Methods and systems that can use a gas comprising a nitrogen center that is introduced upstream of a plasma sustained in a torch are described. In some configurations, the gas comprising the nitrogen center can be introduced as a gas upstream of the plasma and through a sample introduction device. Mass spectrometers and optical emission systems that can use the gas comprising the nitrogen center are also described.

Methods and systems that can use a gas comprising a nitrogen center that is introduced upstream of a plasma sustained in a torch are described. In some configurations, the gas comprising the nitrogen center can be introduced as a gas upstream of the plasma and through a sample introduction device. Mass spectrometers and optical emission systems that can use the gas comprising the nitrogen center are also described.

The invention generally relates to enclosed desorption electrospray ionization probes, systems, and methods. In certain embodiments, the invention provides a source of DESI-active spray, in which a distal portion of the source is enclosed within a transfer member such that the DESI-active spray is produced within the transfer member.

The invention generally relates to enclosed desorption electrospray ionization probes, systems, and methods. In certain embodiments, the invention provides a source of DESI-active spray, in which a distal portion of the source is enclosed within a transfer member such that the DESI-active spray is produced within the transfer member.

Systems and methods are provided for determining the organic silicon content of petroleum fractions, such as refinery fractions. This can be achieved in part based on performing solvent-enhanced selective filtration on a hydrocarbonaceous sample to substantially remove inorganic silicon from the sample while retaining at least a substantial portion of the organic silicon in the sample. After the solvent-enhanced selective filtration, the organic silicon content of the filtered sample can be determined. The ability to determine the organic silicon content of a sample can be used to identify crude fractions and/or refinery fractions that may cause contamination problems within a refinery while reducing or minimizing the occurrence of false positive tests that could result from detection of inorganic silicon.

Systems and methods are provided for determining the organic silicon content of petroleum fractions, such as refinery fractions. This can be achieved in part based on performing solvent-enhanced selective filtration on a hydrocarbonaceous sample to substantially remove inorganic silicon from the sample while retaining at least a substantial portion of the organic silicon in the sample. After the solvent-enhanced selective filtration, the organic silicon content of the filtered sample can be determined. The ability to determine the organic silicon content of a sample can be used to identify crude fractions and/or refinery fractions that may cause contamination problems within a refinery while reducing or minimizing the occurrence of false positive tests that could result from detection of inorganic silicon.

A plurality of product ion spectra measured over plurality of cycles for each precursor ion mass selection window of two or more precursor ion mass selection windows are received from a tandem mass spectrometer. A product ion extracted ion chroatograms (XIC) is calculated for each precursor ion mass selection window of the two or more precursor ion mass selection windows from the plurality of product ion spectra for each precursor ion mass selection window. Two or more product ion XICs are produced. A two-dimensional binary bit matrix is generated to represent each product ion XIC of the two or more product ion XICs. For each XIC of the two or more product ion XICs, the binary bit matrix is separately initialized with binary values calculated from each XIC and the initialized binary bit matrix is compared with stored information about known compounds to identify known compounds of each XIC.

A plurality of product ion spectra measured over plurality of cycles for each precursor ion mass selection window of two or more precursor ion mass selection windows are received from a tandem mass spectrometer. A product ion extracted ion chroatograms (XIC) is calculated for each precursor ion mass selection window of the two or more precursor ion mass selection windows from the plurality of product ion spectra for each precursor ion mass selection window. Two or more product ion XICs are produced. A two-dimensional binary bit matrix is generated to represent each product ion XIC of the two or more product ion XICs. For each XIC of the two or more product ion XICs, the binary bit matrix is separately initialized with binary values calculated from each XIC and the initialized binary bit matrix is compared with stored information about known compounds to identify known compounds of each XIC.

Disclosed is an apparatus for and a method of mass analysis, the apparatus and the method being capable of improving a detection accuracy of a target substance including impurities, without increasing a size of the apparatus, and shortening measuring time. The apparatus analyzing a sample containing a target substance and one or more interfering substances, which have a peak of a mass spectrum overlapping that of the target substance includes: a peak correction unit calculating an intensity of net peak D of the mass spectrum of the target substance by subtracting a total sum of estimated intensities of the peak B, which are calculated every predetermined time interval according to the intensity of the peak A and a nonlinear relation F between the peak A and the peak B, from an intensity of peak C of a mass spectrum of the target substance of the sample.

Disclosed is an apparatus for and a method of mass analysis, the apparatus and the method being capable of improving a detection accuracy of a target substance including impurities, without increasing a size of the apparatus, and shortening measuring time. The apparatus analyzing a sample containing a target substance and one or more interfering substances, which have a peak of a mass spectrum overlapping that of the target substance includes: a peak correction unit calculating an intensity of net peak D of the mass spectrum of the target substance by subtracting a total sum of estimated intensities of the peak B, which are calculated every predetermined time interval according to the intensity of the peak A and a nonlinear relation F between the peak A and the peak B, from an intensity of peak C of a mass spectrum of the target substance of the sample.