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Determinative Techniques to Measure Organics and Inorganics
Published in Paul R. Loconto, Trace Environmental Quantitative Analysis, 2020
In a human, the heart is the most important organ in the body. The reasons for this are found in the field of human physiology. So too, in a GC, the chromatographic column is where separations take place, and the purpose of doing GC is to separate components in a mixture. Historically, packed GC columns dominated gas chromatographic separations up until around 1980. At that time, any work with capillary columns was accomplished using glass. This required that the ends of the coiled and brittle glass columns be heated until softened to enable an installation into the GC to occur. It took a significant level of patience and skill to install a glass capillary GC column at that time. Open tubular columns owe their origins to Marcel Golay and their present robustness from the development of fused-silica capillaries at Hewlett-Packard.30,31
Water: Drinking
Published in Brian D. Fath, Sven E. Jørgensen, Megan Cole, Managing Water Resources and Hydrological Systems, 2020
Marek Biziuk, Matgorzata Michalska
For final determination, GC with specific detectors such as ECD, nitrogen-phosphorus detector (NPD), flame photometric detector, atomic emission detector (AED), and electrolytic conductivity detector (ELCD), or GC with universal detectors such as flame ionization detector (FID) or mass spectrometry (MS) is used. Liquid chromatography methods with ultraviolet (UV), MS, diode-array (DAD), electrochemical, or fluorescent detectors are also often used.[53–58,62,63,65–68,92–96] In Figure 2, two main ways of determining organic compounds in water are shown: determination of individual compounds or of total parameters. Total parameters such as total organic carbon or halogen (TOC, TOX), dissolved organic carbon or halogen (DOC, DOX), and suspended organic carbon or halogen (SOC, SOX) are used to characterize the content of organic compounds in water. Other parameters are defined in terms of the method of isolation of an organic fraction from water: volatile (VOC, VOX) or purgeable (POC, POX), extractable (EOC, EOX), and adsorbable (AOC, AOX) organic carbon or halogen. However, total parameters measuring the carbon content in an organic fraction are not particularly suitable as an estimate of anthropogenic water pollutants and their hazard to human health since a decisive majority of organic compounds in water are biogenic.
Critical Cleaning of Advanced Lubricants from Surfaces
Published in Leslie R. Rudnick, Synthetics, Mineral Oils, and Bio-Based Lubricants, 2020
Ronald L. Shubkin, Barbara F. Kanegsberg, Ed Kanegsberg
One problem is that some US regulations sharply restrict the level of organic compounds that are Volatile Organic Compounds (VOCs). A few organic compounds with low reactivity have been classed as VOC exempt. In many areas, they can be used with few if any environmental restrictions. Relatively few of these, however, are useful in aqueous blends. To further complicate the situation, some regulatory agencies have programs to determine the VOC content by analytical detection rather than by actual content [20]. Gas chromatography/mass spectroscopy (GC/MS) depends on the sample preparation and transfer technique used in the test laboratory. High-boiling organics and complex mixtures may not volatize at the injection temperature of the GC/MS and therefore will not show up in the analysis. To maximize available options, it is necessary to consider all applicable environmental regulations, not just the complete list of components as provided by the manufacturer.
Analytical methods in fatty acid analysis for microbial applications: the recent trends
Published in Preparative Biochemistry & Biotechnology, 2021
Mohammad Homayoonfar, Reza Roosta Azad, Soroush Sardari
There are two types of detectors which regularly used for GC analysis: Flame Ionization Detector (FID) or Mass Spectroscopy (MS). FID is widely used for analysis of fatty acids while providing desired accuracy and sensitivity required for such analysis. Meanwhile emerging technology of mass spectroscopy provides a more sensitive analysis when combined by GC. Therefore, mass spectroscopy refines the separated fractions by GC, according to mass to charge ratios and this can be interpreted as a quantitative measure of the analysis.[4] The ionization of the samples generally is performed by electroionization (EI) or Electron-capture negative ionization (ECNI) setups.[65]Table 4 presented the specific detector used for the analysis of different microbial samples.
Phosphorus in water: A review on the speciation analysis and species specific removal strategies
Published in Critical Reviews in Environmental Science and Technology, 2023
Yuqian Jia, Shuhui Sun, Shu Wang, Xing Yan, Jieshu Qian, Bingcai Pan
GC could be equipped with selective detectors, such as electron capture detector (ECD), flame photometric detector (FPD), and nitrogen and phosphorus detector (NPD), for the analysis of trace OP (Gao et al., 2013; Pantelaki & Voutsa, 2019; Wang et al., 2009). The coupling of GC with MS detector could provide more structural information of OP with greatly improved accuracy of the qualitative analysis. Of note is that it is difficult to use GC to directly analyze OP compounds that are thermally unstable, non-vaporizable, and highly polar, and additional chemical derivatization is always required.