Current-Controlled Nanospray Ionization Mass Spectrometry
Current-Controlled Nanospray Ionization Mass Spectrometry
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DOI：
10.1016/j.jasms.2009.03.007
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发表时间：
2009-07-01
影响因子：
3.2
通讯作者：
Fabris, Daniele
中科院分区：
文献类型：
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作者：
Gapeev, Alexei;Berton, Alberto;Fabris, Daniele
通过构建能够读取电流并实时重新调整发射器电压的反馈装置，测试了直接测定电喷雾电流将提供一种维持喷雾稳定性以实现最佳纳喷雾分析的可行方法的假设。该装置由一个电流传感电路组成，该电路读取位于高压电源和纳喷雾发射器之间的电阻器上的压降。生成与观察到的电流成比例的低电压并将其发送到数据采集卡。比例微分积分 (PID) 算法使用该信息来计算用于控制电源输出的低压信号的幅度。因此，传感电阻器上的电流的任何变化都会被施加到纳喷雾发射器的高电压的相反方向的变化所抵消。以这种方式，该设备调节发射器电压以实现电流的预设值，尽管影响喷射状态的参数有任何可能的变化，但该设备努力随时间保持该电流的预设值。初步结果表明，反馈装置能够为传统电压控制分析中通常被认为具有挑战性的样品建立和维持稳定的喷雾，例如由高盐负载核酸溶液组成的样品。对于这些类型的样品，电流控制模式下记录的总离子计数明显比电压控制模式下观察到的更稳定。同时，整体信号强度和信噪比也显着提高。将目标纳喷雾电流设置为预定义值并让设备在无需操作员干预的情况下到达目标，从而能够从含有高达 2.5 M 醋酸铵的溶液中采集可行的数据，而这通常很难通过传统的手动调节来实现。对成分非常不同的样品的电流-电压关系的更深入了解预计不仅能够预测用于某种分析的目标电流，而且能够设计算法以根据样品特性和分析条件的可预测变化来改变此类目标。这将允许在在线梯度色谱期间保持最佳性能，其中喷雾溶液的性质在分析过程中可能变化很大。 (J Am Soc Mass Spectrom 2009, 20, 1334-1341) (C) 2009 由 Elsevier Inc. 代表美国质谱学会出版
The hypothesis that direct determination of electrospray current would provide a viable method for maintaining spray stability to enable optimal nanospray analysis was tested by building a feedback apparatus capable of reading the current and readjusting the emitter voltage in real time. The apparatus consists of a current-sensing circuit that reads the voltage drop across a resistor located between the high-voltage power supply and the nanospray emitter. A low voltage proportional to the observed current is generated and sent to a data acquisition card. The information is used by a proportional-derivative-integral (PID) algorithm to calculate the magnitude of a low-voltage signal that is used to control the power supply output. Any variation of current across the sensing resistor is thus counteracted by an opposite-direction variation of the high voltage applied to the nanospray emitter. In this way, the apparatus adjusts the emitter voltage to achieve a preset value of current, which it strives to maintain over time in spite of any possible variation of the parameters influencing the spray regime. Preliminary results have shown that the feedback apparatus is capable of establishing and maintaining stable spray for samples that are usually considered challenging in traditional voltage-controlled analysis, such as those consisting of nucleic acid solutions with high salt loads. For these types of samples, the total ion count recorded in current-controlled mode was significantly more stable than that observed in voltage-controlled mode. At the same time, overall signal intensities and signal-to-noise ratios were also significantly improved. Setting the target nanospray current to a predefined value and letting the apparatus reach the target without operator intervention enabled the acquisition of viable data from solutions containing up to 2.5 M ammonium acetate, which are ordinarily difficult by traditional manual tuning. A deeper understanding of the current-voltage relationships for samples of very different compositions is expected to enable one not only to predict the target current that should be used for a certain analysis, but also to devise algorithms to change such target as a function of predictable variations of sample properties and analytical conditions. This will allow for optimal performance to be maintained during on-line gradient chromatography in which the nature of the sprayed solution may vary very widely during the course of the analysis. (J Am Soc Mass Spectrom 2009, 20, 1334-1341) (C) 2009 Published by Elsevier Inc. on behalf of American Society for Mass Spectrometry