A system for sampling a liquid includes a sample fluid conduit including a membrane having pores. The membrane prevents the passage of the sample liquid through the pores at a first pressure of the sample liquid in the sample fluid conduit. A surface sampling capture probe has a distal end. The capture probe includes a solvent supply conduit and a solvent exhaust conduit. A solvent composition flowing at the distal end of the capture probe establishes a liquid junction with the membrane and establishes a second pressure within the liquid junction at the membrane. The second pressure is lower than the first pressure. Sample liquid will be drawn through the pores of the membrane by the second pressure at the liquid junction. A method for sampling a liquid and for performing chemical analysis on a liquid are also disclosed.

The present invention relates to a process for the preparation of angiotensin receptor blockers or its pharmaceutically acceptable salts thereof containing less than 10 ppm of the azido impurities. More particularly, the present invention relates to process for the preparation of Losartan, Losartan potassium of Formula I or its other pharmaceutically acceptable salts thereof containing less than 10 ppm of each of the azido impurities, wherein the azido impurity is selected from the group comprising of 5-(4′-(azidomethyl)-[1,1′-biphenyl]-2-yl)-1H-tetrazole, 4′-(azidomethyl)-[1,1′-biphenyl]-2-carbonitrile, 4′-((5-(azidomethyl)-2-butyl-4-chloro-1H-imidazol-1-yl)methyl)-[1,1′-biphenyl]-2-carbonitrile, 5-(4′-((5-(azidomethyl)-2-butyl-4-chloro-1H-imidazol-1-yl)methyl)-[1,1′-biphenyl]-2-yl)-1H-tetrazole, 5-(azidomethyl)-2-butyl-4-chloro-1H-imidazole, 4′-((4-(azidomethyl)-2-butyl-5-chloro-1H-imidazol-1-yl)methyl)-[1,1′-biphenyl]-2-carbonitrile, 5-(4′-((4-(azidomethyl)-2-butyl-5-chloro-1H-imidazol-1-yl)methyl)-[1,1′-biphenyl]-2-yl)-1H-tetrazole and 1-((1-((2′-(1H-tetrazol-5-yl)-[1,1′-biphenyl]-4-yl)methyl)-2-butyl-4-chloro-1H-imidazol-5-yl)methyl)-5-(4′-((5-(azidomethyl)-2-butyl-4-chloro-1H-imidazol-1-yl)methyl)-[1,1′-biphenyl]-2-yl)-1H-tetrazole. More particularly, the present invention relates to a simple, economical and industrially efficient process for the preparation of Losartan potassium of Formula I. The present invention also relates to solid oral pharmaceutical compositions and process for preparing solid oral pharmaceutical compositions comprising losartan or its pharmaceutically acceptable salts thereof and method of detecting azido impurities in these solid oral pharmaceutical compositions.

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Techniques for real-time or substantially real-time peak detection are described. In one embodiment, for example, logic coupled to memory may be configured to receive data from at least one analytical instrument and perform processing or analysis on the received data. Moreover, the logic may be configured to determine, via one or more GPUs or CPUs (or both), one or more peaks based on the processing or the analysis of the received data and generate peak detection data based on the detected one or more peaks in real-time or substantially real-time. Other embodiments are described.

Compositions and methods for analyzing disulfide bonds are provided. An exemplary method includes preparing peptide standards having no disulfide bonds, scrambled disulfide bond peptide standards, and native disulfide bond peptide standards according to the sequence of the region of the protein drug product that includes the disulfide bond, digesting a sample of protein drug product into peptides, separating the protein drug product peptides, analyzing the protein drug product peptides and the peptide standards, identifying scrambled and native disulfide bond peptides by retention time, and quantifying the level of scrambled disulfide bond peptides.

Provided are methods of detecting the presence or amount of a vitamin D metabolite in a sample using mass spectrometry. The methods generally directed to ionizing a vitamin D metabolite in a sample and detecting the amount of the ion to determine the presence or amount of the vitamin D metabolite in the sample. Also provided are methods to detect the presence or amount of two or more vitamin D metabolites in a single assay.

A method of performing mass spectrometry includes accumulating, over an accumulation time, ions produced from components eluting from a chromatography column and transferring the accumulated ions to a mass analyzer. During an acquisition, a mass spectrum of detected ions derived from the transferred ions is acquired. An elution profile is obtained from a series of acquired mass spectra including the acquired mass spectrum and a plurality of previously-acquired mass spectra. The elution profile includes a plurality of detection points representing intensity of the detected ions as a function of time. A current signal state of the elution profile is classified based on a subset of detection points included in the plurality of detection points. The accumulation time for a next acquisition of a mass spectrum is set based on the classified current signal state of the elution profile.

The invention discussed in this application relates to vitamin B12-based compounds that are useful as quantitative standards, particularly for the assessment of vitamin B12 deficiency.

Systems and methods are provided for microbial identification using cleavable tags. Control information is sent to a mass spectrometer to fragment one or more nucleic acid primers labeled with a first tag and monitor for an intensity of the first tag in a mass spectrometry (MS) method. An ion source provides a beam of ions from a polymerase chain reaction amplified sample that includes one or more nucleic acid primers labeled with the first tag. The first tag binds to one or more nucleic acid primers of a known microbe and is cleaved from the nucleic acid primers during the MS method. The mass spectrometer receives the beam of ions and is adapted to perform the MS method on the beam of ions. If the intensity of the first tag received from the mass spectrometer exceeds a threshold value, the known microbe is identified in the sample.

A method for identifying and/or verifying at least one analyte peak in a chromatogram of a sample for said analyte from a liquid chromatography mass spectrometer device, said method comprising: a) determining a chromatogram of the sample by acquiring a plurality of data points for quantifier signal intensities and/or qualifier signal intensities, over time; and, in case the sample comprises an internal standard, optionally acquiring a plurality of data points for internal standard quantifier signal intensities and/or internal standard qualifier signal intensities, over time; b) determining for at least a fraction of the data points acquired in step a), a ratio type; c) comparing the ratios determined in step b) to a reference; and d) identifying and/or verifying at least one analyte peak in a chromatogram based on comparison step c).

The present disclosure relates to a method for determining a carry over of an analyte from a previous sample into a sample of interest on a liquid chromatography mass spectrometer (LC-MS) device, the method comprising the following steps: (a) determining at least one chromatogram of said sample of interest on said LC-MS device; (b) determining a background height of the chromatogram; and (c) determining the carry over of the analyte from said previous sample into the sample of interest based on the background height. The present disclosure also relates to methods, systems, and computer program products related to the aforesaid method.