AS-D1 from Apollo SciTech

Presentation

The AS-D1 analyser, marketed by instrumentation company Apollo SciTech, is a device coupling liquid sample injectors, gas separators and simultaneous Picarro CRDS measurements of CO2 and 13Ccontent with accuracies of ±2 µmol/L for DIC and ±0.1‰ for δ13C. This coupling of instruments minimises sample handling (no gas separation) minimising contamination and sample loss.

The AS-D1 analyser enables simultaneous analysis of DIC and δ13C with precision and in small sample volumes of fresh or marine waters, in the millilitre range. Depending on the volume of sample available but the injection can range from 0.75 ml to 4 ml. At most, 3 samples are taken (injection by automatic syringe). The sample is injected into the reaction cell, surrounded by two volumes of H3PO4 (3% H3PO4 in 7% NaCl), where it is mixed. In the reaction cell, the sample + H3PO4 is mixed and the DIC is converted into CO2, which is sent via a flow of dry air (drierite – calcium sulphate filter) and CO2-free air (ascarite filter), into a Picarro analyser (CRDS). The analysis takes about 12 minutes per injection. The DIC is calibrated using certified seawater (Certified Reference Materials Laboratory, Professor Andrew G. Dickson, Scripps Institution of Oceanography, University of California, San Diego, and the δ13C calibration is currently being validated.