Błażewicz Anna, Klatka Maria, Dolliver Wojciech, Kocjan Ryszard
Department of Analytical Chemistry, Medical University of Lublin, 4a Chodźki St., 20-093 Lublin, Poland.
Department of Pediatric Endocrinology and Diabetology, Medical University of Lublin, Poland.
J Chromatogr B Analyt Technol Biomed Life Sci. 2014 Jul 1;962:141-146. doi: 10.1016/j.jchromb.2014.05.022. Epub 2014 May 19.
A fast, accurate and precise ion chromatography method with pulsed amperometric detection was applied to evaluate a variety of parameters affecting the determination of total iodine in serum and urine of 81 subjects, including 56 obese and 25 healthy Polish children. The sample pretreatment methods were carried out in a closed system and with the assistance of microwaves. Both alkaline and acidic digestion procedures were developed and optimized to find the simplest combination of reagents and the appropriate parameters for digestion that would allow for the fastest, least time consuming and most cost-effective way of analysis. A good correlation between the certified and the measured concentrations was achieved. The best recoveries (96.8% for urine and 98.8% for serum samples) were achieved using 1ml of 25% tetramethylammonium hydroxide solution within 6min for 0.1ml of serum/urine samples. Using 0.5ml of 65% nitric acid solution the best recovery (95.3%) was obtained when 7min of effective digestion time was used. Freeze-thaw stability and long-term stability were checked. After 24 weeks 14.7% loss of iodine in urine, and 10.9% in serum samples occurred. For urine samples, better correlation (R(2)=0.9891) of various sample preparation procedures (alkaline digestion and application of OnGuard RP cartidges) was obtained. Significantly lower iodide content was found in samples taken from obese children. Serum iodine content in obese children was markedly variable in comparison with the healthy group, whereas the difference was less evident when urine samples were analyzed. The mean content in serum was 59.12±8.86μg/L, and in urine 98.26±25.93 for obese children when samples were prepared by the use of optimized alkaline digestion reinforced by microwaves. In healthy children the mean content in serum was 82.58±6.01μg/L, and in urine 145.76±31.44μg/L.
采用快速、准确且精密的离子色谱法结合脉冲安培检测法，对影响81名受试者血清和尿液中总碘测定的各种参数进行评估，其中包括56名肥胖波兰儿童和25名健康波兰儿童。样品预处理方法在封闭系统中借助微波进行。开发并优化了碱性和酸性消解程序，以找出试剂的最简单组合以及合适的消解参数，从而实现最快、最省时且最具成本效益的分析方式。认证浓度与测量浓度之间具有良好的相关性。对于0.1ml血清/尿液样品，在6分钟内使用1ml 25%氢氧化四甲铵溶液可实现最佳回收率（尿液为96.8%，血清样品为98.8%）。使用0.5ml 65%硝酸溶液，当有效消解时间为7分钟时可获得最佳回收率（95.3%）。检查了冻融稳定性和长期稳定性。24周后，尿液中碘损失了14.7%，血清样品中碘损失了10.9%。对于尿液样品，各种样品制备程序（碱性消解和使用OnGuard RP柱）具有更好的相关性（R² = 0.9891）。肥胖儿童采集的样品中碘化物含量显著更低。与健康组相比，肥胖儿童血清碘含量明显多变，而分析尿液样品时差异不太明显。当通过优化的微波强化碱性消解制备样品时，肥胖儿童血清中的平均含量为59.12±8.86μg/L，尿液中为98.26±25.93μg/L。健康儿童血清中的平均含量为82.58±6.01μg/L，尿液中为145.76±31.44μg/L。
