Proposal for field sampling of plants and processing in the lab for environmental metabolic fingerprinting

Table 2 Extraction efficiency of repeated extractions.

	Peaks [%] at t_R= 0 - 14 min (mean ± sd)	Peaks [%] at t_R= 14 - 30 min (mean ± sd)	Peaks [%] at t_R= 30 - 38 min (mean ± sd)	Peaks [%] at t_R= 0 - 38 min (mean ± sd)
1. extraction	3.02 ± 0.59	77.64 ± 7.69	19.34 ± 8.17	41.61 ± 3.76
2. extraction	1.65 ± 0.46	53.47 ± 3.17	44.88 ± 3.20	64.91 ± 3.06
3. extraction	0 ± 0	34.68 ± 10.79	65.32 ± 10.79	72.04 ± 3.21
4. extraction	0.06 ± 2.86	28.82 ± 5.44	71.13 ± 5.50	87.75 ± 1.09
5. extraction	3.56 ± 2.48	31.50 ± 9.73	66.82 ± 12.38	94.93 ± 0.59
6. extraction	2.05 ± 1.13	30.68 ± 6.49	67.39 ± 4.86	98.07 ± 0.17
7. extraction	1.79 ± 0.68	29.54 ± 4.98	68.66 ± 3.59	100 ± 0

Percentage (mean ± standard deviation) of metabolites (peaks) detected in 7 subsequent extractions of Plantago lanceolata leaf material, extracted in 2:1 methanol:dichloromethane and analysed by HPLC. Number of replicates N = 5. Columns 1-3 show the percentages of peaks eluting between different retention times (t_R) within one extraction step. Columns 1-3 add up horizontally to 100% for each extraction step. In the fourth column the sum of all 150 integrated peaks of all 7 extractions was set as 100%. This column indicates the cumulative values from one extraction to another.