[Show abstract][Hide abstract] ABSTRACT: We present a Cs atomic magnetometer with a sensitivity of 150fT/Hz(1/2) operating near room temperature. The nuclear magnetic resonance (NMR) signal of 125μL tap water was detected at an ultralow magnetic field down to 47nT, with the signal-to-noise ratio (SNR) of the NMR signal approaching 50 after eight averages. Relaxivity experiments with a Gd(DTPA) contrast agent in zero field were performed, in order to show the magnetometer's ability to measure spin-lattice relaxation time with high accuracy. This demonstrates the feasibility of an ultralow field NMR spectrometer based on a Cs atomic magnetometer, which has a low working temperature, short data acquisition time and high sensitivity. This kind of NMR spectrometer has great potential in applications such as chemical analysis and magnetic relaxometry detection in ultralow or zero fields.
Journal of Magnetic Resonance 10/2013; 237C:158-163. · 2.30 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Pleasant flavor and nutritional benefits of vegetable oils lead to an increase in their consumption amount. In addition, due to being apparently similar to commercially qualified vegetable oils (QVOs), used frying oil (UFO) is added into it to seek high profit by the unscrupulous traders. Thus, the authenticity assurance of commercial oil and fat products remains a challenge to scientists both in terms of its health and commercial perspectives. This work focused on using low field nuclear magnetic resonance (LF-NMR) to discriminate the adulteration of commercial corn, peanut, rapeseed, and soybean oils with two kinds of UFOs. The differences between the transverse relaxation distributions (T 2 distributions) of qualified oil and UFO were in the appearance of the third peak (A), which could be assigned to polymer products that were produced during the deep-fat frying process and the shift of T 2 value of the peaks. In addition, the A peak area accounted for the whole area of peaks linearly increasing along with the increase in adulteration proportion. Based on the changes of peak area, a simple linear equation was built and the determination coefficients (R 2) were all higher than 0.93. Therefore, as a rapid, convenient, and nondestructive method, LF-NMR application could be used to detect adulteration of vegetable oils with UFO.
Food and Bioprocess Technology 09/2013; 6(9):2562-2570. · 4.12 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: In this review we focus on the technology associated with low-field NMR. We present the current state-of-the-art in low-field NMR hardware and experiments, considering general magnet designs, rf performance, data processing and interpretation. We provide guidance on obtaining the optimum results from these instruments, along with an introduction for those new to low-field NMR. The applications of lowfield NMR are now many and diverse. Furthermore, niche applications have spawned unique magnet designs to accommodate the extremes of operating environment or sample geometry. Trying to capture all the applications, methods, and hardware encompassed by low-field NMR would be a daunting task and likely of little interest to researchers or industrialists working in specific subject areas. Instead we discuss only a few applications to highlight uses of the hardware and experiments in an industrial environment. For details on more particular methods and applications, we provide citations to specialized review articles.
Progress in Nuclear Magnetic Resonance Spectroscopy 01/2014; 76:1–60. · 6.02 Impact Factor
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