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Comprehensive two-dimensional gas chromatography, or GC×GC, is a multidimensional gas chromatography technique that was originally described in 1984 by J. Calvin Giddings [1] and first successfully implemented in 1991 by John Phillips and his student Zaiyou Liu. [2] GC×GC utilizes two different columns with two different stationary phases. In ...
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The USP Controlled Room Temperature is a series of United States Pharmacopeia guidelines for the storage of pharmaceuticals; [1] the relevant omnibus standard is USP 797. [2] [3] Although 100% compliance remains challenging for any given facility, [4] the larger protocol may be regarded as constituting a form of clean room [5] which is included in a suite of best practices.
Gas chromatography (GC) is a common type of chromatography used in analytical chemistry for separating and analyzing compounds that can be vaporized without decomposition. Typical uses of GC include testing the purity of a particular substance, or separating the different components of a mixture. [ 1 ]
The trap is then heated and the sample compounds are introduced to the GC–MS column via a volatiles interface, which is a split inlet system. P&T GC–MS is particularly suited to volatile organic compounds (VOCs) and BTEX compounds (aromatic compounds associated with petroleum). [11] A faster alternative is the "purge-closed loop" system.
In NMR spectroscopy, e.g. of the nuclei 1 H, 13 C and 29 Si, frequencies depend on the magnetic field, which is not the same across all experiments. Therefore, frequencies are reported as relative differences to tetramethylsilane (TMS), an internal standard that George Tiers proposed in 1958 and that the International Union of Pure and Applied Chemistry has since endorsed.
Gas chromatography–vacuum ultraviolet spectroscopy (GC-VUV) is a universal detection technique for gas chromatography. [1] VUV detection provides both qualitative and quantitative spectral information for most gas phase compounds. GC-VUV spectral data is three-dimensional (time, absorbance, wavelength) and specific to chemical structure.
The EPA's Good Laboratory Practice Standards (GLPS) compliance monitoring program guarantees the accuracy and reliability of test data submitted to the Agency to support pesticide product registration under the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA), section 5 of the Toxic Substances Control Act (TSCA), and in accordance ...