Aminopolyphosphonic acid

Fig. 3-97 shows the separation of some aminopolyphosphonic acids of the DEQUEST type that can be eluted with nitric acid at the concentration c = 0.03 mol/ L. Also the analogous compound to EDTP, hexamethylenediamine-tetramethylenephos-phonic acid (DEQUEST 2051)... 

Fig. 3-98. Separation of aminopolyphosphonic acids of the DEQUEST type at a 5-pm anion exchanger. — Separator column IonPac AS6A eluent 0.025 mol/L HN03 flow rate 0.5 mL/min detection see Fig. 3-97 injection volume 50 pL solute concentrations see Fig. 3-97.

A typical compound of the first class is 1-hydroxyethane-1,1-diphosphonic acid (HEDP, DEQUEST 2010), which is often employed in practical applications. As shown in Fig. 3-97, this compound may be analyzed in the same run with other aminopolyphosphonic acids. 

The lonPac AS7 separator column was developed specifically for the analysis of polyvalent anions (Figure 3.56). In the past, polyvalent anions such as amino-polycarboxylic and aminopolyphosphonic acids could not be analyzed by ion chromatography, because their retention times increase drastically with increas-... 

Figure 3.56 Separation of aminopolyphosphonic acids of the DEQUEST type. Separator column lonPac AS7 eluent 30mmol/L HNO3 flow rate 1 mL/min detection UV (330 nm) after reaction with iron(lll) nitrate in acidic solution injection volume 50 pL peaks 50mg/L each of 1-hydroxyethylidene-1,1-...

Figure 3.192 Separation of aminopolyphosphonic acids. Separator coiumn ionPac AS7 eiuent 30mmol/L HNO3 injection volume 50 pL peaks 50mg/L each of DEQUEST 2010 (1), DEQUEST 2051 (2), DEQUEST 2000 (3), DEQUEST 2041 (4), and DEQUEST 2060 (5).

Figure 3.192 shows the separation of the most important aminopolyphosphonic acids that are commercialized under the trade name DEQUEST. 

In addition to aminopolyphosphonic acids, polyphosphonic acids without amino function may also be analyzed by ion chromatography. Such compounds also serve as complexing agents for alkaline-earth metals and several auxiliary group elements. As for the monophosphonic acids, 2-phosphonobutane-l,2,4-tricarboxylic acid (PBTC) is of very high industrial importance. In diphosphonic... 

Fig. 3-137. Separation of aminopolyphosphonic acids of the DEQUEST type. - Separator column lonPac AS7 chromatographic conditions see Fig.

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