sample metabolite derivative isotopologue area resolution 13C test 0 3179.092217 70000 13C test 1 813.5979041 70000 13C test 2 50000 70000 13C test 3 27000 70000 13C test 4 15000 70000 13C test 5 542.3658016 70000 13C test 6 78.26789778 70000 13C test 7 9.605558734 70000 13C test 8 1.051670856 70000 13C test 9 0 70000 13C test 10 0 70000