title: Elemental quantitation of carbon via production of polyatomic anions in gas chromatography-plasma assisted reaction chemical ionization mass spectrometry.
abstract: Elemental mass spectrometry offers quantitation and isotopic analysis without the need for compound-specific standards. We have recently introduced plasma assisted reaction chemical ionization (PARCI) as an efficient elemental ionization method for halogens. Here, we report a new ionization chemistry in PARCI for facile quantitation of elemental carbon in gas chromatography eluates. We demonstrate that in-plasma reactions of organic compounds followed by afterglow ionization lead to formation of polyatomic anions (CN-, OCN-, and CO3-), among which CN-offers the best analytical sensitivity with a detection limit of ~25 pg (21 pg/s) carbon on column. Using a mixture of pesticides with wide variations in structures and heteroatom content, we demonstrate that CN-ion response is quantitatively correlated with the carbon concentration over two orders of magnitude (r2= 0.985). We show that the novel GC-PARCI-MS method provides recoveries within 80-120% using a single standard for all analytes, highlighting the strength of elemental quantitation. Further, the ability of GC-PARCI-MS to identify13C-tagged molecules without a priori knowledge of chemical formulas of analytes is demonstrated. Graphical abstract ᅟ.
authors.affiliation: Department of Chemistry, Georgetown University, Washington, DC, 20057, USA.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Haferl
authors.affiliation: Department of Chemistry, Georgetown University, Washington, DC, 20057, USA.
authors.forename: Kunyu
authors.initials: K
authors.lastname: Zheng
authors.affiliation: Department of Chemistry, Georgetown University, Washington, DC, 20057, USA.|Agilent Technologies Inc., Santa Clara, 95051, CA, USA.
authors.forename: Haopeng
authors.initials: H
authors.lastname: Wang
authors.affiliation: Department of Chemistry, Georgetown University, Washington, DC, 20057, USA. kj256@georgetown.edu.
authors.forename: Kaveh
authors.initials: K
authors.lastname: Jorabchi
keywords: Carbon; Compound-independent calibration; Elemental quantitation; Isotopic tagging; Mass spectrometry