Lamb John D, Simpson David, Jensen Bryce D, Gardner Joseph S, Peterson Quinn P
Department of Chemistry and Biochemistry, Brigham Young University, C-100 BNSN, Provo, UT 84602, USA.
J Chromatogr A. 2006 Jun 16;1118(1):100-5. doi: 10.1016/j.chroma.2006.01.138. Epub 2006 Mar 3.
Macrocycle-based ion chromatography provides a convenient, reliable method for the determination of perchlorate ion, which is currently of great interest to the environmental community. This study shows that effective perchlorate determinations can be made using standard conductimetric detection by combining an 18-crown-6-based mobile phase with an underivatized reversed-phase mobile phase ion chromatography (MPIC) column. One unique feature of this method is the flexibility in column capacity that is achieved through simple variations in eluent concentrations of 18-crown-6 and KOH, facilitating the separation of target analyte anions such as perchlorate. Using a standard anion exchange column as concentrator makes possible the determination of perchlorate as low as 0.2 ug/L in low ionic strength matrices. Determination of perchlorate at the sub-ug/L level in pure water and in spiked local city hard water samples with high background ion concentrations can be achieved this way. However, like other IC techniques, this method is challenged to achieve analyses at the ug/L level in the demanding high ionic strength matrix described by the United States Environmental Protection Agency (EPA) (1,000 mg/L chloride, sulfate and carbonate). We approached this challenge by use of the Cryptand C1 concentrator column, provided by Dionex Corporation, to effectively preconcentrate perchlorate while reducing background ion concentrations in the high ionic strength matrix. The retention characteristics of the concentrator column were studied in order to maximize its effectiveness for perchlorate determinations. The method makes possible the determination of perchlorate at the 5 ug/L level in the highest ionic strength matrix described by the EPA.
基于大环化合物的离子色谱法为高氯酸盐离子的测定提供了一种便捷、可靠的方法，目前该方法受到环境领域的广泛关注。本研究表明，通过将基于18-冠-6的流动相与未衍生化的反相流动相离子色谱（MPIC）柱相结合，使用标准电导检测法可以有效地测定高氯酸盐。该方法的一个独特之处在于，通过简单改变18-冠-6和氢氧化钾的洗脱液浓度，可以灵活调整柱容量，从而便于分离目标分析物阴离子，如高氯酸盐。使用标准阴离子交换柱作为富集柱，能够在低离子强度基质中测定低至0.2μg/L的高氯酸盐。通过这种方式，可以在纯水和背景离子浓度较高的加标当地城市硬水样品中测定亚微克/升水平的高氯酸盐。然而，与其他离子色谱技术一样，在由美国环境保护局（EPA）描述的苛刻的高离子强度基质（1000mg/L氯化物、硫酸盐和碳酸盐）中，该方法在微克/升水平进行分析时面临挑战。我们通过使用戴安公司提供的穴状配体C1富集柱来应对这一挑战，该柱可有效预富集高氯酸盐，同时降低高离子强度基质中的背景离子浓度。为了最大限度地提高其对高氯酸盐测定的有效性，对富集柱的保留特性进行了研究。该方法能够在EPA描述的最高离子强度基质中测定5μg/L水平的高氯酸盐。
