Nanoliter atmospheric pressure photoionization-mass spectrometry for direct bioanalysis of polycyclic aromatic hydrocarbons.

Polycyclic aromatic hydrocarbons (PAHs) are a class of low-polarity environmental contaminants that have severe carcinogenic effects and have drawn worldwide attention. However, there remain challenges for current mass spectrometric ionization techniques in the analysis of low-polarity compounds in small-volume biosamples, such as single cells. In this work, we developed a nanoliter atmospheric pressure photoionization (nano-APPI) source and optimized its parameters for the detection of PAHs in small-volume samples.

Investigation on the binary ionization choices for large conjugated amines during electrospray ionization.

Rationale: Generally, amines form protonated cations ([M + H] ) in positive polarity during electrospray ionization (ESI). However, it was found that large conjugated amines (LCAs) had binary ionization choices of generating either radical cations (M ) or [M + H] during ESI. Investigation on the mechanism would further our understanding of ESI.

Direct analysis of hydroxylated polycyclic aromatic hydrocarbons in biological samples with complex matrices using polarity-reversed nanoelectrospray ionization.

Rationale: Polycyclic aromatic hydrocarbons (PAHs) are a class of environmental contaminants with carcinogenic effect drawing worldwide attention. PAHs can be converted into hydroxylated PAHs (OH-PAHs) through metabolic processes. Thus, they are commonly considered as an important class of biomarkers of PAH exposure.