Determination of nitrate at the ng/g level in Antarctic snow samples with ion chromatography and isotope dilution mass spectrometry
Determination of nitrate at the ng/g level in Antarctic snow samples with ion chromatography and isotope dilution mass spectrometry
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DOI：
10.1007/bf01105161
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发表时间：
1988-02
期刊：
影响因子：
--
通讯作者：
J. Neubauer;K. Heumann
中科院分区：
文献类型：
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作者：
J. Neubauer;K. Heumann
1987年1 - 2月在德国南极考察站Georgvon-Neumayer用离子色谱法测定了南极Ekstr 6 m冰架雪和白霜样品中硝酸盐的含量。为了进行比较，同位素稀释质谱法的样品制备也在德国站进行，而质谱测量则在里根斯堡进行。在40-190 ng/g范围内，两种方法的重复性为1%-5%。在三组雪芯样品中，两种方法的结果非常一致，平均偏差为0.1%。对11个白霜和地面雪样品，离子色谱值与同位素稀释质谱值的平均相对偏差为-10%。白霜样品中的硝酸盐浓度最高，平均值为548纳克/克。硝酸盐沉积年龄的顺序为：新雪（206纳克/克），旧的地表雪（146纳克/克），雪芯雪（61纳克/克）。随着样品年龄的增长，硝酸盐浓度逐渐降低，这是硝酸盐在雪沉积后重新排放到大气中的结果。硝酸盐浓度的季节性变化与夏季最大值和冬季最小值观察到的雪芯样品。今天从南极洲所有地区公布的分析数据的准确结果，只能通过应用独立的方法来保证，例如，通过离子色谱法和同位素稀释质谱法，如本工作所示。
Nitrate traces in Antarctic snow and hoar-frost samples, which were collected on the Ekstr6m ice shelf during January and February, 1987, were determined with ion chromatography at the German Antarctic station" Georgvon-Neumayer". For comparison, sample preparations for isotope dilution mass spectrometry were also carried out at the German station whereas the mass spectrometric measurements took place in Regensburg. Comparable reproducibilities of 1%-5% were found for both methods of analysing nitrate concentrations in the range of 40-190 ng/g. An excellent agreement of the results of both methods with an average deviation of 0.1% was found in three sets of firn core samples. The average relative deviation of the ion chromatographic values from those of isotope dilution mass spectrometry was-10% for eleven hoar-frost and surface snow samples. The highest nitrate concentrations were analysed in hoar-frost samples with an average value of 548 ng/g. The following order, which corresponds to the age of nitrate depositions, was: new snow (206 ng/g), old surface snow (146 ng/g), and snow from firn cores (61 ng/g). The decreasing concentration with the age of samples is the result of re-emission of nitrate into the atmosphere after its deposition by snow. A seasonal variation of the nitrate concentration with a summer maximum and a winter minimum was observed for firn core samples. Accurate results of analytical data, which are published from all parts of Antarctica today, can only be guaranteed by the application of independent methods, eg, by ion chromatography and isotope dilution mass spectrometry as it is shown in this work.