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A high-capacity carboxylic acid-functionalized resin prepared by ring-opening metathesis polymerization containing cis-1,4-butanedioic acid (succinic acid) units was used for the extraction of rare-earth elements (REEs) from rock digests. Extraction efficiencies measured by means of ICP-AES were found to be in the range of 90−100% for standards containing 5 and 500 ppb of each REE, respectively. The optimum extraction pH was found to be between 5.3 and 5.5. Three different rock standard reference materials (SRMs), GSR-1 granite, GSR-2 andesite, and GSR-3 basalt, were digested by fusion of the corresponding rock with lithium metaborate (LiBO2) and subsequent dissolution in nitric acid. As a consequence of the different compositions of the three investigated SRMs, the resulting digest showed different concentrations of the REEs as well as of SiO2, Fe, Al, Mg, and Ca. The entire extraction procedure was additionally supported by masking of the interfering metal ions using 5-sulfosalicylic acid. Small amounts of methanol were added to prevent silicate from precipitating. Following this setup, REEs occurring in the digest solutions in the range of 40 ppt to 150 ppb were retained selectively, with recoveries ranging for most elements from 75 to 110%. The high performance of the entire system is underlined by the fact that relative standard deviations were <10% for most of the REEs.

Homopolymers of 7-oxanorborn-2-ene-5,6-dicarboxylic anhydride (ONDCA) and norborn-2-ene (NBE), respectively, as well as copolymers of ONDCA and NBE with well-defined block sizes and molecular weights have been prepared by ring-opening metathesis polymerization (ROMP) using initiators of the type Cl 2 Ru(PR 3 ) 2 (CHAr′) (R ) phenyl, cyclohexyl, Ar′ ) C 6 H 5 , p-F-C 6 H 5 ). Despite the fact that ONDCA is not initiated stoichiometrically by the initiators employed, the block-copolymers are well-defined in the case where the polymerization is started with NBE. The linear polymers and copolymers were coated onto various vinylsilanized silica materials and subsequently cross-linked employing azobis(isobutyronitrile) (AIBN). The influence of particle size, pore diameter and volume, the specific surface of the inorganic carrier, the influence of the block sizes, and the amounts of coating on the chemical stability of the resulting materials as well as on the separation efficiency and selectivity have been studied. The high hydrophilicity of any ONDCA-containing polymer or copolymer ensures a strong interaction of the mobile phase with the material even in the case of a low organic solvent content (<2%). The high selectivity of the stationary phases is demonstrated by fast baseline separations (6-10 min) of various isomeric anilines and lutidines as well as hydroxyquinolines. The complementary use of apolar, NBE-based coatings and highly polar, pure ONDCA-based coatings allows an in depth discussion of the separation mechanism. Tests designed to detect underivatized, accessible surface silanol groups (Engelhardt test) confirmed the quantitative coating of the surface, which also accounts for the significantly elevated pH stability compared to standard silica materials.

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