Direct desorption/ionization of analytes by microwave plasma torch for ambient mass spectrometric analysis

Abstract

Ambient ionization is the new revolution in mass spectrometry (MS). A microwave plasma produced by a microwave plasma torch (MPT) at atmospheric pressure was directly used for ambient mass spectrometric analysis. H3O(+) and NH4(+) and their water clusters from the background are formed and create protonated molecules and ammoniated molecules of the analytes. In the full-scan mass spectra, both the quasi-molecular ions of the analytes and their characteristic ionic fragments are obtained and provide evidence of the analyte. The successful detection of active compounds in both medicine and garlic proves that MPT has the efficient desorption/ionization capability to analyze solid samples. The obtained decay curve of nicotine in exhaled breath indicates that MPT-MS is a useful tool for monitoring gas samples in real time. These results showed that the MPT, with the advantages of stable plasma, minimal optimization, easy, solvent-free operation, and no pretreatment, is another potential technique for ambient MS.

Comparative study on ambient ionization methods for direct analysis of navel orange tissues by mass spectrometry

“…A high abundance of ammonium adducted ions (e.g. [glucosan + NH 4 ] + ( m / z 180) and [glucose/fructose + NH 4 ] + ( m / z 198)) were obtained by MPT‐MS, which could be rationalized by the existence of NH 4 + and its water clusters in the plasma . Moreover, chemicals including glucosan ([2 M + H] + ( m / z 325) and [2 M + NH 4 ] + ( m / z 342)), tetramethyl‐ O ‐scutellarein ([M + H] + ( m / z 343)), citrunobin ([M + H] + ( m / z 353)), sinensetin ([M + H] + ( m / z 373)), sucrose ([M + K] + ( m / z 381), [M + H 2 O + H] + ( m / z 399)), nobiletin ([M + H] + ( m / z 403)) and 3,5,6,7,8,3′,4′‐heptamethoxyflavone ([M + H] + ( m / z 433)) were obtained (Fig.…”

Ambient ionization and direct identification of volatile organic compounds with microwave‐induced plasma mass spectrometry

“…Ammonium adduct ions could be another proton source. The possibility of the formation of ammonium in microwave plasma has been described in literature . Another ion observed in lower abundance is O 2 H + , formed in endothermic ion/molecule reactions .…”

Exhaled Breath Analysis of Smokers Using CMV-GC/MS

“…One female reported an age within the [26][27][28][29][30][31][32][33][34][35] age range and two males reported in the 18-25 age range were recruited. Details of the study were described to the individuals, stressing the importance of breath sampling occurrence within one hour of a completed smoking session.…”

“…As smoking habits of individuals strongly influence their exhaled breath [28,35,75] have been able to demonstrate that nicotine is detectable in breath and e-cig respectively after a single exhalation [24,77]. These research studies examining nicotine concentration during particular detection windows depend on the available amount of nicotine for exhalation.…”

“…Nicotine is available for excretion in exhaled breath because during the absorption process of nicotine diffusion into the surface fluid of the epithelium, some of the nicotine vapors are lost [79]. Given this information regarding the availability of nicotine in exhaled breath, studies were able to detect nicotine in breath 20 minutes [28] and even 70 minutes [62] after smoking dosages by cigarette. Even the metabolite cotinine has been reported as detectable in exhaled breath 1 hour after nicotine dosage by cigarette [76].…”