Delta plus advantage stable isotope mass spectrometer

Leaf pinna samples were analysed for nitrogen and carbon content (%N and %C) and isotope discrimination (δ¹⁵N and δ¹³C) using mass spectrometry facilities in the Department of Biology at Colgate University.
Leaf samples were oven dried at 60 °C and ground into a powder using a Wiley Mill (Thomas Scientific Model 3383-L10) and were then weighed and rolled into tin capsules (5 × 9 mm Costech pressed tin capsules). Samples were then run through an elemental analyser, Costech Instruments Elemental Combustion System (Costech Analytical Technologies Inc. Valencia, CA, USA) in tandem with a Delta Plus Advantage Stable Isotope Mass Spectrometer (Thermo Fisher Scientific Inc. Waltham, MA, USA) at Colgate University. Leaf isotope values are expressed in delta notation (‰) relative to the standard PDB (Pee Dee Belemnite) and air, for C and N, respectively.

Leaflet samples were analysed for nitrogen and carbon content (C) and carbon isotope discrimination (δ¹³C) following Krieg et al. (2017) (link) using mass spectrometry facilities in the Department of Biology at Colgate University. Leaflet samples were oven dried at 65°C for 72 hours and ground into a powder using a Wiley Mill (Thomas Scientific Model 3383-L10). Ground samples were then weighed and rolled into tin capsules. Rolled samples were run through an elemental analyser, Costech Instruments Elemental Combustion System (Costech Analytical Technologies Inc. Valencia, CA, USA) in tandem with a Delta Plus Advantage Stable Isotope Mass Spectrometer (Thermo Fisher Scientific Inc. Waltham, MA, USA). Leaf isotope values are expressed in delta notation (‰) relative to the standard Pee Dee Belemnite and air, for C and N, respectively. Photosynthetic nitrogen-use efficiency (PNUE) was calculated by dividing leaf-level maximum photosynthetic rate by leaf nitrogen content.