共 18 条
A pulsed injection parahydrogen generator and techniques for quantifying enrichment
被引:86
作者:
Feng, Bibo
[1
,2
]
Coffey, Aaron M.
[1
,4
]
Colon, Raul D.
[1
,3
]
Chekmenev, Eduard Y.
[1
,2
,4
]
Waddell, Kevin W.
[1
,2
]
机构:
[1] Vanderbilt Univ, Inst Imaging Sci, Nashville, TN 37232 USA
[2] Vanderbilt Univ, Dept Radiol & Radiol Sci, Nashville, TN 37232 USA
[3] Vanderbilt Univ, Dept Phys, Nashville, TN 37232 USA
[4] Vanderbilt Univ, Dept Biomed Engn, Nashville, TN 37232 USA
基金:
美国国家卫生研究院;
关键词:
PASADENA;
Parahydrogen;
Orthohydrogen;
Hyperpolarization;
SABRE;
PHIP;
PARA-HYDROGEN;
POLARIZATION;
D O I:
10.1016/j.jmr.2011.11.015
中图分类号:
Q5 [生物化学];
学科分类号:
071010 ;
081704 ;
摘要:
A device is presented for efficiently enriching parahydrogen by pulsed injection of ambient hydrogen gas. Hydrogen input to the generator is pulsed at high pressure to a catalyst chamber making thermal contact with the cold head of a closed-cycle cryocooler maintained between 15 and 20 K. The system enables fast production (0.9 standard liters per minute) and allows for a wide range of production targets. Production rates can be systematically adjusted by varying the actuation sequence of high-pressure solenoid valves, which are controlled via an open source microcontroller to sample all combinations between fast and thorough enrichment by varying duration of hydrogen contact in the catalyst chamber. The entire enrichment cycle from optimization to quantification and storage kinetics are also described. Conversion of the para spin-isomer to orthohydrogen in borosilicate tubes was measured at 8 min intervals over a period of 64 h with a 12 T NMR spectrometer. These relaxation curves were then used to extract initial enrichment by exploiting the known equilibrium (relaxed) distribution of spin isomers with linear least squares fitting to a single exponential decay curve with an estimated error less than or equal to 1%. This procedure is time-consuming, but requires only one sample pressurized to atmosphere. Given that tedious matching to external references are unnecessary with this procedure, we find it to be useful for periodic inspection of generator performance. The equipment and procedures offer a variation in generator design that eliminate the need to meter flow while enabling access to increased rates of production. These tools for enriching and quantifying parahydrogen have been in steady use for 3 years and should be helpful as a template or as reference material for building and operating a parahydrogen production facility. (C) 2011 Elsevier Inc. All rights reserved.
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页码:258 / 262
页数:5
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