Direct Analysis of Carbonyl Compounds by Mass Spectrometry with Double-Region Atmospheric Pressure Chemical Ionization

Abstract

Direct analysis of highly reactive volatile species such as the aliphatic aldehydes as vital biomarkers remains a great challenge due to difficulties in the sample pretreatment. To address such a challenge, we herein report the development of a novel double-region atmospheric pressure chemical ionization mass spectrometry (DRAPCI-MS) method. The DRAPCI source implements a separated structural design that uses a focus electrode to divide the discharge and ionization region to reduce sample fragmentation in the ionization process. Counterflow introduction (CFI) configuration was adopted in the DRAPCI source to reduce background noise, while ion transmission efficiency was optimized through simulating the voltage of the focus electrode and the ion trajectory of the ion source. The limits of detection (LODs) of four carbonyl compounds cyclohexanone, hexanal, heptanal, and octanal by DRAPCI-MS were between 0.1 and 3 μg·m–3, approximately two to eight times lower than those by atmospheric pressure chemical ionization mass spectrometry. Additionally, the DRAPCI-MS method carried out effective in situ analyses of the volatile components in expired milk and the exhaled breath of smokers, demonstrating the DRAPCI-MS as a practical tool to analyze complex mixtures. The DRAPCI-MS method provides a rapid, sensitive, and high-throughput technique in the real-time analysis of gaseous small-molecule compounds.

Self-aspiration sampling design for rapid analyses of volatile organic compounds based on atmospheric pressure chemical ionization/photoionization combined ionization source mass spectrometry

“…Through the modification of a mass spectrometry injection system, the negative-pressure injection of an APCI source was realized using the Venturi effect, and a method to detect acrolein and crotonaldehyde by water-assisted ionization was devoloped. 35 We designed a novel double-region atmospheric pressure chemical ionization (DRAPCI) 36 source to realize the online determination of carbonyl compounds in food and exhaled-gas analysis. Low-molecular-weight aldehydes in beer have been investigated using online derivatization to improve aldehyde detection.…”

Portable Digital Linear Ion Trap Mass Spectrometer Based on Separate-Region Corona Discharge Ionization Source for On-Site Rapid Detection of Illegal Drugs

“…Corona discharge ionization source has been widely used as a type of atmospheric pressure chemical ionization (APCI) [ 24 , 25 , 26 , 27 , 28 ], which is essentially an ion-molecule reaction in the gas phase. Therefore, the sample introduction method needs to turn the target analyte into the gas-phase.…”

Real-Time Sniffing Mass Spectrometry Aided by Venturi Self-Pumping Applicable to Gaseous and Solid Surface Analysis

“…2−4 The utility of MS as a diverse technique is validated by various applications, such as the detection of compounds of interest in exhaled breath by gas chromatog-raphy MS 5 and the ability of inductively coupled plasma MS for metallic compound gas detection. 6 In related studies, detection of gaseous components in trace amounts has been performed by real-time MS techniques such as proton-transferreaction MS, 7 selective ion flow tube MS, 8 extractive electrospray ionization MS, 9,10 and APCI-MS. 11 concentrations (down to ppt levels) by a literal "sniff" or "smell". The aforementioned technique is aptly termed as "sniffing MS", 12 wherein components in the vapor phase are aspired to a regular ionization source for subsequent identification by MS.…”

“…Various relatively complex MS studies based on sample introduction via the Venturi self-aspirating effect involving either the electrospray ionization (ESI) MS or atmospheric pressure chemical ionization (APCI) MS technique have been proposed. − The utility of MS as a diverse technique is validated by various applications, such as the detection of compounds of interest in exhaled breath by gas chromatography MS and the ability of inductively coupled plasma MS for metallic compound gas detection . In related studies, detection of gaseous components in trace amounts has been performed by real-time MS techniques such as proton-transfer-reaction MS, selective ion flow tube MS, extractive electrospray ionization MS, , and APCI-MS . We have recently introduced a new and versatile MS technique for the detection of various gaseous components at exceedingly low concentrations (down to ppt levels) by a literal “sniff” or “smell”.…”