Common background ions in positive mode ESI LC-MS

Electrospray mass spectra almost always contain background ions that originate from solvents, buffers, plasticizers, detergents, and other laboratory materials rather than from the sample. Knowing the common ones helps you recognize contamination and avoid chasing peaks that will never match a peptide. The table below lists frequently observed singly charged background ions with their monoisotopic mass, formula, and likely origin. Another good resource is the Contamination Search Tools at the University of Leiden.

Mono mass [M+H]+ Formula Compound Possible origin and comments
33.033491 CH3OH Methanol Acetonitrile, solvent
42.033825 CH3CN ACN Acetonitrile, solvent
59.060374 CH3CN ACN Acetonitrile, solvent
63.044056 [C2H4O]nH2O PEG Polyethylene glycol, ubiquitous polyether
64.015769 CH3CN ACN Acetonitrile, solvent
65.059706 CH3OH Methanol Methanol, solvent
74.060040 (CH3CN)n(CH3OH)m ACN/Methanol ESI solvents
74.060040 C3H7NO DMF Dimethyl formamide, solvent
77.059706 [C3H6O]nH2O PPG Polypropylene glycol, ubiquitous polyether
79.021212 C2H6OS DMSO Dimethylsulfoxide, solvent
83.060374 CH3CN ACN ESI solvents
85.026000 [C2H4O]nH2O PEG Polyethylene glycol, ubiquitous polyether
85.058868 C2D6OS d6-DMSO d6-Dimethylsulfoxide, solvent
88.039305 (CH3CN)n(HCOOH)m ACN/FA ESI solvents
96.041984 (CH3CN)n(CH3OH)m ACN/Methanol ESI solvents
99.041650 [C3H6O]nH2O PPG Polypropylene glycol, ubiquitous polyether
100.075690 C5H10NO NMP N-methyl 2-pyrrolidone; solvent, floor stripper
100.999937 [C2H4O]nH2O PEG Polyethylene glycol, ubiquitous polyether
101.003156 C2H6OS DMSO Dimethylsulfoxide, solvent
101.080836 [MeOH]n[H2O]m Methanol/Water ESI solvents
102.054955 (CH3CN)n(CH3COOH)m ACN/AA ESI solvents
102.127725 C6H15N TEA Triethylamine, buffer
103.955601 C2H3N ACN Acetonitrile, solvent
104.992294 C2H3O2Na Sodium acetate ESI solvents
105.042318 C2H3N ACN Acetonitrile, solvent
105.953794 C2H3N ACN Acetonitrile, solvent
107.070271 [C2H4O]nH2O PEG Polyethylene glycol, ubiquitous polyether
115.015587 [C3H6O]nH2O PPG Polypropylene glycol, ubiquitous polyether
115.086589 (CH3CN)n(C3H7NO)m ACN/DMF ACN/Dimethylformamide, solvent
120.047761 C2H6OS DMSO Dimethylsulfoxide, solvent
122.081170 C4H11NO3 TRIS TRIS, buffer
123.062780 [MeOH]n[H2O]m Methanol/Water ESI solvents
123.091674 C7H10N2 DMAP Dimethylaminopyridine, solvent
124.036899 (CH3CN)n(CH3COOH)m ACN/AA ESI solvents
129.052215 [C2H4O]nH2O PEG Polyethylene glycol, ubiquitous polyether
130.159025 C8H19N DIPEA Diisopropylethylamine, solvent
132.904901 Cs Cs-133 Cesium, from Cesium Iodide used as calibrant
133.107051 [MeOH]n[H2O]m Methanol/Water ESI solvents
135.101571 [C3H6O]nH2O PPG Polypropylene glycol, ubiquitous polyether
137.074310 C2H6OS DMSO Dimethylsulfoxide, solvent
142.029705 C2H6OS DMSO Dimethylsulfoxide, solvent
144.174675 C9H21N TPA Tripropylamine, solvent
144.982150 CH3CN ACN Acetonitrile, solvent, together with m/z 147
145.026152 [C2H4O]nH2O PEG Polyethylene glycol, ubiquitous polyether
146.068867 CH3CN ACN Acetonitrile, solvent
146.980343 CH3CN ACN Acetonitrile, solvent, together with m/z 145
147.112804 (CH3CN)n(CH3OH)m ACN/Methanol ESI solvents
149.023321 C8H4O3 Pthalic Anhydride Fragment ion originating from phthalate esters
150.127725 C10H15N Phenyldiethylamine Solvent
151.096486 [C2H4O]nH2O PEG Polyethylene glycol, ubiquitous polyether
153.138624 C9H16N2 DBU 1,8-Diazabicyclo[5.4.0]undec-7-ene
155.088995 [MeOH]n[H2O]m Methanol/Water ESI solvents
157.035148 C2H6OS DMSO Dimethylsulfoxide, solvent
157.083515 [C3H6O]nH2O PPG Polypropylene glycol, ubiquitous polyether
158.964029 C2F3O2Na NaTFA Sodium trifluoroacetate, salt
163.038971 C10H10O4 Dimethyl phthalate Phthalate esters, plasticizer
163.132871 C8H18O3 DGBE Diethylene glycol monobutyl ether, scintillation cocktail
167.033886 C8H6O4 Phthalic acid Dioctyl phthalate
169.094748 (CH3CN)n(CH3OH)m Acetonitrile/Methanol ESI solvents
169.110460 C2D6OS d6-DMSO d6-Dimethylsulfoxide, solvent
171.005265 C8H4O3 Phthalic anhydride from phthalate esters, plasticizer
172.039305 C10H7NO3 4-HCCA matrix compound
173.057452 [C3H6O]nH2O PPG Polypropylene glycol, ubiquitous polyether
173.078430 [C2H4O]nH2O PEG Polyethylene glycol, ubiquitous polyether
179.017092 C2H6OS DMSO Dimethylsulfoxide, solvent
181.122306 C11H16O2 BHA Butylated hydroxyanisole, antioxidant additives
183.080441 C13H10O DPK Diphenyl ketone
183.143831 [MeOH]n[H2O]m Methanol/Water ESI solvents
185.114815 C8H18O3 GE glycol ether
186.221625 C12H27N TBA Tributylamine, solvent
189.052367 [C2H4O]nH2O PEG Polyethylene glycol, ubiquitous polyether
190.049870 C10H7NO3 4-HCCA matrix compound
193.143436 [C3H6O]nH2O PPG Polypropylene glycol, ubiquitous polyether
195.065186 C6H4[COOCH3]2 DMP Dimethyl phthalate, Phthalate esters, plasticizer
195.122701 [C2H4O]nH2O PEG Polyethylene glycol, ubiquitous polyether
203.104250 C11H16O2 BHA Butylated hydroxyanisole, antioxidant additives
204.078096 C8H4O3 Phthalic anhydride Plasticiser
205.125775 [MeOH]n[H2O]m Methanol/Water ESI solvents
209 na Pthalic Anhydride Phthalates Plastics, Nalgene bottles, tubing
212.031814 C10H7NO3 4-HCCA matrix compound, sodiated
214.089626 C10H15NO2S n-BBS n-butyl benzenesulfonamide, plasticizer
215.125380 [C3H6O]nH2O PPG Polypropylene glycol, ubiquitous polyether
217.104645 [C2H4O]nH2O PEG Polyethylene glycol, ubiquitous polyether
221.189991 C15H24O BTH Butylated hydroxytoluene, Antioxidant
223.0965 C6H4[COOC2H5]2 DEP Diethyl phthalate
225.196139 C13H24N2O DCU N,N’-Dicyclohexylurea
228.005751 C10H7NO3 4-HCCA matrix compound, potassiated
231.099317 [C3H6O]nH2O PPG Polypropylene glycol, ubiquitous polyether
231.116175 C10H15NO2S n-BBS n-butyl benzenesulfonamide, plasticizer
233.078582 [C2H4O]nH2O PEG Polyethylene glycol, ubiquitous polyether
235.049100 na DMSO na
236.071570 C10H15NO2S n-BBS n-butyl benzenesulfonamide, plasticizer
237 na Pthalic Anhydride Plasticizers, Tygon tubing, solvents
239.148916 [C2H4O]nH2O PEG Polyethylene glycol, ubiquitous polyether
239.224852 C6H15N TEA.HCl Triethylamine-hydrochloride, buffer
241.221902 C6H15N TEA.HCl Triethylamine-hydrochloride, buffer
242.284225 C16H36N TBA Tetrabutylammonium, buffer
243.116826 C19H15 Trityl cation Trityl cation, [Ph3C]+
243.171935 C15H24O BTH Butylated hytroxytoluene, Antioxidant additives
247.0965 C6H4(COOCH2CH=CH2)2 DAP Diallyl phthalate
251.1278 C6H4(COO(CH2)2CH3)2 DPP Di-n-propyl phthalate
251.185301 [C3H6O]nH2O PPG Polypropylene glycol, ubiquitous polyether
251.200556 [C14H22O][C2H4O]n Triton X-100, X-114, X-405, or X-45 Detergents
255 na Pthalic Anhydride na
257.031028 C2H6OS DMSO Dimethylsulfoxide, solvent
261.130860 [C2H4O]nH2O PEG Polyethylene glycol, ubiquitous polyether
265.216206 [C15H24O][C2H4O]n Triton 101 Detergents
267.171973 C12H27O4P TBP Tributylphosphate
273.127391 C20H17O MMT Monomethoxytrityl cation
273.167245 [C3H6O]nH2O PPG Polypropylene glycol, ubiquitous polyether
273.182500 [C14H22O][C2H4O]n Triton X-100, X-114, X-405, or X-45 Detergents
277.104797 [C2H4O]nH2O PEG Polyethylene glycol, ubiquitous polyether
279.093328 C18H15OP TPO Triphenylphosphine oxide
279.159086 C6H4(COO(CH2)3CH3)2 DBP Dibutylphthalate, Plasticiser, phthalate ester
279.1591 C6H4(COOCH2CH(CH3)2)2 DIBP Diisobutylphthalate
279.229450 [C14H28O][C2H4O]n Triton, reduced X-100R, X-114R, X-405R, or X-45R Detergents
282.279140 C18H35NO Oleamide Slip agent in polyethylene films
283.175131 [C2H4O]nH2O PEG Polyethylene glycol, ubiquitous polyether
284.294790 C18H37NO Stearamide Slip agent in polyethylene films
287.198150 [C15H24O][C2H4O]n Triton 101 Detergents
288.253320 C16H33NO3 n,n-DDA n,n-bis(2-hydroxyethyl) dodecanamide, anti-static agent
289.141182 [C3H6O]nH2O PPG Polypropylene glycol, ubiquitous polyether
293.245100 [C15H30O][C2H4O]n Triton, reduced 101R Detergents
295.226771 [C14H22O][C2H4O]n Triton X-100, X-114, X-405, or X-45 Detergents
301.141030 C16H22O4 Dibutylphthalate Dibutylphthalate, plasticizer
304.261084 C18H35NO Oleamide Slip agent in polyethylene films
305.157075 [C2H4O]nH2O PEG Polyethylene glycol, ubiquitous polyether
305.1747 CH3(CH2)3OOCC6H4COOC6H11 BCP Butylcyclohexylphthalate
306.276734 C18H37NO Stearamide Slip agent in polyethylene films
307.1904 C6H4(COO(CH2)4CH3)2 DNPP Di-n-pentylphthalate
309.227166 [C3H6O]nH2O PPG Polypropylene glycol, ubiquitous polyether
309.242421 [C15H24O][C2H4O]n Triton 101 Detergents
313.1434 C19H20O4 BBP Butyl benzyl phthalate
315.252986 C18H34O4 DBS Dibutyl sebacate, plasticizer
317.114967 C16H22O4 Dibutylphthalate Dibutylphthalate, plasticizer
317.208715 [C14H22O][C2H4O]n Triton X-100, X-114, X-405, or X-45 Detergents
321.131012 [C2H4O]nH2O PEG Polyethylene glycol, ubiquitous polyether
323.255665 [C14H28O][C2H4O]n Triton, reduced X-100R, X-114R, X-405R, or X-45R Detergents
325.258466 C8H18O3 DGBE Diethylene glycol monobutyl ether, scintillation cocktail
327.078073 C18H15O4P TPP Triphenyl phosphate, flame retardant in plastics
327.201346 [C2H4O]nH2O PEG Polyethylene glycol, ubiquitous polyether
331.1904 C6H4(COOC6H11)2 DCP Dicyclohexyl phthalate
331.209110 [C3H6O]nH2O PPG Polypropylene glycol, ubiquitous polyether
331.224365 [C15H24O][C2H4O]n Triton 101 Detergents
335.2217 C20H30O4 DIHxP Diisohexyl phthalate
335.2217 C20H30O4 DNHP Di-n-hexyl phthalate
337.118405 C13H28O2Sn Tributyl tin formate Tributyl tin formate, catalyst
337.271315 [C15H30O][C2H4O]n Triton, reduced 101R Detergents
338.341740 C22H43NO Erucamide Erucamide, (Cis-13-docosenoic amide)
339.252986 [C14H22O][C2H4O]n Triton X-100, X-114, X-405, or X-45 Detergents
347.183047 [C3H6O]nH2O PPG Polypropylene glycol, ubiquitous polyether
349.183290 [C2H4O]nH2O PEG Polyethylene glycol, ubiquitous polyether
353.268636 [C15H24O][C2H4O]n Triton 101 Detergents
355.069936 [C2H6SiO]5 Polysiloxane Polysiloxane, (neutral methane loss from m/z 371)
360.323684 C22H43NO Erucamide Erucamide, (Cis-13-docosenoic amide)
361.234930 [C14H22O][C2H4O]n Triton X-100, X-114, X-405, or X-45 Detergents
363.253 C22H34O4 BDP Butyl decyl phthalate
363.253 C22H34O4 DIHpP Diisoheptyl phthalate
365.157227 [C2H4O]nH2O PEG Polyethylene glycol, ubiquitous polyether
367.269031 [C3H6O]nH2O PPG Polypropylene glycol, ubiquitous polyether
367.281880 [C14H28O][C2H4O]n Triton, reduced X-100R, X-114R, X-405R, or X-45R Detergents
368.425075 C25H54NCl BTAC-228 Behentrimonium chloride, personal care product additive
371.101236 [C2H6SiO]5 Polysiloxane Polysiloxane, followed by m/z 388
371.227561 [C2H4O]nH2O PEG Polyethylene glycol, ubiquitous polyether
371.315586 C22H42O4 DEHA Bis(2-ethylhexyl) adipate, plasticizer
371.315586 C22H42O4 DOA Dioctyl adipate, plasticizer
375.250580 [C15H24O][C2H4O]n Triton 101 Detergents
379.092464 C10H7NO3 4-HCCA matrix cluster, dimer
381.297530 [C15H30O][C2H4O]n Triton, reduced 101R Detergents
383.279201 [C14H22O][C2H4O]n Triton X-100, X-114, X-405, or X-45 Detergents
388.127785 [C2H6SiO]5 Polysiloxane Polysiloxane, (see m/z 371)
389.250975 [C3H6O]nH2O PPG Polypropylene glycol, ubiquitous polyether
391.284286 C6H4(COO(CH2)5CH(CH3)2)2 DIOP Diisooctyl phthalate, plasticiser
391.2843 C6H4(COOCH2CH(C2H5)(CH2)3CH3)2 DEHP, DOP Di(2-ethylhexyl) phthalate
391.2843 C6H4(COO(CH2)7CH3)2 DNOP Di(n-octyl) phthalate
393.209505 [C2H4O]nH2O PEG Polyethylene glycol, ubiquitous polyether
397.294851 [C15H24O][C2H4O]n Triton 101 Detergents
405.224912 [C3H6O]nH2O PPG Polypropylene glycol, ubiquitous polyether
405.261145 [C14H22O][C2H4O]n Triton X-100, X-114, X-405, or X-45 Detergents
409.183442 [C2H4O]nH2O PEG Polyethylene glycol, ubiquitous polyether
411.308095 [C14H28O][C2H4O]n Triton, reduced X-100R, X-114R, X-405R, or X-45R Detergents
413.266230 C24H38O4 Diisooctyl phthalate Diisooctyl phthalate, plasticiser
415.253776 [C2H4O]nH2O PEG Polyethylene glycol, ubiquitous polyether
419.276795 [C15H24O][C2H4O]n Triton 101 Detergents
419.3156 C6H4(COO(CH2)6CH(CH3)2)2 DINP Diisononyl phthalate
419.3156 CH3(CH2)7OOCC6H4COO(CH2)9CH3 ODP n-Octyl n-decyl phthalate
425.310896 [C3H6O]nH2O PPG Polypropylene glycol, ubiquitous polyether
425.323745 [C15H30O][C2H4O]n Triton, reduced 101R Detergents
427.305416 [C14H22O][C2H4O]n Triton X-100, X-114, X-405, or X-45 Detergents
429.088728 [C2H6SiO]6 Polysiloxane Polysiloxane, (neutral methane loss from m/z 445)
429.240167 C24H38O4 Diisooctyl phthalate Diisooctyl phthalate, plasticiser
437.235720 [C2H4O]nH2O PEG Polyethylene glycol, ubiquitous polyether
441.014789 C10H7NO3 4-HCCA matrix-copper adduct, together with m/z 443
441.321066 [C15H24O][C2H4O]n Triton 101 Detergents
443.012982 C10H7NO3 4-HCCA matrix-copper adduct, together with m/z 443
445.120028 [C2H6SiO]6 Polysiloxane Polysiloxane, followed by m/z 462
447.292840 [C3H6O]nH2O PPG Polypropylene glycol, ubiquitous polyether
447.3469 C6H4(COO(CH2)7CH(CH3)2)2 DIDP Diisodecyl phthalate
449.287360 [C14H22O][C2H4O]n Triton X-100, X-114, X-405, or X-45 Detergents
449.385002 C13H24N2O DCU N,N’-Dicyclohexylurea
453.209657 [C2H4O]nH2O PEG Polyethylene glycol, ubiquitous polyether
453.343532 C24H44N4O4 nylon Cyclic oligomer of polyamide 66
454.292779 C24H38O4 Diisooctyl phthalate Diisooctyl phthalate, plasticiser, high conc formic acid
455.334310 [C14H28O][C2H4O]n Triton, reduced X-100R, X-114R, X-405R, or X-45R Detergents
459.279991 [C2H4O]nH2O PEG Polyethylene glycol, ubiquitous polyether
462.146577 [C2H6SiO]6 Polysiloxane Polysiloxane (see m/z 445)
463.266777 [C3H6O]nH2O PPG Polypropylene glycol, ubiquitous polyether
463.303010 [C15H24O][C2H4O]n Triton 101 Detergents
469.349960 [C15H30O][C2H4O]n Triton, reduced 101R Detergents
471.331631 [C14H22O][C2H4O]n Triton X-100, X-114, X-405, or X-45 Detergents
475.3782 C6H4(COO(CH2)8CH(CH3)2)2 DIUP Diisoundecyl phthalate
475.3782 C6H4(COO(CH2)10CH3)2 DUP Diundecyl phthalate
481.261935 [C2H4O]nH2O PEG Polyethylene glycol, ubiquitous polyether
483.352761 [C3H6O]nH2O PPG Polypropylene glycol, ubiquitous polyether
485.347281 [C15H24O][C2H4O]n Triton 101 Detergents
493.313575 [C14H22O][C2H4O]n Triton X-100, X-114, X-405, or X-45 Detergents
494.565925 C34H72NCl DPDMA Dipalmityldimethylammonium chloride, personal care products additive
497.235872 [C2H4O]nH2O PEG Polyethylene glycol, ubiquitous polyether
499.360525 [C14H28O][C2H4O]n Triton, reduced X-100R, X-114R, X-405R, or X-45R Detergents
503.107520 [C2H6SiO]7 Polysiloxane Polysiloxane, (neutral methane loss from m/z 519)
503.306206 [C2H4O]nH2O PEG Polyethylene glycol, ubiquitous polyether
505.334705 [C3H6O]nH2O PPG Polypropylene glycol, ubiquitous polyether
507.329225 [C15H24O][C2H4O]n Triton 101 Detergents
513.376175 [C15H30O][C2H4O]n Triton, reduced 101R Detergents
515.357846 [C14H22O][C2H4O]n Triton X-100, X-114, X-405, or X-45 Detergents
515.412857 C30H58O4S DDTDP Didodecyl 3,3’-thiodipropionate, antioxidant
519.138820 [C2H6SiO]7 Polysiloxane Polysiloxane, followed by m/z 536
521.308642 [C3H6O]nH2O PPG Polypropylene glycol, ubiquitous polyether
522.597225 C36H76NCl SPDMA Stearyl-palmityldimethylammonium chloride, personal care product additive
525.288150 [C2H4O]nH2O PEG Polyethylene glycol, ubiquitous polyether
529.373496 [C15H24O][C2H4O]n Triton 101 Detergents
531.407772 C30H58O5S DDTDP Didodecyl 3,3’-thiodipropionate oxidized to sulfoxide, antioxidant
531.4408 C6H4(COO(CH2)10CH(CH3)2)2 DIUP Diisotridecyl phthalate
531.4408 C6H4(COO(CH2)12CH3)2 DTDP Ditridecyl phthalate
531.477171 C35H62O3 Irganox Irganox 1076, antioxidant in synthetic polymers, antioxidant
536.165369 [C2H6SiO]7 Polysiloxane Polysiloxane (see m/z 519)
537.339790 [C14H22O][C2H4O]n Triton X-100, X-114, X-405, or X-45 Detergents
537.879009 C2H4O2 AA-Fe-O- complex during ESI with metal tips and AA
541.262087 [C2H4O]nH2O PEG Polyethylene glycol, ubiquitous polyether
541.394626 [C3H6O]nH2O PPG Polypropylene glycol, ubiquitous polyether
543.386740 [C14H28O][C2H4O]n Triton, reduced X-100R, X-114R, X-405R, or X-45R Detergents
547.332421 [C2H4O]nH2O PEG Polyethylene glycol, ubiquitous polyether
547.402687 C30H58O6S DDTDP Didodecyl 3,3’-thiodipropionate oxidized to sulfone, antioxidant
550.628525 C38H80NCl DSDMA Distearyldimethylammonium chloride, personal care products additive
551.355440 [C15H24O][C2H4O]n Triton 101 Detergents
553.389716 C30H58O5S DDTDP Didodecyl 3,3’-thiodipropionate oxidized to sulfoxide, antioxidant
553.459115 C35H62O3 Irganox Irganox 1076, antioxidant in synthetic polymers, antioxidant
555.889574 C2H4O2 AA-Fe-O- complex during ESI with metal tips and AA
557.402390 [C15H30O][C2H4O]n Triton, reduced 101R Detergents
559.384061 [C14H22O][C2H4O]n Triton X-100, X-114, X-405, or X-45 Detergents
563.376570 [C3H6O]nH2O PPG Polypropylene glycol, ubiquitous polyether
568.135058 C10H7NO3 4-HCCA matrix cluster, trimer
569.314365 [C2H4O]nH2O PEG Polyethylene glycol, ubiquitous polyether
573.399711 [C15H24O][C2H4O]n Triton 101 Detergents
577.126312 [C2H6SiO]8 Polysiloxane Polysiloxane, (neutral methane loss from m/z 593)
579.350507 [C3H6O]nH2O PPG Polypropylene glycol, ubiquitous polyether
581.366005 [C14H22O][C2H4O]n Triton X-100, X-114, X-405, or X-45 Detergents
585.288302 [C2H4O]nH2O PEG Polyethylene glycol, ubiquitous polyether
585.358571 C30H58O6S Didodecyl 3,3’-thiodipropionate sulfone product Antioxidant
587.412955 [C14H28O][C2H4O]n Triton, reduced X-100R, X-114R, X-405R, or X-45R Detergents
591.358636 [C2H4O]nH2O PEG Polyethylene glycol, ubiquitous polyether
593.157612 [C2H6SiO]8 Polysiloxane Polysiloxane, followed by m/z 610
595.381655 [C15H24O][C2H4O]n Triton 101 Detergents
597.900139 C2H4O2 AA-Fe-O- complex during ESI with metal tips and AA
599.436491 [C3H6O]nH2O PPG Polypropylene glycol, ubiquitous polyether
601.428605 [C15H30O][C2H4O]n Triton, reduced 101R Detergents
603.410276 [C14H22O][C2H4O]n Triton X-100, X-114, X-405, or X-45 Detergents
605.292279 C24H44N4O4 Nylon 66 polymer Filter
606.091488 C10H7NO3 4-HCCA matrix cluster, trimer, potassiated
610.184161 [C2H6SiO]8 Polysiloxane Polysiloxane (see m/z 593)
613.340580 [C2H4O]nH2O PEG Polyethylene glycol, ubiquitous polyether
615.403750 C32H58N2O7S CHAPS 3-[(3-Cholamidopropyl)dimethylammonio]-1-propanesulfonate
617.425926 [C15H24O][C2H4O]n Triton 101 Detergents
621.418435 [C3H6O]nH2O PPG Polypropylene glycol, ubiquitous polyether
621.972909 C3H6O2 Propionic acid Fe-O complex during ESI with metal tips and AA
625.392220 [C14H22O][C2H4O]n Triton X-100, X-114, X-405, or X-45 Detergents
629.314517 [C2H4O]nH2O PEG Polyethylene glycol, ubiquitous polyether
631.439170 [C14H28O][C2H4O]n Triton, reduced X-100R, X-114R, X-405R, or X-45R Detergents
635.384851 [C2H4O]nH2O PEG Polyethylene glycol, ubiquitous polyether
637.392372 [C3H6O]nH2O PPG Polypropylene glycol, ubiquitous polyether
639.407870 [C15H24O][C2H4O]n Triton 101 Detergents
644.046824 C10H7NO3 4-HCCA Matrix compound
645.454820 [C15H30O][C2H4O]n Triton, reduced 101R Detergents
647.436491 [C14H22O][C2H4O]n Triton X-100, X-114, X-405, or X-45 Detergents
651.145104 [C2H6SiO]9 Polysiloxane Polysiloxane, (neutral methane loss from m/z 667)
657.366795 [C2H4O]nH2O PEG Polyethylene glycol, ubiquitous polyether
657.478356 [C3H6O]nH2O PPG Polypropylene glycol, ubiquitous polyether
657.921273 C2H4O2 AA Solvent
661.452141 [C15H24O][C2H4O]n Triton 101 Detergents
666.028769 C10H7NO3 4-HCCA Matrix compound
667.176404 [C2H6SiO]9 Polysiloxane Polysiloxane, followed by m/z 684
669.418435 [C14H22O][C2H4O]n Triton X-100, X-114, X-405, or X-45 Detergents
673.340732 [C2H4O]nH2O PEG Polyethylene glycol, ubiquitous polyether
675.465385 [C14H28O][C2H4O]n Triton, reduced X-100R, X-114R, X-405R, or X-45R Detergents
679.411066 [C2H4O]nH2O PEG Polyethylene glycol, ubiquitous polyether
679.460300 [C3H6O]nH2O PPG Polypropylene glycol, ubiquitous polyether
679.511660 C36H66N6O6 nylon Cyclic oligomer of polyamide 66
680.994882 C10H7NO3 4-HCCA Matrix compound
683.434085 [C15H24O][C2H4O]n Triton 101 Detergents
684.202953 [C2H6SiO]9 Polysiloxane Polysiloxane (see m/z 667)
689.481035 [C15H30O][C2H4O]n Triton, reduced 101R Detergents
691.462706 [C14H22O][C2H4O]n Triton X-100, X-114, X-405, or X-45 Detergents
695.434237 [C3H6O]nH2O PPG Polypropylene glycol, ubiquitous polyether
701.393010 [C2H4O]nH2O PEG Polyethylene glycol, ubiquitous polyether
701.493605 C36H66N6O6 Nylon 66 polymer Filter
705.478356 [C15H24O][C2H4O]n Triton 101 Detergents
713.444650 [C14H22O][C2H4O]n Triton X-100, X-114, X-405, or X-45 Detergents
715.520221 [C3H6O]nH2O PPG Polypropylene glycol, ubiquitous polyether
717.366947 [C2H4O]nH2O PEG Polyethylene glycol, ubiquitous polyether
717.467543 C36H66N6O6 Nylon 66 polymer Filter
719.491600 [C14H28O][C2H4O]n Triton, reduced X-100R, X-114R, X-405R, or X-45R Detergents
723.437281 [C2H4O]nH2O PEG Polyethylene glycol, ubiquitous polyether
725.163896 [C2H6SiO]10 Polysiloxane Polysiloxane, (neutral methane loss from m/z 741)
727.460300 [C15H24O][C2H4O]n Triton 101 Detergents
733.507250 [C15H30O][C2H4O]n Triton, reduced 101R Detergents
735.488921 [C14H22O][C2H4O]n Triton X-100, X-114, X-405, or X-45 Detergents
737.502165 [C3H6O]nH2O PPG Polypropylene glycol, ubiquitous polyether
741.195196 [C2H6SiO]10 Polysiloxane Polysiloxane, followed by m/z 758
745.419225 [C2H4O]nH2O PEG Polyethylene glycol, ubiquitous polyether
749.504571 [C15H24O][C2H4O]n Triton 101 Detergents
753.476102 [C3H6O]nH2O PPG Polypropylene glycol, ubiquitous polyether
757.470865 [C14H22O][C2H4O]n Triton X-100, X-114, X-405, or X-45 Detergents
758.221745 [C2H6SiO]10 Polysiloxane Polysiloxane (see m/z 741)
761.393162 [C2H4O]nH2O PEG Polyethylene glycol, ubiquitous polyether
763.517815 [C14H28O][C2H4O]n Triton, reduced X-100R, X-114R, X-405R, or X-45R Detergents
767.463496 [C2H4O]nH2O PEG Polyethylene glycol, ubiquitous polyether
770.046473 C3H6O2 Propionic acid na
771.486515 [C15H24O][C2H4O]n Triton 101 Detergents
773.562086 [C3H6O]nH2O PPG Polypropylene glycol, ubiquitous polyether
777.533465 [C15H30O][C2H4O]n Triton, reduced 101R Detergents
779.515136 [C14H22O][C2H4O]n Triton X-100, X-114, X-405, or X-45 Detergents
789.445440 [C2H4O]nH2O PEG Polyethylene glycol, ubiquitous polyether
793.530786 [C15H24O][C2H4O]n Triton 101 Detergents
795.544030 [C3H6O]nH2O PPG Polypropylene glycol, ubiquitous polyether
798.587845 C24H38O4 Diisooctyl phthalate Diisooctyl phthalate, plasticiser
801.497080 [C14H22O][C2H4O]n Triton X-100, X-114, X-405, or X-45 Detergents
803.543240 C24H38O4 Diisooctyl phthalate Diisooctyl phthalate, plasticiser
805.419377 [C2H4O]nH2O PEG Polyethylene glycol, ubiquitous polyether
807.544030 [C14H28O][C2H4O]n Triton, reduced X-100R, X-114R, X-405R, or X-45R Detergents
809.486910 [C18H34O6][C2H4O]n Tween Tween 20
811.489711 [C2H4O]nH2O PEG Polyethylene glycol, ubiquitous polyether
811.517967 [C3H6O]nH2O PPG Polypropylene glycol, ubiquitous polyether
815.512730 [C15H24O][C2H4O]n Triton 101 Detergents
819.517177 C24H38O4 Diisooctyl phthalate Diisooctyl phthalate, plasticiser
821.559680 [C15H30O][C2H4O]n Triton, reduced 101R Detergents
823.541351 [C14H22O][C2H4O]n Triton X-100, X-114, X-405, or X-45 Detergents
831.460407 C36H66N6O6 Nylon 66 polymer Filter
831.603951 [C3H6O]nH2O PPG Polypropylene glycol, ubiquitous polyether
833.089418 C10H7NO3 4-HCCA Matrix compound
833.471655 [C2H4O]nH2O PEG Polyethylene glycol, ubiquitous polyether
837.557001 [C15H24O][C2H4O]n Triton 101 Detergents
839.097421 C10H7NO3 4-HCCA matrix cluster
845.105428 C10H7NO3 4-HCCA matrix cluster
845.523295 [C14H22O][C2H4O]n Triton X-100, X-114, X-405, or X-45 Detergents
849.445592 [C2H4O]nH2O PEG Polyethylene glycol, ubiquitous polyether
851.570245 [C14H28O][C2H4O]n Triton, reduced X-100R, X-114R, X-405R, or X-45R Detergents
853.513125 [C18H34O6][C2H4O]n Tween Tween 20
853.585895 [C3H6O]nH2O PPG Polypropylene glycol, ubiquitous polyether
855.071358 C10H7NO3 4-HCCA matrix cluster
855.515926 [C2H4O]nH2O PEG Polyethylene glycol, ubiquitous polyether
859.538945 [C15H24O][C2H4O]n Triton 101 Detergents
861.079365 C10H7NO3 4-HCCA matrix cluster
865.549510 [C22H42O6][C2H4O]n Tween Tween 40
865.585895 [C15H30O][C2H4O]n Triton, reduced 101R Detergents
867.087372 C10H7NO3 4-HCCA matrix cluster
867.567566 [C14H22O][C2H4O]n Triton X-100, X-114, X-405, or X-45 Detergents
869.559832 [C3H6O]nH2O PPG Polypropylene glycol, ubiquitous polyether
871.045295 C10H7NO3 4-HCCA matrix cluster
877.497870 [C2H4O]nH2O PEG Polyethylene glycol, ubiquitous polyether
881.583216 [C15H24O][C2H4O]n Triton 101 Detergents
889.549510 [C14H22O][C2H4O]n Triton X-100, X-114, X-405, or X-45 Detergents
889.645816 [C3H6O]nH2O PPG Polypropylene glycol, ubiquitous polyether
891.565160 [C24H44O6][C2H4O]n Tween Tween 80
893.471807 [C2H4O]nH2O PEG Polyethylene glycol, ubiquitous polyether
893.580810 [C24H46O6][C2H4O]n Tween Tween 60
895.596460 [C14H28O][C2H4O]n Triton, reduced X-100R, X-114R, X-405R, or X-45R Detergents
897.539340 [C18H34O6][C2H4O]n Tween Tween 20
899.542141 [C2H4O]nH2O PEG Polyethylene glycol, ubiquitous polyether
903.565160 [C15H24O][C2H4O]n Triton 101 Detergents
905.679788 C48H88N8O8 nylon Cyclic oligomer of polyamide 66
907.993359 C10H7NO3 4-HCCA Matrix compound
909.575725 [C22H42O6][C2H4O]n Tween Tween 40
909.612110 [C15H30O][C2H4O]n Triton, reduced 101R Detergents
911.593781 [C14H22O][C2H4O]n Triton X-100, X-114, X-405, or X-45 Detergents
911.627760 [C3H6O]nH2O PPG Polypropylene glycol, ubiquitous polyether
921.524085 [C2H4O]nH2O PEG Polyethylene glycol, ubiquitous polyether
925.609431 [C15H24O][C2H4O]n Triton 101 Detergents
927.601697 [C3H6O]nH2O PPG Polypropylene glycol, ubiquitous polyether
933.575725 [C14H22O][C2H4O]n Triton X-100, X-114, X-405, or X-45 Detergents
935.591375 [C24H44O6][C2H4O]n Tween Tween 80
937.498022 [C2H4O]nH2O PEG Polyethylene glycol, ubiquitous polyether
937.607025 [C24H46O6][C2H4O]n Tween Tween 60
939.622675 [C14H28O][C2H4O]n Triton, reduced X-100R, X-114R, X-405R, or X-45R Detergents
941.565555 [C18H34O6][C2H4O]n Tween Tween 20
947.591375 [C15H24O][C2H4O]n Triton 101 Detergents
947.687681 [C3H6O]nH2O PPG Polypropylene glycol, ubiquitous polyether
953.601940 [C22H42O6][C2H4O]n Tween Tween 40
953.638325 [C15H30O][C2H4O]n Triton, reduced 101R Detergents
955.619996 [C14H22O][C2H4O]n Triton X-100, X-114, X-405, or X-45 Detergents
969.635646 [C15H24O][C2H4O]n Triton 101 Detergents
969.669625 [C3H6O]nH2O PPG Polypropylene glycol, ubiquitous polyether
977.601940 [C14H22O][C2H4O]n Triton X-100, X-114, X-405, or X-45 Detergents
979.617590 [C24H44O6][C2H4O]n Tween Tween 80
981.633240 [C24H46O6][C2H4O]n Tween Tween 60
983.648890 [C14H28O][C2H4O]n Triton, reduced X-100R, X-114R, X-405R, or X-45R Detergents
985.591770 [C18H34O6][C2H4O]n Tween Tween 20
985.643562 [C3H6O]nH2O PPG Polypropylene glycol, ubiquitous polyether
991.617590 [C15H24O][C2H4O]n Triton 101 Detergents
994.155513 C10H7NO3 4-HCCA matrix cluster
997.628155 [C22H42O6][C2H4O]n Tween Tween 40
997.664540 [C15H30O][C2H4O]n Triton, reduced 101R Detergents
999.646211 [C14H22O][C2H4O]n Triton X-100, X-114, X-405, or X-45 Detergents
1005.729546 [C3H6O]nH2O PPG Polypropylene glycol, ubiquitous polyether
1013.661861 [C15H24O][C2H4O]n Triton 101 Detergents
1021.628155 [C14H22O][C2H4O]n Triton X-100, X-114, X-405, or X-45 Detergents
1023.643805 [C24H44O6][C2H4O]n Tween Tween 80
1025.659455 [C24H46O6][C2H4O]n Tween Tween 60
1027.675105 [C14H28O][C2H4O]n Triton, reduced X-100R, X-114R, X-405R, or X-45R Detergents
1027.711490 [C3H6O]nH2O PPG Polypropylene glycol, ubiquitous polyether
1029.617985 [C18H34O6][C2H4O]n Tween Tween 20
1035.643805 [C15H24O][C2H4O]n Triton 101 Detergents
1036.082773 C10H7NO3 4-HCCA matrix cluster
1041.654370 [C22H42O6][C2H4O]n Tween Tween 40
1041.690755 [C15H30O][C2H4O]n Triton, reduced 101R Detergents
1043.672426 [C14H22O][C2H4O]n Triton X-100, X-114, X-405, or X-45 Detergents
1043.685427 [C3H6O]nH2O PPG Polypropylene glycol, ubiquitous polyether
1044.113952 C10H7NO3 4-HCCA matrix cluster
1054.093338 C10H7NO3 4-HCCA matrix cluster
1057.688076 [C15H24O][C2H4O]n Triton 101 Detergents
1060.087889 C10H7NO3 4-HCCA matrix cluster, pentamer, triply potassiated
1063.771411 [C3H6O]nH2O PPG Polypropylene glycol, ubiquitous polyether
1065.654370 [C14H22O][C2H4O]n Triton X-100, X-114, X-405, or X-45 Detergents
1066.095896 C10H7NO3 4-HCCA matrix cluster, pentamer, potassiated, sodiated
1067.670020 [C24H44O6][C2H4O]n Tween Tween 80
1069.685670 [C24H46O6][C2H4O]n Tween Tween 60
1071.701320 [C14H28O][C2H4O]n Triton, reduced X-100R, X-114R, X-405R, or X-45R Detergents
1073.644200 [C18H34O6][C2H4O]n Tween Tween 20
1079.670020 [C15H24O][C2H4O]n Triton 101 Detergents
1085.680585 [C22H42O6][C2H4O]n Tween Tween 40
1085.716970 [C15H30O][C2H4O]n Triton, reduced 101R Detergents
1085.753355 [C3H6O]nH2O PPG Polypropylene glycol, ubiquitous polyether
1087.698641 [C14H22O][C2H4O]n Triton X-100, X-114, X-405, or X-45 Detergents
1101.714291 [C15H24O][C2H4O]n Triton 101 Detergents
1101.727292 [C3H6O]nH2O PPG Polypropylene glycol, ubiquitous polyether
1109.680585 [C14H22O][C2H4O]n Triton X-100, X-114, X-405, or X-45 Detergents
1111.696235 [C24H44O6][C2H4O]n Tween Tween 80
1113.711885 [C24H46O6][C2H4O]n Tween Tween 60
1115.727535 [C14H28O][C2H4O]n Triton, reduced X-100R, X-114R, X-405R, or X-45R Detergents
1117.670415 [C18H34O6][C2H4O]n Tween Tween 20
1121.813276 [C3H6O]nH2O PPG Polypropylene glycol, ubiquitous polyether
1123.696235 [C15H24O][C2H4O]n Triton 101 Detergents
1129.706800 [C22H42O6][C2H4O]n Tween Tween 40
1129.743185 [C15H30O][C2H4O]n Triton, reduced 101R Detergents
1143.795220 [C3H6O]nH2O PPG Polypropylene glycol, ubiquitous polyether
1155.722450 [C24H44O6][C2H4O]n Tween Tween 80
1157.738100 [C24H46O6][C2H4O]n Tween Tween 60
1159.769157 [C3H6O]nH2O PPG Polypropylene glycol, ubiquitous polyether
1161.696630 [C18H34O6][C2H4O]n Tween Tween 20
1173.733015 [C22H42O6][C2H4O]n Tween Tween 40
1179.855141 [C3H6O]nH2O PPG Polypropylene glycol, ubiquitous polyether
1199.748665 [C24H44O6][C2H4O]n Tween Tween 80
1201.764315 [C24H46O6][C2H4O]n Tween Tween 60
1201.837085 [C3H6O]nH2O PPG Polypropylene glycol, ubiquitous polyether
1205.722845 [C18H34O6][C2H4O]n Tween Tween 20
1217.759230 [C22H42O6][C2H4O]n Tween Tween 40
1217.811022 [C3H6O]nH2O PPG Polypropylene glycol, ubiquitous polyether
1225.125367 C10H7NO3 4-HCCA matrix cluster, hexamer, potassiated, sodiated
1229.800224 C32H58N2O7S CHAPS 3-[(3-Cholamidopropyl)dimethylammonio]-1-propanesulfonate
1243.774880 [C24H44O6][C2H4O]n Tween Tween 80
1245.790530 [C24H46O6][C2H4O]n Tween Tween 60
1249.749060 [C18H34O6][C2H4O]n Tween Tween 20
1261.785445 [C22H42O6][C2H4O]n Tween Tween 40
1287.801095 [C24H44O6][C2H4O]n Tween Tween 80
1289.816745 [C24H46O6][C2H4O]n Tween Tween 60
1293.775275 [C18H34O6][C2H4O]n Tween Tween 20
1305.811660 [C22H42O6][C2H4O]n Tween Tween 40
1331.827310 [C24H44O6][C2H4O]n Tween Tween 80
1333.842960 [C24H46O6][C2H4O]n Tween Tween 60
1337.801490 [C18H34O6][C2H4O]n Tween Tween 20
1349.837875 [C22H42O6][C2H4O]n Tween Tween 40
1375.853525 [C24H44O6][C2H4O]n Tween Tween 80
1377.869175 [C24H46O6][C2H4O]n Tween Tween 60
1381.827705 [C18H34O6][C2H4O]n Tween Tween 20
1393.864090 [C22H42O6][C2H4O]n Tween Tween 40
1419.879740 [C24H44O6][C2H4O]n Tween Tween 80
1421.895390 [C24H46O6][C2H4O]n Tween Tween 60
1425.853920 [C18H34O6][C2H4O]n Tween Tween 20
1437.890305 [C22H42O6][C2H4O]n Tween Tween 40
1463.905955 [C24H44O6][C2H4O]n Tween Tween 80
1465.921605 [C24H46O6][C2H4O]n Tween Tween 60
1469.880135 [C18H34O6][C2H4O]n Tween Tween 20
1481.916520 [C22H42O6][C2H4O]n Tween Tween 40
1507.932170 [C24H44O6][C2H4O]n Tween Tween 80
1509.947820 [C24H46O6][C2H4O]n Tween Tween 60
1513.906350 [C18H34O6][C2H4O]n Tween Tween 20
1525.942735 [C22H42O6][C2H4O]n Tween Tween 40
1551.958385 [C24H44O6][C2H4O]n Tween Tween 80
1553.974035 [C24H46O6][C2H4O]n Tween Tween 60
1557.932565 [C18H34O6][C2H4O]n Tween Tween 20
1569.968950 [C22H42O6][C2H4O]n Tween Tween 40
1595.984600 [C24H44O6][C2H4O]n Tween Tween 80
1598.000250 [C24H46O6][C2H4O]n Tween Tween 60
1601.958780 [C18H34O6][C2H4O]n Tween Tween 20
1613.995165 [C22H42O6][C2H4O]n Tween Tween 40
1640.010815 [C24H44O6][C2H4O]n Tween Tween 80
1642.026465 [C24H46O6][C2H4O]n Tween Tween 60
1645.984995 [C18H34O6][C2H4O]n Tween Tween 20
1658.021380 [C22H42O6][C2H4O]n Tween Tween 40
1684.037030 [C24H44O6][C2H4O]n Tween Tween 80
1686.052680 [C24H46O6][C2H4O]n Tween Tween 60
1690.011210 [C18H34O6][C2H4O]n Tween Tween 20
1702.047595 [C22H42O6][C2H4O]n Tween Tween 40
1728.063245 [C24H44O6][C2H4O]n Tween Tween 80
1730.078895 [C24H46O6][C2H4O]n Tween Tween 60
1734.037425 [C18H34O6][C2H4O]n Tween Tween 20
1746.073810 [C22H42O6][C2H4O]n Tween Tween 40
1772.089460 [C24H44O6][C2H4O]n Tween Tween 80
1774.105110 [C24H46O6][C2H4O]n Tween Tween 60
1778.063640 [C18H34O6][C2H4O]n Tween Tween 20
1790.100025 [C22H42O6][C2H4O]n Tween Tween 40
1816.115675 [C24H44O6][C2H4O]n Tween Tween 80
1818.131325 [C24H46O6][C2H4O]n Tween Tween 60
1834.126240 [C22H42O6][C2H4O]n Tween Tween 40
1860.141890 [C24H44O6][C2H4O]n Tween Tween 80
1862.157540 [C24H46O6][C2H4O]n Tween Tween 60