Optimising methods for the recovery and quantification of di- and tripeptides in soil

TY - JOUR

T1 - Optimising methods for the recovery and quantification of di- and tripeptides in soil

AU - Jamtgard, Sandra

AU - Robinson, Nicole

AU - Moritz, Thomas

AU - Colgrave, Michelle L.

AU - Schmidt, Susanne

PY - 2018/10/12

Y1 - 2018/10/12

N2 - Di- and tripeptides are intermediaries in the nitrogen cycle and are likely to have roles in the soil-microbe-plant continuum, but they have hitherto been difficult to measure in soils. To lay the base for future studies of oligopeptides in soil, we added 10 known di- and tripeptides with diverse chemical properties to forest and agricultural soils and then recovered the peptides by means of induced diffusive fluxes using microdialysis, a minimally-intrusive soil sampling technique. The concentration of the peptides recovered with the probes was 25-39% (relative recovery) of the concentration in the external solution, and followed the same trend as previously observed for amino acids, with smaller peptides (e.g. Gly-Gly) recovered at a higher rate than larger ones (e.g. Tyr-Phe). After derivatisation with AccQ-Tag™, a standard method for amino acids, peptides were analysed by ultra-high-pressure liquid chromatography-triple quadrupole mass spectrometry. Multiple reaction monitoring mass spectrometry was used to quantify specific peptides with a short run time of 15min and a detection limit of 0.01-0.02pmol injected (0.005-0.01pmol μL-1) for the different peptides. This methodology allowed successful analysis of all standard di- and tripeptides tested here. We conclude that microdialysis in combination with UHPLC-MS will allow measurement of plant-relevant fluxes of di- and tripeptides in undisturbed soil.

AB - Di- and tripeptides are intermediaries in the nitrogen cycle and are likely to have roles in the soil-microbe-plant continuum, but they have hitherto been difficult to measure in soils. To lay the base for future studies of oligopeptides in soil, we added 10 known di- and tripeptides with diverse chemical properties to forest and agricultural soils and then recovered the peptides by means of induced diffusive fluxes using microdialysis, a minimally-intrusive soil sampling technique. The concentration of the peptides recovered with the probes was 25-39% (relative recovery) of the concentration in the external solution, and followed the same trend as previously observed for amino acids, with smaller peptides (e.g. Gly-Gly) recovered at a higher rate than larger ones (e.g. Tyr-Phe). After derivatisation with AccQ-Tag™, a standard method for amino acids, peptides were analysed by ultra-high-pressure liquid chromatography-triple quadrupole mass spectrometry. Multiple reaction monitoring mass spectrometry was used to quantify specific peptides with a short run time of 15min and a detection limit of 0.01-0.02pmol injected (0.005-0.01pmol μL-1) for the different peptides. This methodology allowed successful analysis of all standard di- and tripeptides tested here. We conclude that microdialysis in combination with UHPLC-MS will allow measurement of plant-relevant fluxes of di- and tripeptides in undisturbed soil.

U2 - 10.1071/sr17279

DO - 10.1071/sr17279

M3 - Journal article

SN - 1838-675X

VL - 56

SP - 404

EP - 412

JO - Soil Research

JF - Soil Research

IS - 4

ER -