| Mass spectrometry (MS) is well-known for its sensitivity and selectivity, which is capable of rapid sample identification and quantification. It has been widely used for life science, food safety and environment investigation.The investigations about modern MS analysis have been focused on the development of new ionization sources, the improvement of the new way of sample introduction, the principle and application of the new ionization sources. Among them, the development of new ionization sources is very important. However, when some conventional ionization sources, such as ESI, CI, MALDI are used for complex samples (such as, high-salt sample, biological sample), the sensitivity is poor due to the interferences from complex matrices. Thus a simpler sample pretreatment method prior to MS ionization is still needed. The most widely used sample pretreatment methods are LC, GC, CE. However, when we use these methods to clean up the complex samples, the operation process would be complex and time-consuming. Therefore, it’s still needed to develop new, on-line, no pretreatment ionization sources to analyze complex samples, such as paper spray ionization, DESI, EESI. Among these methods, paper spray ionization owes unique advantages as its low cost and easy operation. Thus, paper spray ionization has been used for quantification of small molecules in dried blood spots (DBS) samples. However, the lack of proper sample preparation would result in poor sensitivity due to the interferences from complex matrices. Meanwhile, benchtop MS instrument is usually not suitable for field applications and at-home diagnosis due to its weight, size and power consumption.To overcome these problems, we combine paper-based device with paper spray ionization. Three-dimensional μPADs recently reported by Whitesides, Crooks mainly carried the advantages of small size, disposability and easy to carry/use. Moreover, Ismagilov has reported a paper-based analytical device (uPAD) based on the slip chip concept, in which the flow of the solution could be easily controlled by slipping one layer relative to the other. Based on these principles, we designe three different paper-based analytical device (μPAD) to overcome the limited use of benchtop MS, the ion suppression effect from complex matrices and the poor selectivity of proteins analysis.Thus our paper is focused on the development of new paper-based analytical device (μPAD) to combine with paper spray ionization. Our paper consisted of three parts. Firstly, to overcome the limited use of benchtop MS, we design a paper-based analytical device (μPAD) which has dual detection zones, one of which is used for rapid screening by colorimetric detection with bare eyes and the other one of which is used for sensitive measurement by PS MS. Secondly, to overcome the ion suppression effect from complex matrices, we design a simple and high efficient paper-based device for matrices removal of DBS samples prior to final paper spray ionization mass spectrometry identification. There are two channels with different functions in our device, one of which is designed for matrices removal and the other one is designed for elution and ionization of analyte. Lastly, to overcome the poor selectivity of proteins analysis, we design a hollow-channel paper analytical device which has two hydrophilic channels, one of which is used for chemiluminescence detection of proteins, and the other one of which is used for mass spectrometer to quantitatively detect protein.In a word, we have designed different kind of paper-based analytical device (μPAD) to realize the analysis of peptides in complex samples, the analysis of different drugs in dried blood spots (DBS) samples and the analyze of proteins. Since the combination of paper-based analytical device (μPAD) with paper spray ionization has the characteristic of high throughput, fast, safety, high selectivity and sensitivity, the use of this method would be widely, such as life science, food safety and environment investigation. |
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