DETECTORS Catalytic Combustion Detector - CCD CCD Detector and protective cap (cap is removed prior to installation) The Catalytic Combustion Detector responds to all hydrocarbons with the selectivity of an FID and the sensitivity of a TCD. The entire detector’s diameter is merely one centimeter. Its sensor element consists of a tiny coil of platinum wire embedded in a catalytic ceramic bead. Each CCD detector has a pair of sensor elements. The sensors are housed in high-grade, flameproof nylon, and protectively capped with a fine steel mesh. In SRI GCs, the CCD detector is mounted on the wall of the Column Oven in a brass housing, as shown in the top left picture. The analytical column residing in the Column Oven is connected to the detector through the oven wall; the example shown at bottom left is an SRI Gas-lessTM Educational GC featuring a CCD detector and a 1m (3’) Hayesep-D packed column. The CCD detector is especially suited for gasless operation because it can operate on ambient air, requiring no high pressure cylinder gases such as hydrogen or helium. In the GC system pictured at left, a built-in air compressor supplies the carrier gas for the CCD. The CCD detector can also be used as a hydrocarbon monitor in non-chromatographic applications where the CCD senses the total hydrocarbon content of a flowing air stream, or as a hydrogen/hydrocarbon leak detector

DETECTORS Catalytic Combustion Detector - CCD Theory of Operation Top View of CCD Detector The CCD sensor elements are the tiniest and most important part of the detector. Each CCD detector contains two sensor elements, but uses only one at a time. A catalytic combustion sensor consists of a coil of platinum wire around an alumina core surrounded by noble metal catalysts. Each sensor is suspended between a pair of nickel pins. The detector is shipped with a protective nylon cap topped with steel mesh, but is installed on a SRI GC without it. During a chromatogaphic run, a 150 milliamp current...

DETECTORS Catalytic Combustion Detector - CCD Expected Performance CCD Detector Noise Run Column = 1m Hayesep D Flow = 37mL/min Isothermal Temperature Program: Initial Hold Ramp Final 80oC 15.00 0.00 80oC Noise level is approximately 50µV from peak to peak Factory Test Run of a Gas-lessTM Educational GC System Column = 1m Hayesep D Flow = 37mL/min Sample = 1µL 1000ppm Methanol/Acetone mix; direct injection Isothermal Temperature Program: Initial Temp Hold Ramp Final Temp 130oC 10.00 0.00 130oC RESULTS: Component Methanol Acetone Negative water peak