High-Performance Liquid Chromatography
Joseph Chamberlain in The Analysis of Drugs in Biological Fluids, 2018
Another classical method for effecting extraction of charged compounds from aqueous phases is the technique of ion-pairing, which is also used in altering partition coefficients in HPLC. In the classical method, a counter-ion is added to the solution containing the ion to be extracted and association with a reduced charge is formed; this entity is then extractable with an organic solvent. Thus, for organic acids, a suitable counter-ion would be tetramethylammonium, while for organic bases, such ions as heptane sulfonate have been used. Much of the development of the use of paired ion chromatography is due to the work of Schill681 and Tomlinson et al.682 who have written several extensive reviews on the theory and practice of the technique.
Using iodine for analysis
Tatsuo Kaiho in Iodine Made Simple, 2017
Ion chromatography is a type of liquid chromatography which can qualify and quantify anions such as chloride ions, fluoride ions, and sulfate ions and cations such as sodium ions and ammonia ions with high sensitivity. Ion chromatography uses ion-exchange resin as the stationary phase. By utilizing the difference in the time each substance remains on the ion-exchange resin according to the strength of the charge, substances within a sample can be separated. In the suppressor between the column and the detector, ions which were originally included in the mobile phase are removed and placed on the detector.
Trueness assessment of routine electrolytes measuring systems using the candidate reference method by ion chromatography
Published in Scandinavian Journal of Clinical and Laboratory Investigation, 2021
Rui Zhang, Shunli Zhang, Qingtao Wang
Serum samples contain a large number of organic compounds. The direct injection of macromolecular organic compounds can contaminate the separation column, and the organic substances and heavy metals may cause inhibitor damage. Therefore, sample pretreatment is of vital importance in ion chromatography. Previously, Thienpont et al. have conducted several studies assessing different pretreatment strategies for serum samples [8–10]. They suggested that the dilution factor of the samples should be higher than 20. Otherwise, the divalent ions of calcium and magnesium will remain attached to the proteins. In 2004, Röhker et al. proposed microwave digestion as a pretreatment strategy that can directly mineralize serum samples into inorganic salts [15]. In our study, the samples were pretreated with microwave digestion, and the dilution factor was 25. Calcium and magnesium were released completely, and the accuracy of detection was good. However, the inhibitor of ion chromatography can absorb calcium, which can result in errors. Therefore, the column and inhibitor must be washed with 1% diluted nitric acid frequently.
Identification of the metabolites produced following Iris tectorum Maxim oral administration and a network pharmacology-based analysis of their potential pharmacological properties
Published in Xenobiotica, 2021
Metabolite identification is an essential facet of pharmacological studies, and relies on full-scan product ion spectra for each metabolite. Post-acquisition data mining can then be conducted using extracted ion chromatography (EIC) and neutral loss chromatography. Molecular formulas can additionally be confirmed based on a mass weight accuracy of <5 ppm. Herein, we screened for and identified 51 metabolites associated with the oral administration of I. tectorum Maxim in rats via HPLC − Q-TOF-MS, including 19, 24, and 33 metabolites detected in faeces, urine, and bile samples, respectively. Retention times, proposed molecular formulas, accurate molecular weights, and two-stage mass fragments corresponding to these putative metabolites are presented in Table S2 and Table S3.
Determination and seasonal analysis of physicochemical characterization and metal(oid)s of landfill leachate in Bushehr port along the Persian Gulf
Published in Toxin Reviews, 2023
Azam Mohammadi, Mohammad Malakootian, Sina Dobaradaran, Majid Hashemi, Neemat Jaafarzadeh, Nasrin Parniani
Every leachate sample was analyzed for the physicochemical parameters including pH, alkalinity, EC, TDS, BOD5, COD, TKN, and cation as well as anion concentrations. The pH and EC were measured by using a pH meter (Elico-digital pH meter). The alkalinity, TDS, BOD5, COD, and TKN were determined according to the standard method (APHA AWWA 1998). The concentrations of anions (F−, Cl−, and PO43−) and cations (K+, Na+, Ca2+, and Mg2+) were determined through ion chromatography (Dionex, Sunnyvale, CA, USA). The instrumental conditions of ion chromatography (IC) for the measurement of anions and cations concentrations are displayed in Table S1.
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