DART®-OS 实时直接分析离子源

石膏墙板也叫石膏板、灰板或干墙(drywall)。最近关于“中国进口的石膏墙板质量纠纷”在美愈演愈烈。美国消费品安全委员会说，已经接到大约 1500个投诉报告，涉及数十亿美元的赔偿投诉。投诉者称，他们所居住新房子上的中国制石膏墙板散发出类似臭鸡蛋味儿的含硫气体，腐蚀电缆铜线和金属管 道，并且时常使人出现头痛、喉咙痛等症状。为此，美国太平洋大学的太平洋质谱实验室受委托应急检测了中美两国生产的石膏板，分析采用DART和精确质量 TOF质谱，TOF分辨率为7000。样品未经萃取或任何化学前处理，直接放置于DART源和质谱接口处。结果显示，在室温下，美国和中国生产的石膏板没 有显著区别，都没有含硫化合物离子存在。当DART快速升温至250℃时，中国产石膏板明显释放出臭味。质谱鉴定，中国石膏板含有的硫化物是美国产品的 46倍。其中含有的组分包括 S2-（63.9440 Da）、 SO2-（63.9615 Da）、 SO3-、S2O-、S3-、 S4-等。

Direct analysis in real time (DART) ion source is a powerful ionising technique for the quick and easy detection of various organic molecules without any sample preparation steps, but the lack of quantitation capacity limits its extensive use in the field of phytochemical analysis. Objective – To improvise a new system which utilize DART-MS as a hyphenated detector for quantitation. Methodology – A total extract of Schisandra chinensis fruit was analyzed on a TLC plate and three major lignan compounds were quantitated by three different methods of UV densitometry, TLC-DART-MS and HPLC-UV to compare the efficiency of each method. To introduce the TLC plate into the DART ion source at a constant velocity, a syringe pump was employed. The DART-MS total ion current chromatogram was recorded for the entire TLC plate. The concentration of each lignan compound was calculated from the calibration curve established with standard compound. Results – Gomisin A, gomisin N and schisandrin were well separated on a silica-coated TLC plate and the specific ion current chromatograms were successfully acquired from the TLC-DART-MS system. The TLC-DART-MS system for the quantitation of natural products showed better linearity and specificity than TLC densitometry, and consumed less time and solvent than conventional HPLC method. Conclusion – A hyphenated system for the quantitation of phytochemicals from crude herbal drugs was successfully established. This system was shown to have a powerful analytical capacity for the prompt and efficient quantitation of natural products from crude drugs.

Piper betle Linn. is a traditional plant associated with the Asian and southeast Asian cultures. Its use is also recorded in folk medicines in these regions. Several of its medicinal properties have recently been proven. Phytochemical analysis showed the presence ofmainly terpenes and phenols in betel leaves. These constituents vary in the different cultivars of Piper betle. In this paper we have attempted to profile eight locally available betel cultivars using the recently developed mass spectral ionization technique of direct analysis in real time (DART). Principal component analysis has also been employed to analyze the DART MS data of these betel cultivars. The results show that the cultivars of Piper betle could be differentiated using DART MS data.

实时直接分析（DART®）与基于orbitrap（静电场轨道阱）技术的（超）高分辨质谱相结合，已在多种霉菌毒素的快速定量分析中得到应用，样品为经改良QuEChERS方法提取的小麦和玉米。 首先评价了几组霉菌毒素用DART技术所获得的离子化效率，然后优化样品提取方法和仪器参数设置，以使大部分强离子化的毒素得到灵敏、准确的测定，这些毒素包括脱氧萎镰菌醇、瓜萎镰菌醇、玉米赤霉烯酮、乙酰脱氧瓜萎镰菌醇、去环氧脱氧瓜萎镰菌醇、镰刀菌烯酮-X、互隔交链孢霉素、交链孢霉酚、交链孢霉甲基醚、蛇形霉素、杂色曲霉素。各分析物的最低校正限（LCL）在50到 150 [mu]g kg-1之间。用基质匹配标准样品或市售13C标记的内标（用于脱氧萎镰菌醇、瓜萎镰菌醇和玉米赤霉烯酮）进行定量分析。采用同位素稀释技术添加500 [mu]g kg-1时获得了良好的回收率（100-108%）和重现性（RSD 5.4-6.9%）。用基质匹配校正，回收率和重现性分别为84-118% 和7.9-12.0% (RSD)。通过分析小麦/玉米有证标准物质（CRM）验证了DART-orbitrapMS所得数据的准确性。所测结果与用超高效液相色谱-飞行时间质谱方法所得文献值完全一致。