在大浓度内测量D13C高精度

Bulk stable isotope analysis of a wide variety of organic and inorganic materials for C, N, H, and S & O is generally carried out over a varied assortment of applications. For multi-element analysis from a single sample, the dynamic range of the instrumentation must be great, as organic substances usually have large C/N and C/S ratios.

同位素比的经验与Elementar的元素分析仪的前瞻性技术相结合，Isoprime Vision和Isoprime Precision设备为检查具有较高元素比率的样品提供了出色的机会。

Elementar’s elemental analyzers are the only systems able to execute truly multi-elemental isotope analysis from just one sample. The exclusive Advanced Purge and Trap technique (APT) in combination with their high dynamic range inimitably offers easy stable isotope analysis of CHNS of substances with large differences in element concentration at the same time.

It is simple to increase the sample weight to examine substances with a very low S or N content. The result of this larger sample weight is that the more plentiful elements reach a greater concentration. To achieve this, the等异理and等级精度设备具有带有其他仪器范围的两倍的放大器以及全自动样品气体稀释系统。

该作品将确定中心稀释系统如何允许对各种元素浓度的简单分析而无需承认性能，从而确保即使在最具挑战性的分析试验中，也可以确保非常准确。

Advanced Purge and Trap (APT) Technology

Elementar的独家APT技术是一种用于定量分离燃烧气体的先驱色谱法。它利用多达三个Adsorb Co的气体选择性捕获柱₂, H₂O, and SO₂in particular while allowing clearance to other combustion gases. Once the column is heated, the adsorbed gas is let go.

The quick pace of heating for the gas desorption guarantees sharp peaks and exceptional signal-to-noise ratios, leading to revolutionary levels of precision and sensitivity (Figure 1). Unlike with isothermal GC-based analyzers, a total distinction of peaks is always attained, even at greater ratios of elemental content and elemental concentration.

图1。Example of the peak focusing effect of the APT technology for δ³⁴S分析0.5 mg（GC）和0.3 mg（APT）硫酸钡样品。

APT技术已被证明没有同位素分馏，并且与质谱检测结合在一起，能够解决高达10,000的C/N和C/S比率：1。与GC列相比，APT列可以可以加载高达250倍，从而导致出色的样品灵活性。

The higher quality peak-shapes and greater sensitivity response of the APT technology requires an amplifier with a powerful range and automated dilution of the sample gas.

CentrION CF Interface System

中心是连续流（CF）界面系统，它可以自动管理元素分析仪运输的样品气体。通过将高精度质量流量控制器应用于完全自动化的控制下，氦气和监测气体的电流可以以很高的精度进行管理。

CentrION is made up of two key elements:

• The monitoring gas injection structure conveys up to six monitoring gases into the ion source for performance examination.
• The sample dilution function condenses high concentration sample gases from the elemental analyzer using designated sample types.

Stable isotope ratio analysis makes use of the delicate deviations in isotope abundance stemming from chemical, biological or physical procedures. It is vital that the analytical equipment itself does not yield any fractionation, as this can prejudice the stable isotope results.

开发了Centrion，以确保稀释功能通过使用多种稀释系统的稀释功能绝对没有同位素分馏。

Performance of the Dilution System

A carefully regulated glutamic acid standard of known isotopic composition was primed over a 20 fold range in sample sizes and examined. The sample gas was kept undiluted for the smallest sample weight (dilution rate = 0), while for larger sample weights, glutamic acid was examined over a range of dilution regimes, so that a comparable signal for the isotope ratio studies was attained.

样品气的稀释仅对δ进行¹³C analyses. The findings of the δ¹³C studies are illustrated in Figure 2 and Table 1. The results demonstrate that the δ¹³谷氨酸的C比率可以用高度的精度确定。

图2。δ¹³C analyses of glutamic acid samples with different sample weights and dilution rates. The red markers depict the individual analyses, the solid line the mean value of all analyses and the dotted line the standard 2-sigma expected precision ofδ¹³C isotope ratio analyses. The analyses show an exceptional precision over a very large range in sample sizes.

Table 1.δ¹³C analyses of glutamic acid samples with different sample weights and dilution rates.

在δ之间未检测到方差¹³C isotope ratio without dilution of the sample gas and the ratios for altered dilution rates, indicating that the diluter does not fractionate the sample gas.

The minimal standard deviation of the whole series of glutamic acid analyses (0.04), demonstrates the outstanding performance of the centrION system for a wide variety of sample weights. For the sample weights illustrated in Table 1, the capacity of the APT column for CO₂远非筋疲力尽。

To illustrate, for the examination of δ³⁴S in wood with a sulfur content down to 50 ppm, 40 mg wood was studied, matching with an absolute carbon content of around 20 mg. Despite a great rate of dilution, these studies will automatically lead to comparatively large CO₂峰，这不会引起100 V放大器的问题等异理and isoprime precisION。

可靠的稀释

Isotope ratios of samples with extremely high C/N or C/S ratios can easily be studied in a single analysis run, with confidence, thanks to the isoprime visION and isoprime precisION devices, with a built-in centrION dilution system.

A great sample weight must be conveyed into the instrument to allow for a reliable signal to noise ratio for the element with the lowest concentration. For elemental analyzers which use isothermal chromatographic gas separation, as opposed to the cutting-edge purge and trap technology of the isoprime visION and isoprime precision, this would cause issues.

为了避免在同位素比的测量值（例如，高碳浓度）中增加放大器的负担¹³C analyses can be diluted without any impact on the isotope ratio results, allowing the operator a greater degree of freedom in how they opt to carry out their analysis.

The outstanding performance of the centrION dilution system ensures that the studies of samples with great variations in element concentrations can be carried out in a single analysis run. Using varied dilution rates for diverse compounds, up to four stable isotope ratios (δ¹³C, δ¹⁵N, δ³⁴s和δ²H) can be examined from a single sample.

This makes sample preparation and analysis far less time-consuming, resulting in considerably lower running costs and enhanced instrument output.

Further Reading

有关更多信息，请探讨有关高级清除和陷阱技术以及大型动态范围放大器的这些技术说明：

• TN considerations of dynamic range in stable isotope analysis - part 1: intrinsic isotope abundance
• TN高级清除和陷阱技术

This information has been sourced, reviewed and adapted from materials provided by Elementar Analysensysteme GmbH.

For more information on this source, please visitElementar Analysensysteme GmbH。