沈川洲臺灣大學：地質科學研究所呂佳蓉Lu, Chia-JungChia-JungLu2007-11-262018-06-282007-11-262018-06-282006http://ntur.lib.ntu.edu.tw//handle/246246/54853我們已成功建立一套準確度達千分比等級之碳酸鹽類Mg/Ca及Sr/Ca的磁場式感應耦合電漿質譜儀分析技術。利用800瓦無線電波功率的冷電漿技術減低頻譜干擾，並搭配高敏感度和高穩定度的溼式標本導入系統。鎂鈣和鍶鈣比值（24Mg/43Ca和86Sr/43Ca）是藉由脈衝式計數器量測之24Mg, 43Ca 及86Sr離子訊號強度比值計算而得，並使用標準樣品穿插校正法校正儀器的質量分化及低頻飄移的現象。而除鎂鈣及鍶鈣比值之外，標本中的鋁鈣（Al/Ca）、錳鈣（Mn/Ca）、鐵鈣（Fe/Ca）、鎘鈣（Cd/Ca）和鋇鈣（Ba/Ca）比值也可以同時測量。在本方法中發現到有三種基質效應，包含（1）硝酸濃度影響各種元素的訊號強度及比值與測量，當硝酸由1-6%增加時，元素比值變化趨緩，最後選擇使用5%之硝酸做為實驗時固定濃度;（2）鎂鈣比值測定受到鈣濃度影響，當鈣濃度介於0.5-2.5 ppm時，鎂鈣比值會造成2.5%的變化，當鈣濃度高於3 ppm時，此基質效應僅有輕微的影響；（3）不同的鍶鈣比值亦會對鎂鈣比值造成0.18% mmol/mol的偏差，主要原因是受到Sr++ 二價離子的形成干擾到43Ca+ 離子強度進而影響到鎂鈣比值，所幸，此影響只會對有孔蟲和珊瑚的鎂鈣比值造成約小於0.1%的偏差。此方法的測量準確度可達0.1-0.2%，標準溶液和標本的重覆測試結果顯示鎂鈣比值的分析再現性為0.45%，鍶鈣比值則為0.35%（2RSD)；此結果相對於有孔蟲鎂溫度計的誤差為0.05 ℃，珊瑚鍶溫度計的誤差為0.5 ℃。本方法的標本需求量僅為2 µg，且分析產能為每小時10個標本，加上簡便的事前準備工作，本技術優於其他元素比值分析分法。A permil-level analytical technique for determination of carbonate Mg/Ca and Sr/Ca ratios using inductively coupled plasma sector-field mass spectrometry (ICP-SF-MS, Thermo Electron ELEMENT2) has been established. Cold plasma technique with a RF power of 800-W were employed to diminish spectral interference. A wet introduction system with Scott-type double-pass spray chamber and an ESI micro-nebulizer with a sample uptake rate of 50 µl/min were used, which can offer low blank and high stability. Intensities of ion beams, 24Mg, 43Ca and 86Sr, were detected in pulse-counting mode. Mg/Ca and Sr/Ca ratios were determined directly from intensity ratios using external, matrix-matched standard to correct for mass discrimination and low-frequency ratio drift. Al/Ca, Mn/Ca, Fe/Ca, Cd/Ca, Ba/Ca and Th/Ca were also determined. Three different matrix effects are observed. (1) Acid effect on the elemental intensities and ratios decreases with increasing HNO3 from 1-6%. 5% HNO3 was suggested be used for routine measurement. (2) For the effect of Ca level, Mg/Ca ratio varies by 2.5% with [Ca] from 0.5-2.5 ppm and changes insignificantly for [Ca] higher than 3 ppm. (3) Different Sr/Ca slightly affects Mg/Ca determination with a slope of 0.18% per mmol/mol. It is caused by the formation of 86Sr double charged ions, which biases the measurement of 43Ca+ and affects the accuracy of Mg/Ca analysis. This effect causes only 0.1% or less for Mg/Ca ratio in both foraminiferal and coral samples. Replicate measurements made on standards and samples show that our method can give an internal precision of 0.1-0.2% (2RSD). Reproducibility of 0.45% for Mg/Ca and 0.35% for Sr/Ca can be attained. The corresponding errors are 0.05 ℃ for foraminiferal Mg thermometer and 0.5 ℃ for coral Sr thermometer. Advantages of this new technique include a small sample size of only 2 µg and high throughput of 10 samples per hour.Page Table of Contents.........................................I List of Figures..........................................II List of Tables...........................................IV 摘要......................................................1 Abstract..................................................2 Chapter 1 Introduction.....................................3 Chapter 2 Experiment Method................................5 2.1 Chemistry.............................................5 2.1.1 Plastic-ware ........................................5 2.1.2 Standards...........................................5 2.1.3 Samples and pre-treatment...........................7 2.2 Instrumentation.......................................8 2.2.1 Sample introduction system..........................8 2.2.2 ICP-SF-MS (Element2)................................9 2.3 Data acquisition.....................................10 2.3.1 Coral..............................................10 2.3.2 Foraminifer........................................10 2.3.3 Other carbonate....................................10 Chapter 3 Result and Discussion...........................13 3.1 Spectral interference................................13 3.2 Mass discrimination and ratio drift..................16 3.3 Measurement sequence.................................18 3.4 Matrix effects .......................................20 3.4.1 Acid matrix effect.................................20 3.4.2 Matrix effect of [Ca] on Mg/Ca and Sr/Ca ratios....25 3.4.3 Matrix effects of Mg level on Sr/Ca and Sr level on Mg/Ca....................................................28 3.5 Reproducibility and sample size......................30 3.6 Comparison with other techniques.....................32 3.7 Applications.........................................35 3.7.1 Foraminiferal samples..............................35 Chapter 4 Conclusion...................................36 Reference ................................................371526309 bytesapplication/pdfen-US鎂鈣比值鍶鈣比值有孔蟲珊瑚磁場式感應耦合電漿質譜儀Mg/CaSr/CaICP-MSForaminiferaCoralthesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/54853/1/ntu-95-R93224106-1.pdf