A high-performance, safer and semi-automated approach for the δ18O analysis of diatom silica and new methods for removing exchangeable oxygen
A high-performance, safer and semi-automated approach for the δ18O analysis of diatom silica and new methods for removing exchangeable oxygen
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DOI：
10.1002/rcm.4689
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发表时间：
2010-09-01
影响因子：
2
通讯作者：
Hubberten, H. -W.
中科院分区：
文献类型：
--
作者：
Chapligin, B.;Meyer, H.;Hubberten, H. -W.
沉积物岩心中硅藻二氧化硅氧同位素组成的测定对于古气候重建非常重要，特别是在非碳酸盐沉积物中，因为那里没有介形类和有孔虫等其他生物指示剂。由于目前大多数可用的分析技术都是耗时且劳动密集型的，因此我们开发了一种新的、更安全、更快速的半自动化在线方法来测量生物二氧化硅中的氧同位素。改进包括控制测量程序的软件和使用 CO2 激光器远程记录 BrF5 下样品反应的摄像机。由于激光氟化装置布置在与操作员分开的房间内的通风橱下，因此可保证最大程度的安全。已经开发出一种新的程序，用于使用斜坡脱气去除生物二氧化硅中的可交换含水成分。在同位素分析之前，将样品板加热至 1100 摄氏度，并在 He 气流下（惰性气流脱水法 - iGFD）在 7 小时内冷却至 400 摄氏度。测试了已知同位素组成的两个石英和两个生物二氧化硅样品（类似于 4.5 毫克）。同位素组成可在可接受的误差范围内重现；石英样品的平均标准偏差为
The determination of the oxygen isotope composition of diatom silica in sediment cores is important for paleoclimate reconstruction, especially in non-carbonate sediments, where no other bioindicators such as ostracods and foraminifera are available. Since most currently available analytical techniques are time-consuming and labour-intensive, we have developed a new, safer, faster and semi-automated online approach for measuring oxygen isotopes in biogenic silica. Improvements include software that controls the measurement procedures and a video camera that remotely records the reaction of the samples under BrF5 with a CO2 laser. Maximum safety is guaranteed as the laser-fluorination unit is arranged under a fume hood in a separate room from the operator. A new routine has been developed for removing the exchangeable hydrous components within biogenic silica using ramp degassing. The sample plate is heated up to 1100 degrees C and cooled down to 400 degrees C in 7 h under a flow of He gas (the inert Gas Flow Dehydration method - iGFD) before isotope analysis. Two quartz and two biogenic silica samples (similar to 4.5 mg) of known isotope composition were tested. The isotopic compositions were reproducible within an acceptable error; quartz samples gave a mean standard deviation of