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The chromatographic separation properties of long, thin adsorption tubes enable substance-specific quantitative enrichment and reduction to be achieved when sampling and thermal desorption are carried out in the same flow direction. The specific retention volumes, and also the breakthrough and peak end volumes, of 69 compounds in the boiling range between-164 and 126°C and of a relative molecular mass between 16 and 119 were determined at temperatures between 30 and 130°C: normal alkanes, isoalkanes, cycloalkanes, alkenes, polyenes, alkynes, aromatics, ethers, alcohols, aldehydes, ketones, carboxylic acids and their esters, nitroalkanes, O-heterocycles, S-heterocycles, chloroalkanes, water, nitrogen monoxide, nitrogen dioxide, carbon dioxide, and sulfur dioxide. The correlation between adsorbent temperature and specific retention volume of these components, presented in the form of diagrams, permits the required quantity of adsorbent to be determined for a given sample volume. Contrary to literature sources, even extremely volatile compounds such as propane, propene, methanol, formaldehyde, formic acid, and chloromethane can be quantitatively retained on Tenax provided the operating conditions are appropriately selected. 相似文献
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二苯并-18-冠-6-甲醛聚合物柱色谱分离富集化学发光法测定痕量金 总被引:5,自引:0,他引:5
研究了用一种新的高分子冠醚聚合物(二苯并-18-冠-6-甲醛聚合物)作为色谱柱的固定相,分离富集痕量金,再用化学发光法进行测定;在盐酸介质中,高分子冠醚对金的吸附率可达100%,吸附的金可被硫脲完全解吸,吸附容量为19.40mg/g;化学发光法测定操作简便,效果令人满意;研究结果表明:把高分子冠醚聚合物作为分离富集手段与具有高灵敏度的化学发光法结合进行痕量分析是一种很有前途的方法。 相似文献
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Summary A simple gas chromatographic method has been developed for analysis of hydrogen sulfide in hydrogen at the 0.5 to 100 ppm level. After enriching the traces of hydrogen sulfide by absorption in a gas loop packed with the chosen column support at 77 K it was determined by using a Chromosorb G column with silicone 550 and phthalic anhydride as liquid phases, hydrogen as carrier gas and a thermal conductivity detector. The detection limit was found to be about 0.5 ppm of hydrogen sulfide. 相似文献
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利用合成的巯基含量为2.2~2.5%的高巯基粉状巯基棉,对水中超痕量汞进行富集测定。流速可达100mL·min~(-1),检出限为0.5×10~(-12),加标回收率为90~104%。 相似文献
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2-{[1-(3,4-Dihydroxyphenyl)methylidene]amino}benzoic acid (DMABA) was loaded on Amberlite XAD-16 (AXAD-16) via azo linker and the resulting resin AXAD-16-DMABA explored for enrichment of Zn(II), Mn(II), Ni(II), Pb(II), Cd(II), Cu(II), Fe(III) and Co(II). The optimum pH values for extraction are 6.5-7.0, 5.0-6.0, 5.5-7.5, 5.0-6.5, 6.5-8.0, 5.5-7.0, 4.0-5.0 and 6.0-7.0, respectively. The sorption capacity was found between 97 and 515 μmol g−1 and the preconcentration factors from 100 to 450. Tolerance limits for foreign species are reported. The kinetics of sorption is fast as t1/2 is ≤5 min. The chelating resin can be reused for 50 cycles of sorption-desorption without any significant change (<1.5%) in the sorption capacity. The limit of detection values (blank +3 s) are 1.12, 1.38, 1.76, 0.67, 0.77, 2.52, 5.92 and 1.08 μg L−1 for Zn(II), Mn(II), Ni(II), Pb(II), Cd(II), Cu(II), Fe(III) and Co(II), respectively. The enrichment on AXAD-16-DMABA coupled with monitoring by flame atomic absorption spectrometry (FAAS) is used to determine all the metal ion ions in river and synthetic water samples, Co in vitamin tablets and Zn in milk samples. 相似文献
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A microorganism Agrobacterium tumefacients as an immobilized cell on a solid support was presented as a new biosorbent for the enrichment of Fe(III), Co(II), Mn(II) and Cr(III) prior to flame atomic absorption spectrometric analysis. Amberlite XAD-4 was used as a support material for column preconcentration. Various parameters such as pH, amount of adsorbent, eluent type and volume, flow rate of sample solution, volume of sample solution and matrix interference effect on the retention of the metal ions have been studied. The optimum pH for the sorption of above mentioned metal ions were about 6, 8, 8 and 6, respectively. The loading capacity of adsorbent for Co(II) and Mn(II) were found to be 29 and 22 μmol g−1, respectively. The recoveries of Fe(III), Co(II), Mn(II) and Cr(III), under the optimum conditions were found to be 99 ± 3, 99 ± 2, 98 ± 3 and 98 ± 3%, respectively, at the 95% confidence level. The limit of detection was 3.6, 3.0, 2.8 and 3.6 ng ml−1 for Fe(III), Co(II), Mn(II) and Cr (III), respectively, by applying a preconcentration factor of 25. The proposed enrichment method was applied for metal ion determination from water samples, alloy samples, infant foods and certified samples such as whey powder (IAEA-155) and aluminum alloy (NBS SRM 85b). The analytes were determined with a relative error lower than 10% in all samples. 相似文献
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《Journal of separation science》2003,26(17):1527-1532
In this paper, a setup called micro‐column solid phase extraction (MicroSPE) was developed to enhance the sensitivity of capillary electrophoresis. The setup consists of a manual pump, several insulin syringes, and a Teflon extraction cartridge. The cartridge was made of 2–4 mm irregular C18 solid phase materials in a Teflon tube (375 μm ID) with glass fiber frits. Two pieces of capillary tubing were connected to both the ends of the cartridge. Using sulindac‐spiked urine as the test sample, the extraction and analytical conditions were investigated in detail. When 1 μL 70/30 methanol/water was applied as the elution solvent, satisfactory results could be obtained. The internal standard method was used to quantitatively determine the compound in urine. The detection limit for sulindac was 2.9 ng/mL and the enrichment factor reaches more than 260. The result illustrates that the MicroSPE setup has a significant concentrating effect and is suitable for preconcentrating and cleaning‐up samples with complex matrices. 相似文献