Abstract：
Rapid, efficient, versatile, easy-to-use, and non-expensive analytical approaches are globally demanded for food analysis. Many ambient ionization approaches based on electrospray ionization (ESI) have been developed recently for the rapid molecular characterization of food products. However, those approaches mainly suffer from insufficient signal duration for comprehensive chemical characterization by tandem MS analysis. Here, a commercially available disposable gel loading tip is used as a low-cost emitter for the direct ionization of untreated food samples. The most important advantages of our approach include high stability, and durability of the signal (> 10 min), low cost (ca. 0.1 USD per run), low sample and solvent consumption, prevention of tip clogging and discharge, operational simplicity, and potential for automation. Quantitative analysis of sulfapyridine, HMF (hydroxymethylfurfural), and chloramphenicol in real sample shows the limit-of-detection 0.1 μg mL-1, 0.005 μg mL-1, 0.01 μg mL-1; the linearity range 0.1-5 μg mL-1, 0.005-0.25 μg mL-1, 0.01-1 μg mL-1; and the linear fits R2 ≥ 0.980, 0.991, 0.986. Moreover, we show that tip-ESI can also afford sequential molecular ionization of untreated viscous samples, which is difficult to achieve by conventional ESI. We conclude that tip-ESI-MS is a versatile analytical approach for the rapid chemical analysis of untreated food samples.
摘要：
快速，高效,多才多艺，易于使用，和非昂贵的分析方法是全球需要食品分析。最近已经开发了许多基于电喷雾电离（ESI）的环境电离方法，用于食品的快速分子表征。然而,这些方法主要受到通过串联MS分析进行全面化学表征的信号持续时间不足的困扰。这里,商业上可获得的一次性凝胶装载尖端用作用于未处理的食物样品的直接电离的低成本发射器。我们的方法最重要的优点包括高稳定性，和信号的耐久性（>10分钟），低成本(约每次运行0.1美元)，低样品和溶剂消耗，防止尖端堵塞和排出，操作简单，和自动化的潜力。磺胺吡啶的定量分析，HMF(羟甲基糠醛),实际样品中氯霉素的检出限为0.1μgmL-1、0.005μgmL-1、0.01μgmL-1；线性范围为0.1-5μgmL-1、0.005-0.25μgmL-1、0.01-1μgmL-1；线性拟合R2≥0.980、0.991、0.986。此外，我们表明，tip-ESI还可以提供未处理的粘性样品的顺序分子电离，这是传统的ESI难以实现的。我们得出的结论是，tip-ESI-MS是一种用于快速化学分析未经处理的食品样品的通用分析方法。
