Abstract: An ultrasonic transmitter (95) and detector (e.g., integrated as an ultrasound transducer) utilized in a feedback control system automatically monitors and/or detects surface profile (e.g., shape) of the liquid-air interface and adjusts the flow rate of sampling liquid to ensure that experimental conditions remain consistent at the time of sample introduction during serial samplings. The feedback control can provide for automated adjustment of the surface profile of the liquid-air interface in accordance with changes in desired set point according to an experimental workflow (e.g., automated adjustment between an interface corresponding to a vortex sampling set point and an overflow cleaning set point).

Abstract: A fluid processing system that can include a sample container having a sample chamber for containing a fluid and a plurality of magnetic particles and at least one movable magnetic assembly configured to be movably inserted into or out of the sample chamber. The movable magnetic assembly can include a plurality of electromagnets that generate a magnetic field within at least a portion of the sample chamber when the assembly is inserted at least partially into the sample chamber. The fluid processing system can also include a signal generator that applies electrical signals, e.g., AC electrical signals, to the electromagnets of the magnetic assembly and a controller coupled to the signal generator that is configured to control phases of the electrical signals applied to the electromagnets to generate magnetic field gradients within the portion of the sample chamber effective to magnetically influence the plurality of the magnetic particles.

Abstract: Mass spectrometer based analytical systems and methods in which a feedback control system can be utilized to control the flow of liquid within a sampling probe to adjust and/or maintain the surface profile (e.g., shape) of the liquid-air interface within an open sampling port of the sampling probe. The feedback control systems can automatically monitor and/or detect the surface profile of the liquid-air interface and adjust the flow rate of the sampling liquid to ensure that experimental conditions remain consistent at the time of sample introduction during serial samplings. These can provide stable and reproducible analyte flows of consistent dilution to the ion source, increasing reproducibility and/or accuracy of data generated by MS analysis. Can be used with a change in the desired set point according to the particular experimental workflow (e.g., automated adjustment between an interface corresponding to a sampling set point and a cleaning set point).

Abstract: Methods and systems are provided for reducing the occurrence of unwanted electrical discharge when operating an electrospray ion source to generate ions for mass spectrometric analysis. In accordance with various aspects of the applicant's teachings, the methods and systems described herein can provide for controlling the ion emission current so as to limit the onset of avalanche of electrical discharge between the electrospray electrode and the counter electrode under ionization conditions that typically tend to increase the likelihood of such discharge (arcing), while nonetheless providing for maximal ionization efficiency.

Abstract: Methods and apparatus for processing fluids on a macro- or micro-scale are described. In various aspects, a fluid may have a plurality of elongated (i.e., substantially rod-shaped) magnetic elements disposed therein within a fluid container. An illustrative fluid container is an actuator electrode or a processing vial of a microfluidic device, such as a digital microfluidic device. A magnet component may be configured to generate a magnetic force sufficient to influence the movement of the plurality of elongated magnetic elements within the fluid to be processed. For example, the magnetic force (or magnetic force gradient) may influence the plurality of elongated magnetic elements to rotate, spin, and/or move laterally side-to-side. The shape and movements of the plurality of elongated magnetic elements facilitate the rapid and efficient processing of the fluid, such as fluid mixing and/or fluid separation.

Abstract: Methods and systems for delivering a liquid sample to an ion source for the generation of ions and subsequent analysis by mass spectrometry are provided herein. In accordance with various aspects of the present teachings, MS-based systems and methods are provided in which the flow of desorption solvent within a sampling probe fluidly coupled to an ion source can be selectively controlled such that one or more analyte species can be desorbed from a sample substrate inserted within the sampling probe within a decreased volume of desorption solvent for subsequently delivery to the ion source. In various aspects, sensitivity can be increased due to higher desorption efficiency (e.g., due to increased desorption time) and/or decreased dilution of the desorbed analytes.

Abstract: Methods and apparatus for processing fluids are described. In various aspects, a fluid processing system may include a magnetic assembly that includes a plurality of magnetic structures configured to generate a magnetic field gradient within a fluid container. The magnetic structures may be formed as a plurality of electromagnets configured to be individually actuated by a controller. Each of the electromagnets may generate a magnetic field within the fluid container. The electromagnets may be differentially actuated to create a magnetic field gradient within the fluid container to agitate, mix, or otherwise influence magnetic particles disposed within the fluid container. Activation of the electromagnets of an electromagnetic structure may generate a magnetic field gradient that influences magnetic particles in an x-y direction.

Abstract: Because most ion optics of mass spectrometry systems are subject to ion deposition and may exhibit significantly different behavior following substantial contamination (e.g., loss of sensitivity), fouled surfaces must be regularly cleaned to maintain sensitivity. While the surfaces of front-end components (e.g., curtain plates, orifice plates, Qjet, Q0, IQ0) may be relatively easy to clean, the fouling of components contained within the downstream high-vacuum chambers (e.g., Q1, IQ1) can incur substantial delays and expense as the high-vacuum chambers must be vented and substantially disassembled prior to cleaning. Methods and systems for controlling contamination of components of mass spectrometer systems are provided herein. By reducing the transmission of contaminating ions during non-data acquisition periods, the present teachings can increase throughput, improve robustness, and/or decrease the downtime typically required to vent/disassemble/clean the fouled components.

Abstract: An apparatus includes a first electrode and a second electrode. The second electrode is placed in parallel with the first electrode to provide constant gap distance. The gap between the first electrode and the second electrode is at atmospheric pressure. Ions are introduced into the center of the gap and travel through the apparatus in a direction parallel to the first electrode and the second electrode. The apparatus is configured as a high-field symmetric-waveform apparatus for filtering high mobility ions or for fragmenting ions. The apparatus is also configured for three modes of operation: as a conventional DMS; as a filter high mobility ions; and as fragmentation device. A symmetric electric field is produced in the gap with a maximum density normalized field strength greater than 10 Td to filter high mobility ions and with a maximum density normalized field strength greater than 100 Td to fragment ions.

Abstract: Methods and systems are provided for reducing the occurrence of unwanted electrical discharge when operating an electrospray ion source to generate ions for mass spectrometric analysis. In accordance with various aspects of the applicant's teachings, the methods and systems described herein can provide for controlling the ion emission current so as to limit the onset of avalanche of electrical discharge between the electrospray electrode and the counter electrode under ionization conditions that typically tend to increase the likelihood of such discharge (arcing), while nonetheless providing for maximal ionization efficiency.

Abstract: Methods and apparatus for processing fluids are described. In various aspects, a fluid processing system may include a magnetic assembly that includes a plurality of magnetic structures configured to generate a magnetic field gradient within a fluid container. The magnetic structures may be formed as a plurality of electromagnets configured to be individually actuated by a controller. Each of the electromagnets may generate a magnetic field within the fluid container. The electromagnets may be differentially actuated to create a magnetic field gradient within the fluid container to agitate, mix, or otherwise influence magnetic particles disposed within the fluid container. Activation of the electromagnets of an electromagnetic structure may generate a magnetic field gradient that influences magnetic particles in an x-y direction.

Abstract: Methods and systems for delivering a liquid sample to an ion source for the generation of ions and subsequent analysis by mass spectrometry are provided herein. In accordance with various aspects of the present teachings, MS-based systems and methods are provided in which a desorption solvent utilized in a sampling interface to desorb one or more analyte species from an SPME device is fluidly coupled to an ion source for ionizing the one or more analyte species desorbed into the desorption solvent for subsequent mass spectrometric analysis (e.g., without a liquid chromatography (LC) column between the sampling interface and the ion source).

Abstract: Differential mobility spectrometry is performed under vacuum. Ions generated in a high pressure region are received from the inlet orifice of a vacuum chamber using a first ion guide located in the vacuum chamber. The first ion guide focuses the generated ions on a DMS device inlet end using a plurality of tapered electrodes. The DMS device is coaxial and adjacent to the first ion guide. The DMS device separates the focused ions using a plurality of electrodes. The inscribed diameter at the DMS device inlet end is larger than the inscribed diameter at the first ion guide exit end to maximize ion transfer. The separated ions are received from the DMS device using a second ion guide coaxial and adjacent to the DMS device. The second ion guide focuses the separated ions on an exit orifice of the vacuum chamber using a plurality of tapered electrodes.

Abstract: Systems and methods for delivering a sample to a mass spectrometer are provided. In one aspect, the systems and methods can provide efficient cooling of an ion source probe to prevent overheating and the resulting degradation in ion sampling. In some aspects, such cooling can result in improved consistency and/or efficiency of ion formation. Moreover, ion source cooling in accordance with various aspects of the present teachings can allow for the use of higher temperatures in the ionization chamber (thereby improving desolvation) and/or can enable the use of lower flow rate sample sources than with conventional techniques.

Abstract: A method and system for performing an ion mobility based analysis that ionizes the components of a sample into ions; provides a field asymmetric waveform ion mobility or differential mobility spectrometry ion mobility based filter that comprises at least two electrodes, the at least two electrodes being spaced apart such that a constant sized gap is formed there between, through which a drift gas flows; introducing said ions into the drift gas, wherein said drift gas also comprises a mixture of liquid modifiers.

Abstract: A method and apparatus for performing differential mobility spectrometer (DMS) which includes decreasing the amount of time that ions spend inside fringing fields generated by the DMS. The apparatus includes an entrance electrode plate sealingly engaged to the entrance of the DMS, and is electrically separated from the parallel plate electrodes of the DMS, the entrance electrode plate has an aperture for allowing the traversal of ions into the DMS; wherein the cross-sectional area of the aperture is less than the cross-sectional area of the ion path, the ion path being located between the two parallel plate electrodes of the DMS. The entrance electrode plate may also have a focusing potential applied to it for focusing of ions.

Abstract: A sample analysis system having a continuous beam ion mobility filter incorporates an ion removal mechanism for removing residual ions from the ion mobility filter to reduce cross-talk. A sample to be analyzed by the sample analysis system can be entered into the continuous beam ion mobility filter, which filters the ions of the sample and passes the filtered group of ions to a detector or a mass analyzer (e.g., via an ion optics assembly disposed between the mass analyzer and the ion mobility filter), where some or all of the ions in the group are detected. The ion removal mechanism then removes all or a substantial portion of the residual ions from the ion mobility filter that are left over from the first filtered group before a second filtered group is passed through. In some aspects, the ion removal mechanism can be operated concurrent with an ion removal mechanism for removing residual ions from an ion optics assembly.

Abstract: Methods and systems for delivering a liquid sample to an ion source for the generation of ions and subsequent analysis by mass spectrometry are provided herein. In accordance with various aspects of the present teachings, MS-based systems and methods are provided in which a desorption solvent utilized in a sampling interface to desorb one or more analyte species from an SPME device is fluidly coupled to an ion source for ionizing the one or more analyte species desorbed into the desorption solvent for subsequent mass spectrometric analysis (e.g., without a liquid chromatography (LC) column between the sampling interface and the ion source).

Abstract: Methods and systems for performing mass spectrometry are provided herein. In accordance with various aspects of the applicants' teachings, the methods and systems can utilize an ion mobility spectrometer operating at atmospheric or low-vacuum pressure to remove the major contributors to the contamination and degradation of critical downstream components of a mass spectrometer located within a high-vacuum system (e.g., ion optics, mass filters, detectors), with limited signal loss.

Abstract: A method and system for performing an ion mobility based analysis that ionizes the components of a sample into ions; provides a field asymmetric waveform ion mobility or differential mobility spectrometry ion mobility based filter that comprises at least two electrodes, the at least two electrodes being spaced apart such that a constant sized gap is formed there between, through which a drift gas flows; introducing said ions into the drift gas, wherein said drift gas also comprises a mixture of liquid modifiers.