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北京石油化工学院2026年研究生招生接收调剂公告
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wtoily

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Sampling for AMS: Considering the rather involved procedure to strip sufficient DIC from groundwater for conventional analysis, it is of little wonder that accelerator mass spectrometry (AMS) has gained so much interest. For AMS, only about 5 mg carbon is required. This reduces the sample volume for typical groundwaters from up to 100 L for LSC to <500 mL for AMS. This tremendous advantage in sample size allows extraction in the laboratory by the same method as that for d13CDIC (see above). It also minimizes contamination by reducing the amount of sample "handling" in the field. We can also consider analysing samples that are not accessible by conventional methods, such as brines with <10 mg/L HCO3–, and high sulphate discharging at low flow rates from deep geologic settings, or porewaters in low-permeability sediments.

SAMPLING SYNOPSIS: DIC-14C for Accelerator Mass Spectrometry (AMS)
VOLUME: About 5 mg C are required for standard analysis.
EQUIPMENT: ·   Same as for 13CDIC extraction.
·   Container: acid- and deionized water- rinsed glass bottle (dried) with a silicon septum in cap (250 mL to 1 L), heavy-wall plastic or glass bottle, double-valve steel or glass cylinder.
·   NaN2 for waters with >1 to 2 mg-C/L DOC.
TECHNIQUE: ·   Samples must be collected without air contact and kept dark and cool.
·   If DOC is present in significant quantities, biological activity should be killed with NaN2.
ANALYSIS DIC is extracted from solution by acidification under vacuum, in the same manner as for d13C (above). The purified CO2 is sealed in a glass breakseal for conversion to black (elemental) carbon at the AMS facility. Accelerator mass spectrometry is basically an atom counting method. The carbon, mounted on Fe-filaments in the source of the mass spectrometer, is ionized and accelerated through a magnetic field to separate the three main isotopes. Accuracy is slight less than for high-precision gas counting, yet is more than adequate for hydrogeological purposes.
转载自:www.gochemist.cn
11楼2009-07-27 00:05:30
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hellysir

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★ ★
小木虫(金币+0.5):给个红包,谢谢回帖交流
star580(金币+1,VIP+0):谢谢回贴交流,欢迎常来 7-29 19:00
引用回帖:
Originally posted by wtoily at 2009-7-27 00:03:
看是用什么方法测吧 ?
传统方法还是比较便宜的   我所知道和经历过的 兰大就可以测  
加速器质谱比较贵  北京大学 西安黄土所 以及国外 比如 英国一些研究所 德国汉诺威大学等都可以测 一个样600 欧元左右

北京大学是可以
但西安黄土所是有一台新仪器,但从来没有做出来过数据,所以等于没有
12楼2009-07-27 09:26:36
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wtoily

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引用回帖:
Originally posted by hellysir at 2009-7-27 09:26:


北京大学是可以
但西安黄土所是有一台新仪器,但从来没有做出来过数据,所以等于没有

应该是出数据了 据说是在等大大文章的出现
ams 最基本的你就是碳14  仪器已经通过验收了 估计差不多
倒是本来预期要测Be10  似乎没有做到  
只是道听途说
13楼2009-07-28 00:05:16
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xianf09


star580(金币+1,VIP+0):谢谢回贴交流,欢迎常来 7-29 19:01
引用回帖:
Originally posted by wtoily at 2009-7-28 00:05:

应该是出数据了 据说是在等大大文章的出现
ams 最基本的你就是碳14  仪器已经通过验收了 估计差不多
倒是本来预期要测Be10  似乎没有做到  
只是道听途说

首先声明,我就是西安黄土室的。我个人觉得有些事情还是要根据事实调查,碳14 在黄土室的测试没任何问题,至少报导了2000以上的数据。当然不排除初期可能因为仪器调试积压了一点样品没有给同行及时报导数据,有人可能有些意见。另外10Be数据早就报导了数据,并发表了系列成果。法国搞冰心10Be的大家Rasibeck已在西安测了不少高质量数据,并专门致信给其同行推荐西安加速器对10Be的一流测试水平,今年又带来近1000个样品。

现在国内有些人因为各种历史原因老是在造谣蒙蔽视听,无言。。。。。。

我个人非常欢迎大家来西安测试样品。

[ Last edited by xianf09 on 2009-8-10 at 15:48 ]
14楼2009-07-29 17:37:16
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Franklz

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小木虫(金币+0.5):给个红包,谢谢回帖交流
Be10的文章早就出了 而且带数据
Weijian Zhou, Alfred Priller, J Warren Beck, Zhengkun Wu, Maobai Chen, Zhisheng An, Walter Kutschera, Feng Xian, Huagui Yu, Lin Liu, Disentangling geomagnetic and precipitation signals in an 80-kyr Chinese loess record of 10Be RADIOCARBON 49(2007) 139–160.
下载连接:
http://www.llqg.ac.cn/admin/uppic/2007611112426.pdf
引用回帖:
Originally posted by wtoily at 2009-7-28 00:05:

应该是出数据了 据说是在等大大文章的出现
ams 最基本的你就是碳14  仪器已经通过验收了 估计差不多
倒是本来预期要测Be10  似乎没有做到  
只是道听途说

15楼2009-08-03 10:22:31
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wtoily

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小木虫(金币+0.5):给个红包,谢谢回帖交流
引用回帖:
Originally posted by Franklz at 2009-8-3 10:22:
Be10的文章早就出了 而且带数据
Weijian Zhou, Alfred Priller, J Warren Beck, Zhengkun Wu, Maobai Chen, Zhisheng An, Walter Kutschera, Feng Xian, Huagui Yu, Lin Liu, Disentangling geomagnetic and pre ...

呵呵  
谢谢  刚好拜读一下
16楼2009-08-03 21:03:11
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支持!
17楼2009-08-04 09:56:12
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