Cation surface-sulfonated

The separation of the same charged compounds were also accomplished on an ethyl-pyridine bonded silica surface and 30 0% methanol/C02 mobile phases without the need of added sulfonate modifier. Anionic compounds did not elute from the ethyl-pyridinium surface that lead the authors to hypothesize that the surface was positively charged. To further test this hypothesis, the separation of the same compounds on a strong anion exchange column, silica-based propyltri-methylammonium cationic surface, which exhibits are permanent positive charge was attempted. The same retention order was observed on the strong cation exchange surface. 

The liquid chromatograph used 1n this study consisted of a Cheminert Model CMP-2K (Laboratory Data Control, Riviera Beach, FI.) which is capable of a maximum flow rate of 2 ml/min at a maximum pressure of 500 PSI. This pump has all liquid contact parts limited to glass, teflon or KEL-F materials to reduce corrosion to a minimum. The Injection valve is a Laboratory Data Control Model SU 8031 slider valve with a 0.5 ml sample loop. The injection valve is located at the top of the column to minimize dead volume. The separating column is a Laboratory Data Control type MB glass column, 30 cm long with a 2 mm bore capable of a maximum pressure of 500 PSI. The column is packed with surface sulfonated cation exchanger resin prepared in this laboratory in the following manner. 

The use of low capacity surface sulfonated cation exchange resin for the liquid chromatographic separation of aromatic amines provides a rapid analytical technique for industrial hygiene surveys. A wide variety of amines can be analyzed by the same technique with good sensitivity. 

Fig. 3-128. Schematic picture of a surface-sulfonated cation exchanger.

Table 3-24. Structural and technical properties of surface-sulfonated cation exchangers.

Fig. 3-149. Separation of divalent cations with direct conductivity detection. - Separator column surface-sulfonated cation exchanger (Benson Co., Reno, USA) eluent 0.0015 mol/L ethylenediamine + 0.002 mol/L tartaric acid, pH 4.0 flow rate 0.85 mL/min injection volume 100 pL solute concentrations 10.3 ppm Zn2+, 9.1 ppm Co2+, 16 ppm Mn2+, 16.1 ppm Cd2+, 17.1 ppm Ca2+, 16 ppm Pb2+, and 20.3 ppm Sr2+ (taken from [148]).

Fig. 3-152. Separation of heavy and transition metals on a surface-sulfonated cation exchanger. -Separator column IonPac CS2 eluent 0.01 mol/L oxalic acid + 0.0075 mol/L citric acid, pH 4.2 flow rate 1 mL/min detection photometry at 520 nm after reaction with PAR injection volume 50 pL solute concentrations 5 ppm Fe3+, 0.5 ppm Cu2+, Ni2+, and Zn2+, 1 ppm Co2+, 10 ppm Pb2+, and 5 ppm Fe2+.

The first successful polyamine separations were accomplished in the mid 70s after the introduction of surface-sulfonated cation exchangers. Fig. 3-164 displays a standard chromatogram with the separation of putrescine (1,4-diaminobutane) and cadaverine (1,5-diaminopentane) as well as spermidine (A-(3-aminopropyl-1,4-diaminobutane) and... 

In the field of cation analysis, ion-pair chromatography is the preferred method for the separation of amines of all types. While short-chain aliphatic amines (C3 to C3) and some smaller aromatic amines [39] can also be separated on surface-sulfonated cation exchangers, ion-pair chromatographic applications have been developed for the separation of structurally isomeric amines, alkanolamines, quaternary ammonium compounds, arylalkylamines, barbiturates, and alkaloids. 

The surface sulfonation of poly(styrene-divinylbenzene) beads with cross-linking ranging from 0.5 to 8 % divinylbenzene was studied by Small [27,28]. Examination of the sulfonation depth of a resin bead in terms of optimum separation of several inorganic cations was subsequently studied by Stevens and Small [29]. Ihese resins were used for the chromatographic separation of simple cations. 

Sulfonic acid polymeric, surface sulfonaled Hamilton PRP-x200, Wescan Cation R... 

The surface-sulfonated cation-exchange columns from Wescan are packed with 10 pm spherical resins with an exchange capacity of 0.1 mequiv/g. The Hamilton PRP X 200 resin has a similar capacity (0.035 mequiv/g) and is available in 3 pm, 10 pm and 12-20 pm particle size. 

These types of polymer resins are widely used as substrate materials for the manufacture of cation exchangers. Simultaneous analysis of mono- and divalent cations is not possible with surface-sulfonated cation exchangers thus, they are used for sequential analysis of alkali and alkaline earth metals. The ion-exchange capacity is determined by the degree of PS-DVB sulfonation. The characteristic structural and technical properties of... 

Table 7 Selected cation-exchange columns based on the surface-sulfonated styrene-divinylbenzene (PS-DVB).

In contrast to surface-sulfonated phases, latex cation exchangers exhibit a significantly higher chromatographic efficiency. Examples of Dionex latex cation-exchange columns are given in Table 9. 

A practical method for the separation of anions was described in the same paper [36]. This endeavor necessitated the development of a new low-capacity anion-exchange resin. It had been known for some time that cation- and anion-exchange resins have a marked tendency to clump together. Using this principle, a satisfactory anion-exchange material of low capacity was prepared by coating surface-sulfonated cation exchanger... 

The first latexed column (Ion Pac SC3) was introduced in 1985. A layer of micro latex particles, functionalized with a tertiary amine to generate positively charged sites, was attached to a surface-sulfonated polymeric bead. Then an additional layer of sulfonated latex particles was electrostatically attached to the outer surface so that the final bead had cation-exchange properties (See Figure 3.6). The smaller substrate size, together with a shorter mean free path for the analytes, produced greatly improved peak efficiencies. 

The first successful polyamine separations were accomplished in the mid-1970s with the introduction of surface-sulfonated cation exchangers. The separation of biogenic amins such as putrescine (1,4-diaminobutane), cadaverine (1,5-diaminopentane), spermidine (Al-(3-aminopropyl-l,4-diaminobutane), and spermine (Al,Al -bis-(3-aminopropyl)-l,4-diaminobutane) took more than 30 min. The required eluent comprised three buffer solutions that differed both in pH and in the trisodium citrate and sodium chloride concentration. Owing to the high ionic strength of these buffer solutions, detection could not be carried out by means of suppressed conductivity measurements. However, polyamines carry terminal NH2 groups and thus, fluorescence detection after reaction with... 

Fig. 4-1. Schematic representation of a surface-sulfonated cation exchange material.

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