scholarly journals Isotope ratio infrared spectroscopy analysis of water samples without memory effects

2021 ◽  
Vol 35 (8) ◽  
Author(s):  
Stefan Graaf ◽  
Hubert B. Vonhof ◽  
Elan J. Levy ◽  
Monika Markowska ◽  
Gerald H. Haug
Keyword(s):  
Infrared Spectroscopy ◽  
Water Samples ◽  
Isotope Ratio ◽  
Memory Effects ◽  
Spectroscopy Analysis

Comparison of isotope ratio measurement capabilities for CO2: Sample preparation and characterization by Isotope Ratio Infrared Spectroscopy

2020 ◽  
Author(s):  
Edgar Flores ◽  
Philippe Moussay ◽  
Eric Mussell Webber ◽  
Ian Chubchenko ◽  
Francesca Rolle ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
Isotope Ratio ◽  
Isotopic Ratio ◽  
Memory Effects ◽  
Low Flow ◽  
Calibration System ◽  
Sampling System ◽  
Accurate Analysis ◽  
Flow Measurements ◽  
Ratio Measurement

<p>This paper will describe the characteristics and performance of a system to prepare up to ten 50 mL samples of pure CO<sub>2</sub> with on-demand <sup>13</sup>C/<sup>12</sup>C ratios, together with an optimized calibration system for measurements by Isotope Ratio Infrared Spectroscopy (IRIS) that has allowed measurement of δ<sup>13</sup>C and δ<sup>18</sup>O values with 0.02 ‰ reproducibility (1 σ).</p><p>The needs for improved quality infrastructure and appropriate reference gases for CO<sub>2</sub> isotope ratio measurements has been a driver for recent research and development activities within the National Metrology Institutes, and the decision of the Gas Analysis Working Group of the CCQM to plan an international comparison (CCQM-P204) of capabilities of measurements of these quantities. The comparison will be coordinated by the BIPM, which has the mission of preparing the comparison samples, and the IAEA, who will assign their isotopic composition on reference scales. The BIPM has developed a preparation facility based on blending of different pure CO<sub>2</sub> sources of very different isotopic compositions, followed by cryogenic trapping and transfer to ten 50 mL cylinders. The target isotopic ratio <sup>13</sup>C/<sup>12</sup>C can be adjusted by accurate flow measurements.</p><p>A Carousel sampling system with bracketing reference gas calibration and dilution system has been designed at the BIPM to allow rapid and accurate analysis of prepared gas mixtures by IRIS. A key feature of the calibration system is to maintain identical treatment of sample and reference gases allowing two-point calibration of up to 14 samples, and appropriate flushing protocols to remove any biases from memory effects of previously sampled gases. Measurements are performed by the IRIS analyzer at a mole fraction of nominally 700 μmol/mol CO<sub>2</sub> in air, by dilution of pure CO<sub>2</sub> gas controlled by individual low-flow mass flow controllers (0.07 ml/min), and with a feedback loop to control mole fractions to ensure that differences between references and sample gas mole faction stay below 2 μmol/mol. This level of control is necessary to prevent biases in measured isotope ratios, the magnitude of which has also been studied with a sensitivity study that is also reported.</p><p>The Carousel and IRIS measurements have been validated using pure CO<sub>2</sub> samples prepared with the gas blending facility, covering a range in delta values of -1 ‰ to -45 ‰ vs VPDB, and in all cases measurement reproducibility over several days of testing of 0.02‰ or better (1 σ) were achieved for both δ<sup>13</sup>C and δ<sup>18</sup>O, with negligible memory effects.</p><p>Samples produced and characterized with the facility will be distributed to institutes participting in the CCQM-P204 comparison exrecise, with measurements foreseen in the first quarter of 2020.</p>

scholarly journals Application of Near-Infrared Spectroscopy Analysis Technology to Total Nucleosides Quality Control in the Fermented Cordyceps Powder Production Process

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Tiannv Shi ◽  
Yongmei Guan ◽  
Lihua Chen ◽  
Shiyu Huang ◽  
Weifeng Zhu ◽  
...  
Keyword(s):  
Quality Control ◽  
Infrared Spectroscopy ◽  
Production Process ◽  
Process Monitoring ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Powder Preparation ◽  
Spectroscopy Analysis ◽  
Online Process Monitoring ◽  
Online Process

Product quality control is a prerequisite for ensuring safety, effectiveness, and stability. However, because of the different strain species and fermentation processes, there was a significant difference in quality. As a result, they should be clearly distinguished in clinical use. Among them, the fermentation process is critical to achieving consistent product quality. This study aims to introduce near-infrared spectroscopy analysis technology into the production process of fermented Cordyceps powder, including strain culture, strain passage, strain fermentation, strain filtration, strain drying, strain pulverizing, and strain mixing. First, high performance liquid chromatography (HPLC) was used to measure the total nucleosides content in the production process of 30 batches of fermented Cordyceps powder, including uracil, uridine, adenine, guanosine, adenosine, and the process stability and interbatch consistency were analyzed with traditional Chinese medicine (TCM) fingerprinting, followed by the near-infrared spectroscopy (NIRS) combined with partial least squares regression (PLSR) to establish a quantitative analysis model of total nucleosides for online process monitoring of fermented Cordyceps powder preparation products. The model parameters indicate that the established model with good robustness and high measurement precision. It further clarifies that the model can be used for online process monitoring of fermented Cordyceps powder preparation products.

scholarly journals Vasorelaxation Study and Tri-Step Infrared Spectroscopy Analysis of Malaysian Local Herbs

2016 ◽  
Vol 19 (2) ◽  
pp. 145-154 ◽  
Author(s):  
Mun Fei Yam ◽  
Yung Sing Ch’ng ◽  
Chu Shan Tan ◽  
Yean Chun Loh ◽  
Mariam Ahmad ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
Spectroscopy Analysis

scholarly journals tudy on the determination of ¹⁰B/¹¹B isotope ratio in water samples by isotope dilution – inductively coupled plasma mass spectrometry (ID-ICPMS)

2021 ◽  
Vol 7 (3) ◽  
pp. 8-16
Author(s):  
Kim Dung Nguyen Thi ◽  
Thi Lien Nguyen
Keyword(s):  
Mass Spectrometry ◽  
Isotope Dilution ◽  
Water Samples ◽  
Inductively Coupled Plasma ◽  
Isotope Ratio ◽  
Isotopic Ratio ◽  
Primary Coolant ◽  
Inductively Coupled ◽  
Plasma Mass Spectrometry

The determination of 10B/11B isotope ratio and boron concentration in various watersamples using isotope dilution technique with inductively coupled plasma mass spectrometry (ICPMS) was studied. The interferences on precision and accuracy in isotopic ratio determination by ICPMS such as memory effects, dead time, spectral overlap of 12C were investigated for the selection of optimum conditions. By the addition of certain amounts of enriched 10B into samples, the 10B/11B ratio was determined through ICP-MS signal of 10B and 11B. The detection limit for 10B and 11B was experimentally obtained as 0.26 µg/L and 0.92 µg/L, respectively. The ratios of 10B/11B in measured water samples varied in the ranged between 0.1905 and 0.2484 for different matrices. This method has been then applied for the determination of boron isotopic ratio in VVER-1000 reactor-type simulated primary coolant water and in some environmental water samples.

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