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With the goal of enhancing the low sensitivity of the conventional atmospheric pressure chemical ionization (APCI) source due to the ion divergence, here is reported a T-shaped ion source to improve the sensitivity with a portable mass spectrometer for the rapid determination of the pesticides ethoprophos and atrazine in water. Compared with conventional APCI, the ion source improves the sensitivity for the analytes. The results show that the analysis requires less than 2 s, the limit of detection (LOD) is better than 0.1 μ g · mL − 1 , and the relative standard deviation (RSD) is 16% at 1, 5, and 25 μ g · mL − 1 . The recoveries of the analytes are between 80% and 130%, meeting the requirements for rapid pesticide determination in water. [ABSTRACT FROM AUTHOR]

With the increasing prevalence of illicit drugs, social security and human health are at serious risk. However, traditional detection techniques require a lengthy pretreatment process to eliminate matrix interference and do not allow rapid, in situ analysis. Ambient ionization is a powerful tool for the rapid determination of illicit drugs in different matrices because it usually eliminates the need for sample pretreatment, and the portable mass spectrometer brings convenience to in situ detection. This study employed a thermal desorption-electrospray ionization (TD-ESI) source combined with a portable mass spectrometer to rapidly characterize illicit drugs in drinks, instant powders, and solid food surfaces. Air was utilized instead of nitrogen as the carrier gas for TD-ESI/MS in order to save space and cost together with rapid on-site analysis. A full-scan waveform combined with a qualitative pre-scan waveform (QPSW) was employed to form a two-step scanning mode to accurately identify the drugs. The results showed that the limits of detection (LODs) for the analytes were 100–200 ppb in drinks, 700–1000 ppb in instant powders, and 1 ng/cm2 on solid food surfaces. The complete TD-ESI/MS analysis time was less than 1 min. [ABSTRACT FROM AUTHOR]

While portability is a key aspect of small mass spectrometers, they also need to be able to effectively screen the analytes from complex matrices. The accuracy and performance of mass spectrometers depend not only on the identification of parent ion signals in targets but also fragment ion signals. This paper reports on the construction of a device that uses a new time-domain excitation waveform called qualitative pre-scan waveform (QPSW) for its quadrupole ion trap mass spectrometry analyzer. This approach uses scanning to eliminate interfering ions, thus improving the sensitivity for the analyte and removing the cumbersome steps required to convert conventional stored waveform inverse Fourier transform (SWIFT) waveforms from the frequency domain to the time domain. Tests show that the target ions can be fragmented just by introducing air at the moment when the pinch valve is opened without any need for a carrier gas. This simplifies the equipment required, making the mass spectrometer more portable. Tests were undertaken to compare the performance with the use of conventional SWIFT waveforms and to optimize its experimental parameters so that the target ions were effectively accumulated in the ion trap. An approximate 5-fold improvement in sensitivity was achieved by QPSW compared to the SWIFT for 2 μg/mL ketamine. A 5-fold reduction in the limit of detection (LOD) to 20 ng/mL was also obtained for enrofloxacin. In addition, the stability was improved by QPSW with a relative standard deviation less than 13% compared to 16% for SWIFT. [ABSTRACT FROM AUTHOR]