Experiment and theory confirm that UV laser photodissociation spectroscopy can distinguish protomers formed via electrospray

TY - JOUR

T1 - Experiment and theory confirm that UV laser photodissociation spectroscopy can distinguish protomers formed via electrospray

AU - Matthews, Edward

AU - Dessent, Caroline E H

N1 - This is an author-produced version of the published paper. Uploaded in accordance with the publisher’s self-archiving policy. Further copying may not be permitted; contact the publisher for details

PY - 2017/7/14

Y1 - 2017/7/14

N2 - The identification of protonation sites in electrosprayed molecules remains a challenge in contemporary physical science. We present the first demonstration that low-resolution, UV laser photodissociation spectroscopy can be applied in situ to identify the protomers of para-aminobenzoic acid (PABA) formed via electrospray from a single solution. Electronic absorption spectra are recorded via photodepletion and photofragmentation for PABA electrosprayed from solutions of water and acetonitrile. Using this approach, two protomers can be straightforwardly identified, with only the carboxylic acid protomer being produced on electrospray from water while the amine-protonated isomer dominates upon electrospray from acetonitrile. High-level SORCI and MRCI calculations are presented to provide insight into the origin of the distinctive electronic spectra displayed by the protomers. Our results are in excellent agreement with previous PABA studies conducted using established techniques, and demonstrate that UV photodissociation spectroscopy of electrosprayed ions has potential as a new diagnostic tool for identifying protomeric species.

AB - The identification of protonation sites in electrosprayed molecules remains a challenge in contemporary physical science. We present the first demonstration that low-resolution, UV laser photodissociation spectroscopy can be applied in situ to identify the protomers of para-aminobenzoic acid (PABA) formed via electrospray from a single solution. Electronic absorption spectra are recorded via photodepletion and photofragmentation for PABA electrosprayed from solutions of water and acetonitrile. Using this approach, two protomers can be straightforwardly identified, with only the carboxylic acid protomer being produced on electrospray from water while the amine-protonated isomer dominates upon electrospray from acetonitrile. High-level SORCI and MRCI calculations are presented to provide insight into the origin of the distinctive electronic spectra displayed by the protomers. Our results are in excellent agreement with previous PABA studies conducted using established techniques, and demonstrate that UV photodissociation spectroscopy of electrosprayed ions has potential as a new diagnostic tool for identifying protomeric species.

KW - Journal Article

UR - http://www.scopus.com/inward/record.url?scp=85024494685&partnerID=8YFLogxK

U2 - 10.1039/c7cp02817b

DO - 10.1039/c7cp02817b

M3 - Article

C2 - 28650510

SN - 1463-9076

VL - 19

SP - 17434

EP - 17440

JO - Physical chemistry chemical physics : PCCP

JF - Physical chemistry chemical physics : PCCP

IS - 26

ER -