Eluents tartaric acid/pyridine-2,6-dicarboxylic

Among many ligands used for simultaneous ion chromatography of metals, the most common eluents used are oxalic acid, tartaric acid, citric acid, 4-(2-pirydylazo)resorcinol (PAR), pyridine-2,6-dicarboxylic acid (PDCA), a-hydroxyi-sobutyric acid (HIBA), 1,2-diaminocyclohexanetetraacetic acid (DCTA), diethylenetriarninepentaacetic acid (DTPA), and ethylenediaminetetraacetic acid (EDTA). 

Cation exchangers based on PBDMA-coated silica are offered by a number of companies. Metrohm (Herisau, Switzerland), for example, offers two columns under the trade names Metrosep Cl and C4. The 5 pm Metrosep Cl is considered to be the high-performance column for the simultaneous analysis of mono-and divalent cations with an analysis time of less than 20 min. It can also be used for the separation of various amines, which are typically eluted with a nitric acid eluent. Figure 4.41 shows an example chromatogram obtained under standard chromatographic conditions with an eluent mixture of tartaric acid and pyridine-2,6-dicarboxyiic acid (PDCA) (dipicohnic acid). Under these chromatographic conditions, calcium elutes ahead of magnesium, followed by strontium and barium. This unusual retention behavior can be attributed to the complex-ing properties of pyridine-2,6-dicarboxylic acid. With a pure tartaric acid eluent. 

Figure 10.9 Cation analysis of a rain water sample. Separator column Metrosep Cation 1 -2 eluent 4 mmol/L tartaric acid +1 mmol/L pyridine-2,6-dicarboxylic acid flow rate 1 ml/ min detection nonsuppressed conductivity ...

Figure 10.224 Determination of alkali and 10 1 detection nonsuppressed conductivity alkaline-earth metals in a red wine. Separator sample Italian red wine diluted 1 50 with column Metrosep Cation 1-2 eluent 4mmol/L deionized water peaks 95mg/L sodium (1), tartaric acid -l-1 mmol/L pyridine-2.6-dicarboxylic 822mg/L potassium (2), 306mg/L caldum (3), acid flow rate 1 mL/min injection volume and 722 mg/L magnesium (see [333]).

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