Extractive Atmospheric Pressure Photoionization (EAPPI) Mass Spectrometry: Rapid Analysis of Chemicals in Complex Matrices

Abstract

Abstract. Extractive atmospheric pressure photoionization (EAPPI) mass spectrometry was designed for rapid qualitative and quantitative analysis of chemicals in complex matrices. In this method, an ultrasonic nebulization system was applied to sample extraction, nebulization, and vaporization. Mixed with a gaseous dopant, vaporized analytes were ionized through ambient photon-induced ion-molecule reactions, and were mass-analyzed by a high resolution time-of-flight mass spectrometer (TOF-MS). After careful optimization and testing with pure sample solution, EAPPI was successfully applied to the fast screening of capsules, soil, natural products, and viscous compounds. Analysis was completed within a few seconds without the need for preseparation. Moreover, the quantification capability of EAPPI for matrices was evaluated by analyzing six polycyclic aromatic hydrocarbons (PAHs) in soil. The correlation coefficients (R 2 ) for standard curves of all six PAHs were above 0.99, and the detection limits were in the range of 0.16-0.34 ng/mg. In addition, EAPPI could also be used to monitor organic chemical reactions in real time.

High-throughput screening of PAHs and polar trace contaminants in water matrices by direct solid-phase microextraction coupled to a dielectric barrier discharge ionization source

“…For example, previous reports of LODs based on LC-DBDI-MS were in the low ng/mL range [28]. Other ambient techniques such as DART [34] and the atmospheric solids analysis probe (ASAP) [35] are also limited to detection in the mid to low ng mL -1 range, and even techniques which should be more suitable for the analysis of PAHs, such as extractive atmospheric pressure photoionization (EAPPI), reported LODs (0.16-0.34 ng mL -1 ) [36] higher than the values obtained in this study (0.1 ng mL - Figure 7). It must be pointed out that the levels at which these compounds were detected were low, with DEET present at 30 pg mL -1 , and all other compounds present below the LOQ (defined at S/N = 10).…”

Fast and comprehensive characterization of chemical ingredients in traditional Chinese herbal medicines by extractive atmospheric pressure photoionization (EAPPI) mass spectrometry

“…Figure 1A shows the schematic of the EAPPI source, which has been described in detail elsewhere. 27 The EAPPI source combined APPI and an ultrasonic nebulization system, which included an ultrasonic 3 | RESULTS AND DISCUSSION…”

“…24 There have been several well-established ambient mass spectrometry methods derived from APPI, such as desorption APPI 25 and laser ablation APPI. 26 Extractive APPI (EAPPI), 27 a novel method developed for the fast analysis of compounds in complex matrices, was employed here as the first APPI-based ambient method for the direct analysis of constituents in TCHMs systematically.…”

Scale-up of microdroplet reactions by heated ultrasonic nebulization

“…41 Since then, UN has been used commercially in air humidiers, medical nebulizers, and other such devices. UN has also been used as a method of sample atomization for subsequent ionization such as inductively coupled plasma, 42,43 electrospray ionization (ESI), 44,45 extractive electrospray ionization, 46 and photoionization 47,48 in MS. Ultrasonically generated microdroplets have also been used as microreactors for the synthesis of semiconductor nanoparticles, 49 porous carbon powder, 50 and other nanostructured materials. 51 Ambient ionization MS was even applied for the real-time monitoring of microreactions in acoustically levitated droplets for which at least an order of magnitude faster reaction rate was observed.…”