. It also takes into accountoverlapping spectral bands which may interfere with the proper quantitation of analytes inthe gas stream. Weighting of the individual spectral bands provides the ability to minimizebands where the levels of interference are high or the absorbance of the species hasgone non-linear, while at the same time emphasizing the bands that are a good matchwith the calibrated spectra. Quantitation data are presented for all of the calibratedspecies in the calibration table along with information about how the quantitation bandswere weighted and with the residual information for each calibrated compound. Thisprovides the user a rapid and easily understood means of evaluating the data.These are some of the features that combine to make SPGAS™ the most powerful,simple-to-use, FTIR gas analysis package on the market today. For more informationabout SPGAS™ or any other CIC Photonics product, please do not hesitate to contact usat the address above.