To better assist our customers to meet the requirements of the Instrumental Methods for testing 3A, 6C, 7E, 10, and 20, we are providing a summary of interferences for certain Thermo Fisher Scientific analyzers.
The information contained in the tables pertains to the “make” of analyzers under the name of: Thermo Electron Corporation, Thermo Environmental Instruments and Thermo Scientific. The gas analyzer models are: 42iQLS and 42iQHL for NO, NO2, NOx; 43iQHL for SO2; 48iQ for CO and 410iQ for CO2. The specific pollutant detection and analytical technology for each of the above listed specific models have remained the same for various series of analyzers manufactured over the past years. Therefore, the interference test results shown for the iQ Series analyzers in this document would produce essentially the same results for iSeries and earlier series of these models.
Thermo Scientific 42iQLS & 42iQHL NO-NO2-NOX Analyzer
Potential Interferent Gas Responses
| Potential Interferent | 42iQLS | |||
| Test Gas | Concentration | As ppm NO | As ppm NO2 | As ppm NOx |
| CO2 | 5% | -0.01 | -0.01 | -0.02 |
| CO2 | 15% | -0.02 | -0.01 | -0.03 |
| H2O | 3% | -0.04 | 0.02 | -0.02 |
| N2O | 47 ppm | 0.03 | -0.01 | 0.02 |
| CO | 50 ppm | 0.03 | 0.00 | 0.03 |
| SO2 | 27 ppm | 0.00
| -0.01 | -0.01 |
| CH4 | 50 ppm | 0.01 | 0.01 | 0.00 |
| HCl | 20 ppm | 0.02 | 0.00 | 0.02 |
| NH3 | 9 ppm | 0.00 | 0.00 | -0.01 |
| Sum of Responses | 0.17 | 0.07 | 0.16 | |
| Span Value | 160 | 128 | 160 | |
| % of Calibration Span | 0.11% | 0.06% | 0.10% | |
| Potential Interferent | 42iQHL | |||
| Test Gas | Concentration | As ppm NO | As ppm NO2 | As ppm NOx |
| CO2 | 5% | 0.00 | 0.00 | 0.00 |
| CO2 | 15% | 0.00 | 0.00 | 0.00 |
| H2O | 3% | 0.03 | -0.01 | 0.01 |
| N2O | 47 ppm | 0.03 | 0.00 | 0.03 |
| CO | 50 ppm | 0.00 | 0.02 | 0.02 |
| SO2 | 27 ppm | 0.00 | 0.00 | 0.00 |
| CH4 | 50 ppm | 0.00 | 0.00 | 0.00 |
| HCl | 20 ppm | -0.01 | 0.09 | 0.08 |
| NH31 | 9 ppm | 0.01 | 6.61 | 6.68 |
| Sum of Responses | 0.08 | 0.12 | 0.15 | |
Span Value | 160 | 128 | 160 | |
| % of Calibration Span | 0.05% | 0.09% | 0.09% | |
Note: Acceptance criterion based on Section 13.4 of Method 7E, states that the sum of the responses must not be greater than 2.5% of the analyzer calibration value.
1NH3 interferent results shown for the 42iQHL was not used in the calculation of the interferent response check because it is a known interferent with an approximate 1 ppm to 1 ppm positive bias in analyzers using stainless steel NO2 to NO converters. Thermo Scientific recommends that NOx analyzers with stainless steel NO2 to NO converters must use a NH3 scrubber when testing sources with potential NH3 in the flue gas.
Thermo Scientific 43iQHL SO2 Analyzer
Potential Interferent Gas Responses
| Potential Interferent | 43iQHL | |
| Test Gas | Concentration | As ppm SO2 |
| CO2 | 5% | 0.0 |
| CO2 | 15% | 0.1 |
| H2O | 3% | 0.0 |
| NO | 10 ppm | 0.2 |
| NO2 | 38 ppm | 0.0 |
| N2O | 47 ppm | 0.1 |
| CO | 50 ppm | 0.1 |
| SO2 | 100 ppm | 100.0 |
| CH4 | 50 ppm | 0.0 |
| HCl | 160 ppm | 0.0 |
| NH3 | 9 ppm | 0.0 |
| Sum of Responses | 0.450 | |
| Span Value | 100 | |
| % of Calibration Span | 0.45% | |
Note: Acceptance criterion based on Section 13.4 of Method 7E, states that the sum of the responses must not be greater than 2.5% of the analyzer calibration value.
Thermo Scientific 48iQ CO Analyzer
Potential Interferent Gas Responses
| Potential Interferent | 48iQ | |
| Test Gas | Concentration | As ppm CO |
| CO2 | 5% | -0.2 |
| CO2 | 15% | -0.5 |
| H2O | 3% | 0.2 |
| NO | 10 ppm | 0.1 |
| NO2 | 38 ppm | -0.1 |
| N2O | 10 ppm | -0.1 |
| CO | 507 ppm | 508.0 |
| SO2 | 27 ppm | -0.1 |
| CH4 | 50 ppm | -0.1 |
| HCl | 160 ppm | 0.0 |
| NH3 | 9 ppm | -0.1 |
| Sum of Responses | 1.6 | |
| Span Value | 507 | |
| % of Calibration Span | 0.32% | |
Note: Acceptance criterion based on Section 13.4 of Method 7E, states that the sum of the responses must not be greater than 2.5% of the analyzer calibration value.
Thermo Scientific 410iQHL CO2 Analyzer
Potential Interferent Gas Responses
| Potential Interferent | 410iQHL | |
| Test Gas | Concentration | As % CO2 |
| CO2 | 5% | 4.8 |
| CO2 | 15% | 15.0 |
| H2O | 3% | 0.0 |
| NO | 10 ppm | 0.0 |
| NO2 | 38 ppm | 0.0 |
| N2O | 10 ppm | 0.0 |
| CO | 507 ppm | 0.0 |
| SO2 | 27 ppm | 0.0 |
| CH4 | 50 ppm | 0.0 |
| HCl | 160 ppm | 0.0 |
| NH3 | 9 ppm | 0.0 |
| Sum of Responses | 0.02 | |
| Span Value | 15 | |
| % of Calibration Span | 0.12% | |
Note: Acceptance criterion based on Section 13.4 of Method 7E, states that the sum of the responses must not be greater than 2.5% of the analyzer calibration value.