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To figure out the reason for the drawback of the stored waveform inverse Fourier transform (SWIFT) waveform and realize the high-resolution ion isolation on the miniaturized linear ion trap mass spectrometer, we studied the efficiency that ions can be excited under different excitation durations and amplitudes at different frequencies and compared the overlap ratios of the effective excitation frequency bandwidths of the adjacent ions. According to this, we proposed a new coarse-to-fine isolation waveform named SWIFTSIN. By superposing one or more sinusoidal waveforms on the SWIFT waveform and modulating the phases of the superposed sinusoidal waveforms, the generated SWIFTSIN waveform can achieve unit mass isolation on the miniaturized linear ion trap mass spectrometer without reducing the intensity of the target ion. The isolation ability of the SWIFTSIN waveform was verified by isolating a single isotope peak in the mixed samples.

Inverse kinematics for all joint motions of parallel robot is the foundation for stiffness or dynamic analysis, and the prerequisite for motion monitoring during operation in case of collision or damage. The software equipped with a generalized inverse kinematic method is beneficial for the efficient motion solving of different parallel robots, and especially convenient for kinematic control development. Current inverse kinematic methods are either case-by-case studies or not amicable for programming. To tackle these problems, this paper proposes a generalized method to determine all the joint motions of parallel robot based on finite screw theory, including mechanism initialization, kinematic modeling and kinematic variable solving. Two parallel robots are taken as examples to verify the effectiveness and accuracy of the approach. After that, the method is applied for digital programming on the basis of computer technology, and a software is developed for the automatic inverse kinematic analysis. The advantages of this method lie in: the kinematic equation could be formulated in a general and concise manner independence of experience and observation; all the joint variables under given target pose are solved at the same time; it enables easy programming and realizes the automation of inverse kinematic analysis.

With the expansion of the functional food market, the qualification assessment of these products has become a major challenge, and efficient analytical tools are urgently needed. Here, a miniature mass spectrometer (MS) with self-aspiration capillary electrospray ionization (SACESI) source and ion trap analyzer was developed for rapid screening of various illegally added drugs in functional foods. No chromatographic separation was required, but a simplified two-step pretreatment method was developed to reduce the operational procedures and time consumption of the entire analysis. SACESI source uses capillary action to drive solution injection, which utilizes a simple structure and convenient operation to constitute a kind of disposable MS detection solution. To achieve accurate and automatic identification, an intelligent recognition algorithm with steps of spectrum preprocessing, characteristic peak matching, and support vector machine learning was constructed. The relative accuracy of rapid screening of 31 suspicious drugs in various samples is up to 99.78%. It achieves 100% correct identification for the 55 batches of actual samples captured by on-site inspection, which demonstrates the feasibility of the proposed analytical system and strategy in food safety applications.

This work reported an air atmospheric pressure plasma jet served as an ion source for nonvolatile solid analysis, which allows a unique capability to achieve thermal desorption and ionization simultaneously without complex devices, inert gas, or solvents. Owing to precise amount of heat generated by plasma jet, nonvolatile analytes were thermally released from solid surfaces without the assistance of secondary desorption equipment. According to the mass spectra and Fourier transform infrared spectrum, [M + H]+ and [M + NO3]− ions were the major analyte ions in the positive-ion and negative-ion modes, respectively. The applied voltages, discharge currents, and gas temperatures of plasma jet were measured, and found to be positively correlated with the mass spectra signal intensity of the samples, while the added resistances and gas flow rate were negatively correlated with the signal intensity. The influence mechanisms of analytes natures coupling physical parameters of plasma jet on detection performance were revealed. The prospect of quantitative testing was confirmed by the linear relationship between the peak intensity and sample mass.

In recent years, the development of unsaturated lipid isomeric imaging based on the Paterno–Buchi (PB) reaction has improved significantly. However, research on this imaging method in ambient conditions needs to expand. In this paper, a method of PB reaction in the solid phase in ambient conditions is developed, which is combined with air-flow-assisted desorption electrospray ionisation mass spectrometry (AFADESI-MS) to achieve in situ imaging of lipids at an isomeric level. Experiments showed that the efficiency of the PB reaction was much higher when spraying the reagent solution than when sprinkling the reactant powder directly, and it was not lower than that in the liquid phase. This method can simplify the reaction conditions in the imaging process and can be applied to tissue section samples with only 10 min of pre-processing. The study successfully demonstrated the spatial distribution of unsaturated lipid isomers, and the isomeric ratio corresponded to the lesion areas in mouse brain cancer tissues. Due to its simple operation and performance in ambient conditions, this method may be useful for future studies on lipid isomers in tissues.