Provided herein is a method and system for PFAS analysis using a liquid chromatography technique that employ a first column (e.g., an isolator column) and a second column (e.g., an analytical column), wherein at least one of the first column, the second column, or both the first and second columns include mixed mode with anion exchange surface chemistry. The devices and methods provided herein are useful for improving the efficiency and/or sensitivity of systems implementing liquid chromatography for PFAS analysis. The methods of the present disclosure are particularly beneficial for trace level (e.g., ppm level or lower) analysis of PFAS. Further, the methods of the present disclosure allow improved separation of short-chain and ultrashort-chain PFAS.

The present invention relates to method and an apparatus for quantitatively analyzing a gaseous process stream, in particular a stream from a process for producing ethylene carbonate and/or ethylene glycol, in particular where such stream comprises gaseous organic iodides.

The present invention provides a novel method that is capable of detecting a trifluridine-related substance from a sample containing trifluridine or a salt thereof by high-performance liquid chromatography comprising two steps that are performed under gradient conditions. More specifically, the method is for detecting a trifluridine-related substance, the method comprising the step of subjecting a sample containing trifluridine or a salt thereof to high-performance liquid chromatography using a mobile phase composed of an organic phase and an aqueous phase, wherein the step of high-performance liquid chromatography comprises steps 1 and 2 that satisfy the following requirements: Step 1: the percentage of the organic phase in the entire mobile phase is 1 to 14% by volume; and Step 2: after step 1, elution is performed by applying a gradient of increasing the percentage of the organic phase in the entire mobile phase.

In a quantitative determination device 10 for brominated flame-retardant compounds, a storage section 41 holds a relative response factor 411 representing a relationship of a measured intensity of a compared compound to that of a reference compound selected from target compounds. A standard-sample measurer 43 acquires the intensity of the reference compound by measuring a standard sample, using an analyzer 10, 20. A target-sample measurer 45 acquires the intensities of the reference and compared compounds by measuring a target sample, using the analyzer. A reference-compound quantity determiner 46 determines a quantitative value of the reference compound in the target sample. A compared-compound quantity determiner 47 determines a quantitative value of the compared compound based on the quantity of the reference compound in the standard sample, intensity of the reference compound acquired by the standard-sample measurer, intensity of the compared compound acquired by the target-sample measurer, and relative response factor of the compared compound.

In a quantitative determination device 100 for brominated flame-retardant compounds, a storage section 41 holds a relative response factor 411 representing a relationship of a measured intensity of a compared compound to that of a reference compound selected from target compounds. A standard-sample measurer 43 acquires the intensity of the reference compound by measuring a standard sample, using an analyzer 10, 20. A target-sample measurer 45 acquires the intensities of the reference and compared compounds by measuring a target sample, using the analyzer. A reference-compound quantity determiner 46 determines a quantitative value of the reference compound in the target sample. A compared-compound quantity determiner 47 determines a quantitative value of the compared compound based on the quantity of the reference compound in the standard sample, intensity of the reference compound acquired by the standard-sample measurer, intensity of the compared compound acquired by the target-sample measurer, and relative response factor of the compared compound.

The present invention concerns a HPLC separation method useful in the synthesis of [.sup.18F]-labelled compounds, including positron emission tomography (PET) tracers. The method of the invention addresses constraints of previous methods imposed by the needs of free 5 [18F]fluoride. The present invention provides a simplified process that enables rapid separation and analysis of free [.sup.18F]fluoride and chemical impurities in the synthesis of [.sup.18F]-labelled compounds.

An ion beam analysis method to quantitatively measure the presence of fluorinated compounds in aqueous samples. The method is a quick, cost effective, nondestructive and quantitative, screen for the presence of fluorinated compounds in solution. The present invention includes a novel method of using an ion beam analysis method (such as PIGE) in air (ex vacuo) to unambiguously easily, quickly, accurately, precisely and cost effectively identify the presence of fluorinated compounds (such as PFASs) that have been extracted from aqueous solutions. The present invention may be used with a wide variety of aqueous solutions, including environmental groundwater samples, with little processing.

A real-time method and analytical system for determining haloacetic acids in water which operate by: (1) extracting samples on ion-exchange absorbent medium; (2) concentrating haloacetic acids on hyper-crosslinked medium; (3) eluting the analytes from the concentration medium for injection into an HPLC system; (4) separating individual haloacetic acid in reverse-phase chromatography performed by the HPLC system; and (5) measuring optical characteristics (UV-absorbance) of haloacetic acids, to determine concentration. The entire process can be performed using a completely self-contained, in-situ mechanism that sits at a water distribution point for 24/7 testing, with automated control, monitoring, reporting, and employment of remedial measures (e.g., automated adjustment of the water treatment process).

A primary trap concentrates the sample, followed by forward flushing of retained compounds more volatile than CO.sub.2 to a secondary trap. In some embodiments, prior to CO.sub.2 elution, the primary trap is isolated from the secondary trap and pressure in the primary trap is reduced to sub-atmospheric. At this time, a pressure sensor measures expansion of CO.sub.2 into a vacuum reservoir to determine the amount of CO.sub.2 and CO.sub.2 is removed. Optionally, inert gas is used to eliminate any remaining CO.sub.2, either at positive pressure instead of removing CO.sub.2 under vacuum, or as an optional additional step after removing CO.sub.2 under vacuum. After the CO.sub.2 is removed, the primary trap is heated and backflushed to the secondary trap, which is then preheated and either injected directly to a GCMS, or further condensed using an open tubular focusing trap for even faster injection rates into the GCMS.

The present disclosure provides a method for measuring a concentration of a per- and polyfluoroalkyl substance and a liquid chromatography-tandem mass spectrometry system. The method includes: measuring concentrations of a plurality of per-and polyfluoroalkyl substances in a sample by liquid chromatography-tandem mass spectrometry in a primary measurement process of eluting the sample with an alkaline mobile phase, in which the plurality of per- and polyfluoroalkyl substances at least include one or more perfluoroalkyl phosphonic acids/phosphinic acids or polyfluoroalkyl phosphate esters. According to the method, by using the alkaline mobile phase to elute the sample, the rapid analysis on 93 PFASs including perfluoroalkyl phosphonic acids/phosphinic acids and polyfluoroalkyl phosphate esters can be completed by single injection. Additionally, the present disclosure also provides a method to rapidly analyze 10 PFASs by GC-MS/MS.