TDLAS & QF Analyzers

TDLAS & QF Analyzers

TDLAS (tunable diode laser absorption spectroscopy) and QF (quenched fluorescence) analyzers are optical gas analysis instruments engineered for fast, selective measurement of critical analytes in process gas streams. Typical target measurements include H2O, H2S, and CO2 by TDLAS and oxygen from trace to percent levels by QF, enabling continuous quality and process control in demanding gas applications.

TDLAS uses laser absorption spectroscopy, tuning a diode laser across a specific absorption line of the analyte to determine concentration with high selectivity. Because the measurement is optical, it can be implemented with zero contact between the process gas sample and sensitive analyzer components, protecting the measurement path from corrosion and contamination. QF analyzers use fluorescence quenching to quantify oxygen with strong performance across wide ranges, supporting applications where oxygen control is required from trace levels through percent measurement. In natural gas service, QF oxygen measurement is valued for speed, stability, and resistance to interference from H2S and other contaminants.

These techniques have reshaped online gas analysis by pairing laboratory-like specificity with industrial robustness. Fast response supports immediate detection of contamination or upsets, while stable, repeatable measurements improve control performance and product specification assurance. Reduced maintenance demand, minimal recalibration requirements, and strong immunity to common interferents translate into higher uptime and lower total cost of ownership.

Practical implementation is typically available in compact, field- or panel-mounted configurations suitable for pipeline stations, processing plants, and hazardous-area environments. Standard digital interfaces support integration with PLC/DCS platforms, and diagnostic functions help confirm measurement integrity over long service intervals. The non-contact nature of the measurement also reduces the burden on sample handling components compared with traditional wet-chemistry or sensor-based approaches.

Typical applications include moisture and acid-gas monitoring in natural gas transmission and processing, LNG plants, refinery and petrochemical gas streams, and high-confidence oxygen measurement in gas applications such as dehydration and treating units, compressor stations, and custody-transfer-related quality verification where speed, stability, and low maintenance are essential.

At Eastern Controls, We are proud to be the exclusive authorized sales and service representative for Endress+Hauser.