MALDI TIME-OF-FLIGHT MASS SPECTROMETRY OF SYNTHETIC POLYMERS
Michel W.F. Nielen Akzo Nobel Chemicals Research, P.O. Box 9300, 6800 SB Arnhem, The Netherlands Received 26 April 1999; accepted 12 August 1999
I. Introduction ...... 309 II. Matrix Selection for Polymer Analysis ...... 310 A. Matrices for UV±MALDI ...... 310 B. Matrices for IR±MALDI ...... 317 III. Cationization in Polymer Analysis ...... 319 IV. Sample Preparation Techniques ...... 320 V. Discrimination Issues ...... 321 A. High and Low Mass Discrimination ...... 321 B. Oligomer Speci®c Discrimination ...... 324 VI. MS/MS in MALDI TOF MS of Synthetic Polymers ...... 325 VII. Chromatography/MALDI Coupling ...... 327 A. Thin Layer Chromatography/MALDI TOF MS ...... 327 B. Off-line Size-Exclusion Chromatography/MALDI TOF MS ...... 328 C. On-line and Direct Deposition Size-Exclusion Chromatography/MALDI TOF MS ...... 329 D. Other Liquid Chromatography Modes Coupled with MALDI TOF MS ...... 330 VIII. Polymer Applications ...... 331 A. Homopolymers ...... 331 B. Blends ...... 333 C. Copolymers and Resins ...... 334 D. Miscellaneous ...... 334 IX. Conclusion and Outlook ...... 334 References ...... 336
Mass spectrometry of intact synthetic polymers has been limited as size exclusion chromatography (SEC)/MALDI have been to ®eld desorption (FD) MS for many years. More recently, soft developed. Many different polymer applications appeared in ionization techniques such as electrospray (ESI) and matrix- recent literature, but most studies deal with homopolymers. assisted laser desorption/ionization (MALDI) and the revival of Many challenges remain, particularly in the ®elds of haloge- time-of-¯ight analyzers created new opportunities for the nated polymers, polyole®nes, copolymers, blends, and in the characterization of polymers. In this review emphasis is put sequencing of block-copolymers. # 1999 John Wiley & Sons, on MALDI time-of-¯ight mass spectrometry of polymers. The Inc., Mass Spec Rev 18: 309±344, 1999 selection of an appropriate MALDI matrix, cationization salt and sample preparation techniques are critical success factors for obtaining a reliable mass spectrum and to infer structural I. INTRODUCTION information such as monomer mass(es) and end-groups. However even under optimized conditions mass discrimination Among the analytical techniques currently used in the in the analysis of polydisperse polymers and speci®c oligomer characterization of synthetic polymers, mass spectro- discrimination might occur. Hence hyphenated techniques such metry is of increasing importance (Smith et al., 1997). In ÐÐÐÐ the past, mass spectrometry of synthetic polymers was hardly possible: as a rule, polymers had to be degraded Correspondence to: Michel W.F. Nielen; e-mail: michel.nielen@ akzonobel.com thermally or chemically prior to mass spectrometric
Mass Spectrometry Reviews, 1999, 18, 309± 344 # 1999 by John Wiley & Sons, Inc. CCC 0277-7037/99/050309-36 97 u&Oo,19;Ree crp,1998). Schrepp, & Raeder 1998; Odom, & the Wu Simonsick, & 1997; be until Jackson can 1996; topic (Montaudo, same literature elsewhere the found on the reviews short covers 1999; of beginning and polymers synthetic kDa. 35 to up mass) end-groups cation the the known (i.e., (i.e., residue plus mass increment the and mass mass) complexityÐthe repeating monomer polymer the of the of and range determination mass & the monomer allowingÐdepending Brown the in thereby on 1955; resolution (FWHM) McLaren, offer 10,000±20,000 & which (Wiley 1995) Lennon, source extrac- delayed ion with tion equipped molecular instruments re¯ectron state-of-the high the art and 1996); very been Li, has & MDa (Schriemer which 1 demonstrated beyond time-of- analyzed, in be the can polymers analyzer fragmentation; weight any (TOF) mole- hardly ¯ight quasi mass with single-charged the ions of mainly cular simplicity show the which of spectra because analysis polymer analyses. FTD limited and are all studies MWD and most of to far ESI characterization so the although samples, distributions, to ®ve contribute polymer can of MS MALDI complexity the Despite hntepoenstaindet h oxsec fseveral of coexistence the to distributions: due well, situation complex as protein more the is analysis than situation polymer polymer synthetic to the amenable although and are ESI that an MS recognized as have been MALDI such has still biopolymers It peptides. and of and analysis had proteins the 1988) Hillen- on al., as impact & enormous et Tanaka such (Karas 1988; MALDI kamp, techniques matrix-assisted and desorption/ionization, 1990), ionization al., laser et (Prokai, (Fenn soft spectro- kDa ESI 10 electrospray, mass to Modern up the polymers for 1990). intact option of analysis only sector metric the on (FD) was desorption ®eld instruments years, many For analysis. & 310 NIELEN * * * * * hsrve srsrce oMLITFM of MS TOF MALDI to restricted is review This for suited ideally is MS time-of-¯ight MALDI c)oyesso nacietr distribution dendritic). branched, architecture cyclic, an (linear, show (co)polymers present, are sequence distribution additional block-length copolymers, and block dis- of composition case in chemical a (CCD), tribution addition in chains polymer the show copolymers, random of case func- in (FTD), a distribution creating type and end- tionality thereby initiation different processes, different to have termination due might chemistries chains group polymer synthesis, the polymer of result (MWD) to a distribution have as weight we molecular weight, a with molecular deal single a of instead eeto a eetatdfo oye n matrix and polymer 1998): from Owens, & extracted (Hanton matrix data for be solubility guidelines can general some selection applied. polymers, be could other peptides of same For the analysis because the simply in MS, used MALDI matrices of days early studied the in already polymer were polypropyleneglycol any and giving leneglycol spots those the for for even only signal. cases intensity not signal in search and polymers, resolution to but good has showing synthetic spots one sweet often of are and preparations MALDI sample obtained are inhomogeneous samples In rather homogeneous typically obtained. routines rule, a peptide being acquisition in as well quite wherein, data perform analysis which 1997) within manu- al., automated et Instrument (Suckau distributions offer above. not outlined the is facturers as this of samples situation In polymer protein sample because molecules. and and peptide matrix straightforward the salt and to sample homogeneous solvent, contrast is of matrix, experiment MALDI cocrystallization of any in goal preparation ®nal The ANALYSIS POLYMER FOR SELECTION MATRIX II. fet,eg,dtrnli ucsflyue ihsle salts silver with used background successfully and is dithranol incompatibilities e.g., the effects, of aware are mass be should solvents MALDI matrix the and in polymer molecular included. addition, high observed molecular In the actually The spectra. to 1. end refer Table weight therein documented in indicated with given weights is polymers matrices synthetic MALDI of overview An UV±MALDI for Matrices A. literature. in found some be point, and can starting UV±MALDI IR±MALDI a for for as hints process; matrix error on and analysis suggestions Nevertheless, trial many polymer a investigation. for often Polystyrene still optimization is under and Polydimethylsiloxane selection polymer matrix the polarity matrix glycol the with match Polytetramethylene to recommended is it Polymethylmethacrylate Generally, Polymers Diphenylbutadiene trans all Dithranol glycol acid Polypropylene Indoleacrylic acid Ferulic acid 2,5-Dihydroxybenzoic Matrices Caohdoyinmcai oyiy acetate Polyvinyl acid -Cyano-hydroxycinnamic ae-oul ytei oyessc spolyethy- as such polymers synthetic Water-soluble biul aymti pin r vial u one but available are options matrix many Obviously Rtni cdPolybutadiene acid -Retinoic Hydrophobic $ Hydrophilic MALDI TOF MS OF SYNTHETIC POLYMERS &
TABLE 1. Matrices for UV±MALDI mass spectrometry of speci®c synthetic polymers Polymer Matrix Matrix solvent Polymer solvent MW Reference
PEG SA 1500 Zenobi, 1994 PEG HABA THF 24,000 Montaudo et al., 1995a PEG DHB water acetonitrile±water 2400 Pasch & Rode, 1995 PEG DHB ethanol 24,000 Montaudo et al., 1995c PEG HABA dioxane methanol 4500 Whittal & Li, 1995 PEG ACA/MSA ethanol methanol 8000 Tang et al., 1995b PEG DHB dichloromethane 5000 Weidner et al., 1996b PEG glycerol/graphite methanol 8000 Dale et al., 1996 PEG NBA/graphite methanol 8000 Dale et al., 1996 PEG hydroxymethoxycinnamic methanol methanol 1000 Fei & Murray, 1996 acid PEG MBT 14,000 Xu et al., 1997 PEG AMBT EtOH/THF/water EtOH/THF/water 14,000 Xu et al., 1997
PEG K4[Fe(CN)6]/glycerol methanol/glycerol chloroform 8000 Zollner et al. 1997 PEG glassy azodyes 1500 Blair et al., 1998 PEG, pyrene- HABA dioxane methanol Whittal et al., 1996 PEG, derivatized- DHB ethanol/water DMSO 5000 Weidner & Kuhn, 1996 PEG, dimethyl- salicylamide ethanol/water water 1600 Krause et al., 1996 PEG, dimethyl- salicylanilide ethanol water 5200 Krause et al., 1996 PEG, carbonate- CHCA acetone water/acetone 7000 Hagelin et al., 1998 PTMEG DHB 1000 King et al., 1995 PTMEG DHB THF THF 9000 Jackson C et al., 1996 PPG ACA/MSA 6500 Tang et al., 1995a PPG DHB methanol±water (1:1) 2400 Barton et al., 1995 Polyether, CHCA acetonitrile/water methylene chloride 5000 Peiris et al., 1998 -azoxyaromatic Coal SA chloroform/methanol 70,000 Herod et al., 1994a Coal SA 270,000 Herod et al., 1994b Coal trihydroxyanthracene 200,000 Herod et al., 1995 Coal, -tar pitch SA, DHB 260,000 John et al., 1994 Coal, -tar various NMP NMP 100,000 Domin et al., 1997 Coal, -tar pitch none 10,000 Johnson et al., 1998 PMMA IAA acetone acetone 260,000 Danis & Karr, 1993 PMMA DHB acetone acetone 260,000 Danis & Karr, 1993 PMMA DHB water/acetonitrile acetone 9000 Danis et al., 1993 PMMA DHB water/ethanol THF 3000 Lehrle & Sarson, 1995 PMMA HABA THF 90,000 Montaudo et al., 1995a PMMA DHB THF 9500 Lloyd et al., 1995 PMMA ACA/MSA ethanol toluene 8000 Tang et al., 1995b PMMA DHB 50,000 Cottrell et al., 1995 PMMA IAA acetone acetone 50,000 Belu et al., 1996 PMMA IAA acetone acetone 7000 Larsen et al., 1996 PMMA DHB ethanol±water THF 4000 Lehrle & Sarson, 1996 PMMA DHB THF THF 15,000 Jackson C et al., 1996 PMMA DHB THF 3000 Weidner et al., 1996b PMMA DHB methanol methanol 6000 Dogruel et al., 1996 PMMA DHB CsI methanol methanol 6000 Dogruel et al., 1996 (Continued)
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TABLE 1. (Continued) Polymer Matrix Matrix solvent Polymer solvent MW Reference
PMMA IAA THF THF 110,000 Schweer et al., 1996 PMMA DHB KtFAc THF THF 10,000 Spickermann et al., 1996 PMMA MBT Xu et al., 1997 PMMA dithranol surfactants 6500 Kassis et al., 1996 PMMA dithranol THF THF 20,000 Jackson AT et al., 1997a PMMA HABA THF acetone or THF 50,000 Rashidzadeh et al. 1998a PMMA, end-groups DHB acetone 4000 Maloney et al., 1995 PMMA, end-groups DHB THF 3500 Pasch and Gores, 1995 PMMA, end-groups IAA acetone 9200 Scrivens et al., 1995 PMMA, end-groups DHB acetone acetone 6000 Hunt et al., 1995 PMMA, end groups dithranol HFIP HFIP 13,000 Jackson, AT et al., 1997b PBA DHB acetone acetone Easterling et al., 1998 PBA IAA THF THF 200,000 Nielen & Malucha, 1997 PBMA IAA acetone acetone 100,000 Danis et al., 1995 Polyacrylate, ¯uorinated DHB THF trichlorotri¯uoroethane 25,000 Latourte et al., 1997b PS IAA THF Danis & Karr, 1993 PS HABA THF 50,000 Montaudo et al., 1994b PS none chloroform or THF 1400 Mowat & Donovan, 1995 PS HABA THF 46,000 Montaudo et al., 1995a PS dithranol AgtFAc 10,000 Scrivens et al., 1995 PS 9-Nitroanthracene THF 11,000 Lloyd et al., 1995 AgtFAc PS dithranol AgtFAc chloroform chloroform 40,000 Belu et al., 1996 PS dithranol AgtFAc THF THF 3500 Thomson et al., 1996 PS HABA THF THF 35,000 Liu & Schlunegger, 1996 PS 4-(Phenylazo)-resorcinol THF THF 35,000 Liu & Schlunegger, 1996 PS chromoionophor IV THF THF 35,000 Liu & Schlunegger, 1996 PS dithranol AgtFAc THF THF 7500 Chaudhary et al., 1996 PS IAA Agacac THF THF 125,000 Danis et al., 1996a PS POPOP Agacac THF THF 22,000 Danis et al., 1996a PS all-trans-Retinoic THF (puri®ed) THF (puri®ed) 1:5 MDa Schriemer & Li,
acid AgNO3 1996 PS dithranol AgtFAc THF THF 35,000 Schweer et al., 1996 PS dithranol cations THF THF 3000 Deery et al., 1996 PS dithranol AgtFAc 210,000 Lee & Han, 1996 PS all-trans-Retinoic THF THF 500,000 Brown et al., 1997
acid AgNO3 PS dithranol AgtFAc THF THF 200,000 Nielen & Malucha, 1997 65 PS dithranol Cu(acac)2 THF THF 7000 Burgers & Terlouw, 1998 PS dithranol Ag/Cu/Pd 4000 Rashidzadeh et al. 1998b
312 MALDI TOF MS OF SYNTHETIC POLYMERS &
TABLE 1. (Continued) Polymer Matrix Matrix solvent Polymer solvent MW Reference
PS, nitroxide- dithranol AgtFAc 5000 Beyou et al., 1998 PS, dedtc- dithranol AgtFAc 5000 Beyou et al., 1998 PS, macrocyclic- dithranol AgtFAc 4400 Pasch et al., 1997 PS, -methyl 9-nitroanthracene THF THF 1600 Kukulj et al., 1998 AgtFAc PVC IAA THF Danis & Karr, 1993 PVC HABA THF Danis & Karr, 1993 PVAc DHB methanol Danis & Karr, 1993 PVAc HABA acetone acetone Cornett et al., 1998 PC HABA THF 17,000 Montaudo et al., 1995a PC IAA THF Danis & Karr, 1993 PC HABA THF Danis & Karr, 1993 PC DHB chloroform 5000 Weidner et al., 1996b PC HABA 20,000 Montaudo et al., 1994c PC IAA THF THF 100,000 Nielen & Malucha, 1997 PC dithranol THF 5000 Pasch et al., 1996 PB none 1300 Mowat & Donovan, 1995 PB POPOP Agacac THF THF 11,000 Danis et al., 1996a
PB DHB AgNO3 THF THF 6000 Pastor & Wilkins, 1997 PB all-trans-Retinoic THF THF 300,000 Yalcin et al., 1997 acid Cu(II)nitrate PB, hydroxylated- dithranol AgtFAc THF THF 5000 Latourte et al., 1997a Polyisoprene all-trans-Retinoic acid THF THF 150,000 Yalcin et al., 1997 Cu(II)nitrate Polyisoprene dithranol AgtFAc THF THF Cornett et al., 1998 Squalane, Squalene NPOE AgtFAc toluene toluene 550 Weidner et al., 1997 Squalene, -epoxidized THAP ethanol/water 2000 Kuehn et al., 1997 Paraf®nes, Waxes DHB, NPOE ethanol/water toluene 3000 Kuehn et al., 1996 PDMS DHB THF 280,000 Montaudo et al., 1995b PMPS DHB THF THF 2500 Montaudo et al., 1996c PMPS IAA THF THF 2000 Montaudo et al., 1996c PMPS dithranol THF THF 2500 Montaudo et al., 1996c PAN 4-Hydroxy benzylidene acetone DMF 4500 Linnemayr et al., malononitrile 1998 Polycaprolactone HABA 14,000 Montaudo et al., 1994c Polycaprolactone HABA THF 10,000 Montaudo et al., 1995a Polycaprolactone DHB water LC mobile phase: THF 1400 Pasch & Rode, 1995 Polycaprolactone DHB methanol/water ethyl acetate 7000 Cordova et al., 1998 Polycaprolactone, DHB NaCl 5500 Miola et al., 1998 -benzyl/hydroxy PEF 2000 Hanton & Parees, 1995 PA6, -aminolized HABA 8000 Montaudo et al., 1994a (Continued)
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TABLE 1. (Continued) Polymer Matrix Matrix solvent Polymer solvent MW Reference
PA6, -diamino HABA tri¯uoroethanol 3000 Montaudo et al., 1995a PA6, -monoamino HABA tri¯uoroethanol 6200 Montaudo et al., 1995a PA6, -dicarboxyl HABA tri¯uoroethanol 6400 Montaudo et al., 1995a PA6 HABA tri¯uoroethanol 7000 Montaudo et al., 1996d polyamines, Triazine- DHB formic acid formic acid 5000 Braun et al., 1996 Poly(butylene adipate), HABA Montaudo et al., -glycolized 1994a Poly(butylene adipate) HABA THF 4000 Montaudo et al., 1995a Poly(butylene adipate) HABA, DHB THF 48,000 Montaudo et al., 1995d Poly(butylene adipate) IAA acetone acetone 3000 Williams et al., 1997 Poly(butylene adipate) dithranol AgtFAc THF THF 6500 Liu & Schlunegger, 1996 Poly(decamethylene DHB water THF/hexane (45:55) 3000 Pasch & Rode, 1995 adipate) Poly(ethylene DHB, THAP chloroform 3500 Weidner et al., 1995 terephtalate) Poly(ethylene DHB 5±10 mg/mL chloroform 3000 Weidner et al., terephtalate) 1996a Poly(ethylene DHB chloroform Weidner et al., terephtalate) 1996b Poly(ethylene 3000 Yates et al., 1996 terephtalate) Poly(ethylene dithranol THF HFIP 4000 Jackson A et al., terephtalate) 1997a Polyester, -aliphatic, DHB, IAA water±methanol, THF water, THF, THF/TFA, TFA 8000 Blais et al., 1995 -aromatic Poly(trimethylene IAA 4800 Williams et al., 1995 glutarate) Poly(trimethylene IAA acetone acetone 3000 Williams et al., 1997 glutarate) Poly(trimethylene IAA acetone acetone 3000 Williams et al., 1997 adipate) Poly(trimethylene IAA acetone acetone 3000 Williams et al., 1997 succinate) Polyester DHB THF, acetone THF, acetone 5000 Guittard et al., 1996b Poly(ethylene DHB THF 4000 Pasch et al., 1996 terephtalate, -isophtalate) Poly(dihydroxymethyl- HABA THF THF 120,000 Scampporrino et al., benzene/phtalate) 1996 Poly(neopentyl IAA THF THF 40,000 Nielen & Malucha, terephtalate) 1997 Poly(ethylene adipate) IAA acetone acetone 3000 Williams et al., 1997 Poly(neopentyl sebacate) IAA acetone acetone 3000 Williams et al., 1997 Polyester, -methylated 5-nitrosalicylic acid 2500 Guittard et al., 1997 Polyester, -cyclic 5-CSA 8000 Guittard et al., 1996a Poly(diethyl- DHB water/acetonitrile acetone 2000 Feast et al., 1997 3-hydroxyglutarate) Poly(phenylglycidyl- DHB ethanol THF 6000 Leukel et al., 1996 phtalic anhydride)
314 MALDI TOF MS OF SYNTHETIC POLYMERS &
TABLE 1. (Continued) Polymer Matrix Matrix solvent Polymer solvent MW Reference
Poly(hydroxystearate) IAA THF Danis & Karr, 1993 Dendrimers, -aromatic DHB water/acetone water/acetone, chloroform, 5200 Sahota et al., 1994 polyester sodium chloride Dendrimers, -aromatic IAA THF THF 14,000 Leon & Frechet, polyether 1995 Dendrimers IAA acetone THF, chloroform Milberg & Garden, 1996 Dendrimers all-trans-Retinoic acid methylene chloride THF, chloroform >20,000 Milberg & Garden, 1996 Dendrimers, -carbosilane, DHB water Wu & Biemann, -t-amino 1997 Dendrimers, -carbosilane, DHB ammonium citrate water Wu & Biemann, -sulfonated (1:1) 1997 Dendrimers, IBU- dithranol THF THF 11,000 Srinivasan et al., 1998 Dendrimers, -aromatic- benzyloxycyano-cinnamic 5000 Gooden et al., 1998 polyether acid PU HABA 10,000 Tang et al., 1995a PU, -pyrolysate 5500 Lattimer, 1998 PU, dendritic wedges CHCA acetone acetone 6500 Puapaiboon & Taylor, 1999 PI dithranol AgtFAc chloroform chloroform 5000 Belu et al., 1996 Polysul®de, -linear 9-Nitroanthracene THF THF 2800 Mahon et al., 1998 AgtFAc PAA Danis et al., 1992 PAA, -¯uorinated end DHB THF THF 2000 Latourte et al., 1997b PSS SA 180,000 Danis et al., 1992 PSS DHB, SA, CSA water, water, THF 100,000 Raeder et al., 1995 PSS SA water 450,000 Danis & Karr, 1995 Polylactide DHB THF THF 6000 Montaudo et al., 1996b Polylactide HABA THF THF 10,000 Montaudo et al., 1996b Polydextrane DHB/HIC (3:1) water/acetonitrile water 2000 Bornsen et al., 1995
Copolymers and resins PVP/PVAc IAA THF Danis & Karr, 1993 PVP/PVA 3500 Schaer, 1995 EO/PO DHB water acetonitrile±water 1400 Pasch & Rode, 1995 EO/PO Kalinoski et al., 1995 EO/PO dithranol HFIP HFIP Scrivens et al., 1998 PO/EO/PO, HABA dioxane 2000 Schriemer & Li, -diaminopropylether 1995 EO/PO/EO, PO/EO/PO CHCA potassium iodide 8600 Lacey et al., 1996 EO/pyrene HABA 1,4-dioxane methanol 10,000 Lee et al., 1996 Jeffamine ACA/MSA ethanol methanol 2000 Tang et al., 1995b Jeffamine HABA dioxane dioxane 3000 Schriemer et al., 1997 Jeffamine DHB methanol methanol Goldschmidt & Owens, 1997 PPE-b-PEO dithranol THF 3500 Francke et al., 1998 PS/PMeS IAA AgIAA THF THF 5000 Wilczek-Vera et al., 1996 PMMA/MeSTY, IAA acetone acetone 9000 Guttman et al., 1997 -block(SRM 1487) (Continued)
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TABLE 1. (Continued) Polymer Matrix Matrix solvent Polymer solvent MW Reference
PMMA/PBMA DHB acetone THF 2500 Suddaby et al., 1996 PMMA/PBMA DHB acetone 4500 Haddleton et al., 1997 PMMA/PMAA IAA THF THF 150,000 Nielen & Malucha, 1997 PDMS/PHMS NPOE THF THF 15,000 Servaty et al., 1998 Copoly(aryletherketone/ dithranol chloroform chloroform 4000 Wang et al., 1997 arylethersulfone), -cyclic Copoly(arylether/ether dithranol AgtFAc 6000 Wang & Hay, 1997 sul®des) Copolycarbonate/copper HABA THF THF 3000 Vitalini et al., 1996 complex Copolyether-bisphenolA/ HABA THF THF 4000 Vitalini et al., 1996 copper complex Copolybisphenol HABA 1,4-dioxane dioxane 10,000 Schriemer et al., A/epichlorohydrin 1997 Copolyester PBA/PBS HABA, DHB THF 80,000 Montaudo et al., 1995d Copolyester PBA/PBSe HABA THF/chloroform SEC fraction THF or 30,000 Montaudo et al., chloroform 1998a Copolyester PBSu/PBA HABA THF/chloroform SEC fraction THF or 30,000 Montaudo et al., chloroform 1998a Copolyester PBSu/PBSe HABA THF/chloroform SEC fraction THF or 30,000 Montaudo et al., chloroform 1998a Copolyester HABA THF/chloroform SEC fraction THF or 30,000 Montaudo et al., PBSu/PBA/PBSe chloroform 1998a Copolyester HABA THF/chloroform chloroform 15,000 Montaudo et al., 1998c Epoxy resin DHB acetone acetone 3500 Epoxy resin, DHB SEC fractions 6000 Lo & Huang, 1998 -thiodiphenol Poly(cresylglycidyl/ 1,3-diphenylbutadiene acetone 2800 Schriemer & Li,
formaldehyd) AgNO3 1995 Poly(cresylglycidyl/ 1,4-diphenylbutadiene acetone acetone 3500 Schriemer et al.,
formaldehyde) AgNO3 1997 PF resin, -epoxy DHB acetone 2000 Pasch et al., 1996 PF resin DHB acetone 4000 Pasch et al., 1996 PF resin, -alkyl dithranol chloroform chloroform 2000 Mandal & Hay, 1997b PF resin, -polycyclic 2700 Mandal & Hay, carbonate of- 1997a PF resin, t-Butyl-, cyclic dithranol AgtFAc chloroform THF chloroform 2500 Mandal & Hay, siloxanes 1998a PF resin, Phenyl-, dithranol AgtFAc chloroform THF chloroform 2500 Mandal & Hay, cyclic siloxanes 1998a PF resin, -cyclic dithranol chloroform chloroform 2700 Mandal & Hay, phosphonate 1998b
Miscellaneous Fullerene CHCA benzene benzene 800 Cordero et al., 1996 Fullerenes MSA 756 Rogner et al., 1996 Fullerenes CHCA acetone chloroform Linnemayr & Allmaier, 1997 Fullerenes sulfur carbon disul®de 992 Brune, 1999 Calixarenes HPA water/acetonitrile chloroform Linnemayr & Allmaier, 1997
316 MALDI TOF MS OF SYNTHETIC POLYMERS &
TABLE 1. (Continued) Polymer Matrix Matrix solvent Polymer solvent MW Reference
Calix[3]indoles SA dichloromethane 1200 Lidgard et al., 1996
Triton X305 K4[Fe(CN)6]/glycerol chloroform 2000 Zollner et al., 1996 Tween 85 HABA acetonitrile/water acetonitrile/water 2000 Giang & Chang, 1997 Tween 20 CHCA acetonitrile/water water or isopropanol 2000 Cumme et al., 1997 Sorbitols, methyl, FA Kim et al., 1998 benzylidene- Surfynol DHB methanol methanol 1600 Parees et al., 1998 Alkylphenolethoxylate, DHB methanol 1000 Barry et al., 1997 -derivatized Surfactants, -ethoxylated CHCA ethanol iso-propanol or water 1800 Bartsch et al., 1998 Azodyes, polysulfonated- HABA diammonium ethanol water 1400 Sullivan & Gaskell, citrate 1997
TABLE 2. Physical-chemical data of UV±MALDI matrices