Compound characterization data — Gosset-Erard et al., 2026

Clarisse Gosset-Erard, Loïc Somont, Youssef El Husseini, Vincent Guérineau, Nhu Ngan Ha Nguyen, David Touboul, Rémy Ricoux, Jean-Yves Salpin, Salomé Poyer. “Resolving isomeric barriers of phosphatidylcholine in mixture by LC-MS/MS using copper(II) stabilization in the gas phase.” ChemRxiv (2026). https://doi.org/10.26434/chemrxiv.15007893/v1

Values presented only in spectra or images, including the color-coded detection matrix, were not transcribed

Phosphatidylcholine standards
ESI-MS, ligand screening, [PC+CuᴵᴵCl+ligand]⁺ formed with structural information from CID-MS/MS	2,2′-bipyridine: m/z 1011.5, normalized intensity 100 %; (1H-imidazol-2-yl)methanamine: m/z 952.5, 12 %; 1,10-phenanthroline: m/z 1035.5, 87 %; di(pyridin-2-yl)methanone: m/z 1039.5, 29 %; 5,5′-dimethyl-2,2′-bipyridine: m/z 1039.5, 43 %; 5,5′-bis(trifluoromethyl)-2,2′-bipyridine: m/z 1147.5, 58 %; [2,2′-bipyridine] 1-oxide: m/z 1027.5, 8 %; 1′-(l1-oxidaneyl)-1′l4-[2,2′-bipyridine] 1-oxide: m/z 1043.5, 4 %; pyridin-2-ylmethanamine: m/z 963.5, 67 %
ESI-MS, ligand screening, [PC+CuᴵᴵCl+ligand]⁺ formed without structural information from CID-MS/MS	[2,2′-bipyridine]-5,5′-dicarboxylic acid: m/z 1099.5; [2,2′-bipyridine]-5,5′-dicarbaldehyde: m/z 1067.5; 3,2′:6′,3″-terpyridine: m/z 1088.5; 4′-chloro-3,2′:6′,3″-terpyridine: m/z 1124.5; [3,2′:6′,3″-terpyridin]-4′-amine: m/z 1103.5; sodium 3-((pyridin-2-ylmethyl)amino)propanoate: m/z 1057.5
ESI-MS, ligand screening, [PC+CuᴵᴵCl+ligand]⁺ not formed	Picolinaldehyde: m/z 962.5; pyridin-3-ylmethanamine: m/z 963.5; nicotinic acid: m/z 978.5; nicotinamide: m/z 977.5; 1H-imidazole: m/z 923.5; 1H-imidazole-2-carbaldehyde: m/z 951.5; 1-(1H-imidazol-1-yl)ethan-1-one: m/z 965.6; L-histidine: m/z 1010.5; bis(pyridin-2-ylmethyl)amine: m/z 1054.5; di(pyridin-2-yl)amine: m/z 1026.5; benzamide: m/z 976.5; indole: m/z 972.5; 2-amino-1,9-dihydro-6H-purin-6-one: m/z 1006.5; 4,4′-dimethyl-2,2′-bipyridine: m/z 1039.5; 4,4′-dimethyl-2,2′-bipyridine: m/z 1071.5; 4′,5,5″-tri-tert-butyl-3,2′:6′,3″-terpyridine: m/z 1256.5; pyridine: m/z 934.5; ethyl 3-((pyridin-2-ylmethyl)amino)propanoate: m/z 1063.5; 2-((pyridin-2-ylmethyl)amino)ethan-1-ol: m/z 1023.5
ESI-MS, BPY and Cuᴵ	[BPY+Cuᴵ]⁺ was observed at m/z 218.9981
CID-MS/MS, PC 16:0/18:1(Δ9), [PC+CuᴵᴵCl+BPY]⁺	[CuCl+BPY]⁺ was observed at m/z 253.9663; [PC−H+Cuᴵ]⁺• was observed at m/z 821.4974; loss of the polar head, −183 Da, gave m/z 638.4316
CID-MS/MS, fatty-acyl-chain losses	[PC−FAₛₙ₁]⁺ and [PC−FAₛₙ₂]⁺ were observed at m/z 504.3449 and 478.3292; preferential sn-1 cleavage gave m/z 478.3310 for PC 18:1(Δ9)/16:0 and m/z 504.3438 for PC 16:0/18:1(Δ11); sn-1/sn-2 loss ratios ranged from 100/43 for PC 18:1(Δ9)/16:0 to 91/100 for PC 16:0/20:4(Δ14,11,8,5)
CID-MS/MS, double-bond diagnostic ions	Δ26 Da between m/z 708.3685 and 682.3519 for PC 18:1(Δ9)/16:0 and between m/z 736.3946 and 710.3788 for PC 16:0/18:1(Δ11) was diagnostic of double bonds at Δ9 and Δ11, respectively
CID-MS/MS, consecutive fragment ions	m/z 736.3998 and 722.3843 for PC 18:1(Δ9)/16:0; m/z 764.4267 and 750.4111 for PC 16:0/18:1(Δ11)
MALDI-TOF MS, PC 16:0/18:1(Δ11), [PC+CuᴵᴵCl+BPY]⁺	The complex ion formed with DCTB and DHAP matrices and was not observed with 1,5-DAN or DHB matrices

Commercial bovine liver total lipid extract
LC–ESI-CID-MS/MS, m/z [PC+CuᴵᴵCl+BPY]⁺ and annotated PC	985.5132: PC 16:0/16:1(Δ9), PC 16:0/16:1(Δ6); 987.5288: PC 16:0/16:0; 997.5132: PC 15:0/18:2(Δ8,Δ11); 999.5264: PC 16:0/17:1(Δ9), PC 15:0/18:1(Δ9); 1009.5132: PC 16:1(Δ9)/18:2(Δ9,Δ12), PC 16:0/18:3(Δ6,Δ9,Δ12), PC 16:0/18:3(Δ9,Δ12,Δ15); 1011.5288: PC 16:0/18:2(Δ9,Δ12), PC 16:1(Δ9)/18:1(Δ9); 1013.5445: PC 16:0/18:1(Δ9); 1015.5601: PC 18:0/16:0, PC 16:0/18:0; 1019.4975: PC 15:1/20:4(Δ5,Δ8,Δ11,Δ14); 1025.5446: PC 18:2(Δ9,Δ12)/17:0, PC 17:1/18:1(Δ9); 1027.5601: PC 17:0/18:1(Δ9), PC 18:0/17:1(Δ9); 1033.5132: PC 16:0/20:5(Δ2,Δ5,Δ8,Δ11,Δ14), PC 16:0/20:5(Δ5,Δ8,Δ11,Δ14,Δ17); 1035.5302: PC 16:0/20:4(Δ8,Δ11,Δ14,Δ17), PC 16:0/20:4(Δ5,Δ8,Δ11,Δ14); 1037.5446: PC 18:1(Δ9)/18:2(Δ9,Δ12), PC 16:0/20:3(Δ8,Δ11,Δ14); 1039.5601: PC 18:0/18:2(Δ9,Δ12); 1041.5758: PC 18:0/18:1(Δ9); 1049.5446: PC 17:0/20:4(Δ5,Δ8,Δ11,Δ14); 1051.5601: PC 17:0/20:3(Δ8,Δ11,Δ14); 1061.5446: PC16:0/22:5(Δ7,Δ10,Δ13,Δ16,Δ19), PC 18:1/20:4(Δ5,Δ8,Δ11,Δ14); 1063.5601: PC 18:0/20:4(Δ5,Δ8,Δ11,Δ14); 1065.5758: PC 18:0/20:3(Δ8,Δ11,Δ14); 1067.5914: PC 18:0/20:2(Δ11,Δ14); 1069.6071: PC 20:0/18:1(Δ9); 1089.5759: PC18:0/22:5(Δ7,Δ10,Δ13,Δ16,Δ19); 1091.5914: PC 18:0/22:4(Δ7,Δ10,Δ13,Δ16)

Commercial porcine brain total lipid extract
LC–ESI-CID-MS/MS, m/z [PC+CuᴵᴵCl+BPY]⁺ and annotated PC	931.454: PC 14:0/14:0; 959.4987: PC 16:0/14:0, PC 16:0/16:0; 985.5132: PC 16:1(Δ9)/16:0, PC 16:1(Δ6)/16:0, PC 16:0/16:1(Δ6); 987.5307: PC 16:0/16:0; 999.5264: PC 16:0/17:1(Δ9); 1011.5288: PC 16:1(Δ9)/18:1(Δ9), PC 16:0/18:2(Δ9,Δ12), PC 18:1(Δ9)/16:1(Δ9); 1015.5601: PC 18:0/16:0; 1027.5601: PC 17:0/18:1(Δ9), PC 18:0/17:1(Δ9); 1035.5288: PC 20:4(Δ5,Δ8,Δ11,Δ14)/16:0; 1037.5299: PC 20:3(Δ8,Δ11,Δ14)/16:0, PC 18:2(Δ9,Δ12)/18:1; 1041.5758: PC 18:0/18:1(Δ9); 1061.5446: PC 18:1/20:4(Δ5,Δ8,Δ11,Δ14), PC22:5(Δ4,Δ7,Δ10,Δ13,Δ16)/16:0; 1063.5601: PC 18:0/20:4(Δ5,Δ8,Δ11,Δ14), PC 16:0/22:4(Δ7,Δ10,Δ13,Δ16); 1069.6071: PC 18:1(Δ9)/20:0, PC 18:0/20:1(Δ11); 1091.5914: PC 18:0/22:4(Δ7,Δ10,Δ13,Δ16)

Commercial bovine heart total lipid extract
LC–ESI-CID-MS/MS, m/z [PC+CuᴵᴵCl+BPY]⁺ and annotated PC	959.4987: PC 16:0/14:0; 985.5132: PC 16:0/16:1(Δ9), PC 16:0/16:1(Δ11); 987.5307: PC 16:0/16:0, PC 18:0/14:0, PC 17:0/15:0; 997.5132: PC 15:0/18:2(Δ8,Δ11); 999.5264: PC 16:0/17:1(Δ9); 1009.5132: PC 16:1/18:2(Δ9,Δ12), PC 18:2(Δ9,Δ12)/16:1, PC 16:0/18:3(Δ9,Δ12,Δ15); 1011.5288: PC 16:0/18:2(Δ9,Δ12); 1013.5288: PC 16:0/18:1(Δ9); 1025.5446: PC 17:0/18:2(Δ9,Δ12), PC 17:0/18:2(Δ6,Δ9); 1027.5601: PC 17:0/18:1(Δ9); 1035.5288: PC 16:0/20:4(Δ5,Δ8,Δ11,Δ14); 1037.5299: PC 18:1(Δ9)/18:2(Δ9,Δ12), PC 16:0/20:3(Δ8,Δ11,Δ14); 1039.5601: PC 18:0/18:2(Δ8,Δ11), PC 18:1(Δ9)/18:1(Δ9), PC 18:0/18:2(Δ9,Δ12); 1041.5758: PC 18:0/18:1(Δ9); 1061.5446: PC 22:5(Δ7,Δ10,Δ13,Δ16,Δ19)/16:0; 1063.5601: PC 18:0/20:4(Δ5,Δ8,Δ11,Δ14); 1065.5758: PC 18:0/20:3(Δ8,Δ11,Δ14)

Commercial yeast (S. cerevisiae) total lipid extract
LC–ESI-CID-MS/MS, m/z [PC+CuᴵᴵCl+BPY]⁺ and annotated PC	929.4506: PC 16:1(Δ9)/12:0; 931.4662: PC 16:0/12:0; 955.4662: PC 16:1(Δ9)/14:1; 957.4819: PC 16:1(Δ9)/14:0, PC 14:0/16:1(Δ9), PC 18:1(Δ9)/12:0; 959.4975: PC 16:0/14:0, PC 18:0/12:0; 969.4819: PC 15:1(Δ10)/16:1; 971.4975: PC 15:0/16:1(Δ9); 983.4975: PC 16:1(Δ9)/16:1(Δ9); 985.5132: PC 16:0/16:1(Δ9); 997.5132: PC 17:1/16:1(Δ9); 999.5288: PC 15:0/18:1(Δ9); 1009.5132: PC 16:1/18:2(Δ9,Δ12); 1011.5288: PC 16:1(Δ9)/18:1(Δ9); 1013.5445: PC 16:0/18:1(Δ9), PC 18:0/16:1(Δ9); 1039.5601: PC 18:1(Δ9)/18:1(Δ9); 1041.5758: PC 18:0/18:1(Δ9)

Commercial soy polar lipid extract
LC–ESI-CID-MS/MS, m/z [PC+CuᴵᴵCl+BPY]⁺ and annotated PC	983.4975: PC 14:0/18:2(Δ9,Δ12); 985.5132: PC 16:0/16:1(Δ9); 897.5288: PC 16:0/16:0; 1009.5132: PC 16:0/18:3(Δ9,Δ12,Δ15), PC 18:2(Δ9,Δ12)/16:1; 1011.5288: PC 16:0/18:2(Δ9,Δ12); 1013.5445: PC 16:0/18:1(Δ9); 1023.5132: PC 18:2(Δ9,Δ12)/17:1(Δ9); 1025.5446: PC 17:0/18:2(Δ9,Δ12); 1033.5132: PC 18:3(Δ9,Δ12,Δ15)/18:2(Δ9,Δ12), PC 18:2(Δ9,Δ12)/PC 18:3(Δ9,Δ12,Δ15); 1035.5288: PC 18:2(Δ9,Δ12)/18:2(Δ9,Δ12); 1037.5446: PC 18:1(Δ9)/18:2(Δ9,Δ12), PC 18:2(Δ9,Δ12)/18:1(Δ9); 1039.5601: PC 18:1(Δ9)/18:1(Δ9), PC 18:0/18:2(Δ9,Δ12); 1041.5758: PC 18:0/18:1(Δ9); 1065.5758: PC 20:1(Δ11)/18:2(Δ9,Δ12); 1067.5914: PC 20:0/18:2(Δ9,Δ12); 1095.6227: PC 22:0/18:2(Δ9,Δ12)