Generating Electrospray Ionization on Ballpoint Tips

In this study, we report a simple and economical ballpoint electrospray ionization mass spectrometry (BP-ESI-MS) technique. This combines a small ballpoint tip with a syringe pump for the direct loading and ionization of various samples in different phases (including solution, semisolid, and solid) and allows for additional applications in surface analysis. The tiny metal ball on the ballpoint tip exhibits a larger surface for ionization than that of a conventional sharp tip end, resulting in higher ionization efficiency and less sample consumption. The adamant properties of the ballpoint tip allow sampling by simply penetrating or scraping various surfaces, such as a fruit peel, paper, or fabric. Complex samples, such as fine herbal powders and small solid samples, could be stored in the hollow space in the ballpoint socket and subsequently extracted online, which greatly facilitated MS analysis with little to no sample preparation. Positive ion mode was attempted, and various compounds, including amino acids, carbohydrates, flavonoids, and alkaloids, were detected from different types of samples. The results demonstrated that the special and excellent physical characteristics of ballpoint tips allowed for fast and convenient sampling and ionization for mass spectrometry analysis by the BP-ESI-MS method

Determination of Sulfonamides in Chicken Muscle by Pulsed Direct Current Electrospray Ionization Tandem Mass Spectrometry

A simple and rapid approach for the simultaneous detection of trace amounts of six sulfonamides in chicken muscle was developed using pulsed direct current electrospray ionization tandem mass spectrometry (pulsed-dc ESI-MS/MS). The pretreatment of chicken muscle samples consisted of two steps: acetonitrile extraction and <i>n</i>-hexane delipidation. Sulfonamides do not need to be derivatized or chromatographed prior to pulsed-dc ESI-MS/MS. The factors affecting the performance of pulsed-dc ESI-MS/MS were studied. Under optimum conditions, the quantitative performance of pulsed-dc ESI-MS/MS was validated according to European Union Decision 2002/657/EC, and the sensitivity of pulsed-dc ESI-MS/MS was 3 times higher than that of ultrahigh-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The limits of detection obtained by pulsed-dc ESI-MS/MS were in the range of 0.07–0.11 μg/kg. The proposed method was simple, rapid, and sensitive, and was successfully used for quantitation and rapid screening of sulfonamides in real chicken muscle samples