Methods, devices, and systems for performing nebulization of a sample from a fluid channel of a microfluidic device are described. The systems or devices disclosed herein may comprise microfluidic devices that comprise a gas channel used for nebulization of the sample at a fluid outlet of the microfluidic device. In some instances, the disclosed devices may be designed to perform isoelectric focusing followed by further characterization of the separated analytes using electrospray ionization coupled with nebulization to introduce the samples into a mass spectrometer. The disclosed methods, devices, and systems provide for fast, accurate separation and characterization of protein analyte mixtures or other biological molecules by isoelectric point.

An apparatus for chemical separations includes a first substantially rigid microfluidic substrate defining a first fluidic port; a second substantially rigid microfluidic substrate defining a second fluidic port; and a coupler disposed between the first and second substrates, the coupler defining a fluidic path in fluidic alignment with the ports of the first and second substrates. The coupler includes a material that is deformable relative to a material of the first substrate and a material of the second substrate. The substrates are clamped together to compress the coupler between the substrates and form a fluid-tight seal.

An apparatus for connecting an ionisation probe assembly to a mass and/or ion mobility spectrometer is disclosed. The apparatus comprises: an attachment member for releasably attaching a probe assembly to the apparatus; a cap for enclosing the attachment member; wherein the apparatus is operable to deliver a voltage to a probe assembly only when the cap is arranged to enclose the attachment member; and wherein the cap is configurable to enclose the attachment member when a probe assembly is attached to the apparatus.

A liquid chromatograph mass spectrometer specifying a location where a flow path is clogged and recovering in a short time. The liquid chromatograph mass spectrometer includes a first flow path passing through a separation column, a second flow path not passing through the separation column, a mass spectrometry unit on the downstream side of the first and second flow paths and analyzes a sample that has passed through the first flow path, a first valve for connecting any one of the first and second flow paths to the mass spectrometry unit, and a controller for controlling driving of the first valve, connecting the first flow path to the mass spectrometric unit, comparing the measured value of the mass spectrometric unit with a predetermined threshold value, and connecting the second flow path to the mass spectrometry unit when it is determined to be abnormal.

Disclosed herein is a system for desorbing and detecting an analyte sorbed on a solid phase microextraction (SPME) device. The system includes a desorption chamber sized to accept the SPME device while defining a void volume of less than about 50 μL; a flow injector in fluid connection with the desorption chamber, the desorption chamber and the flow injector being fluidly connected by at least a flow-insulating fluid connector; a solvent source in fluid connection with the flow injector; and a fluid switch that: in a desorption position, allows the solvent to be sprayed from the flow injector while flow-insulating any desorption solution in the desorption chamber, and in an detecting position, turns off the solvent source while maintaining the fluid connection between the flow injector and the desorption chamber, transferring the desorption solution through the flow-insulating fluid connector to the flow injector as a substantially undiluted plug of liquid.

Provided are methods for determining the amount of lacosamide in a sample using mass spectrometry. The methods generally involve ionizing lacosamide in a sample and detecting and quantifying the amount of the ion to determine the amount of lacosamide in the sample.

The invention generally relates to methods of analyzing crude oil. In certain embodiments, methods of the invention involve obtaining a crude oil sample, and subjecting the crude oil sample to mass spectrometry analysis. In certain embodiments, the method is performed without any sample pre-purification steps.

The degree of ion dissociation which occurs within a first intermediate vacuum chamber (212) maintained at a comparatively low degree of vacuum depends not only on the amount of energy of the ion but also on the size and other properties of the ion. Accordingly, a predetermined optimum level of DC bias voltage is applied to an ion guide (24) so as to create, within the first intermediate vacuum chamber (212), a DC electric field which barely induces the dissociation of an ion originating from a target compound in a sample while promoting the dissociation of an ion originating from a foreign substance which will form a noise signal in the observation of the target compound. The optimum DC bias voltage is previously determined by creating extracted ion chromatograms based on data collected under various DC bias voltages and evaluating the SN ratio using the chromatograms. Consequently, the accuracy and sensitivity of the quantitative determination is improved as compared to a conventional system in which only the signal strength of the target compound is considered.

The present invention relates to the technical field of chemical analysis and quantitative detection, in particular to a quantitative detection method for snake venom thrombin-like enzyme (SVTLE) from Agkistrodon halys pallas. The quantitative detection method for the SVTLE includes the following steps of taking a reference substance of marker peptide for the SVTLE from Agkistrodon halys pallas with an amino acid sequence of LDSPVSNSAHIAPLSLPSSAPSVGSVCR, and preparing a series of reference solutions with different concentrations; adding the reference solutions in test solutions respectively for enzymolysis, and then taking a supernatant after enzymolysis as a series of solutions to be detected; and adding the solutions to be detected in a liquid chromatogram-mass spectrometer, and then selecting a qualitative ion pair and a quantitative ion pair to detect contents of marker peptide in the solutions to be detected.

An automated method of monitoring a state of an analyzer is provided including a mass spectrometer (MS) with an electrospray ionization (ESI) source coupled to a liquid chromatography (LC) stream, including monitoring an electrospray ionization current of the ESI source and identifying a condition of multiple conditions of the analyzer based on the monitored ionization current of the ESI source, one of the conditions being a presence of a dead volume in a liquid chromatography stream of the analyzer downstream of an LC column of the LC stream.