Dong-Dong Zhou,Qian Zhang,Hao Zhang,Yin-Zhen Wang,Feng-Qing Yang,Sheng-Peng Wang,Yi-Tao Wang
In this paper, Cu 2+ functionalized Fe 3 O 4 @polydopamine core-shell (Fe 3 O 4 @PDA@Cu 2+ ) magnetic microspheres were prepared by the chelation between Cu 2+ and catechol of polydopamine surface. The synthetic magnetic adsorbent was characterized by Fourier transform infrared spectroscopy , energy dispersive X-ray spectroscopy, vibrating sample magnetometry , thermogravimetric analysis , scanning electron microscope and transmission electron microscopy . Four purines include guanine , adenine , hypoxanthine and xanthine were selected as model compounds to evaluate the applicability of this adsorbent. Several parameters that effected the extraction efficiency, such as extraction time, adsorbent amount, solution pH, ionic strength , eluent type, concentration of eluent and eluent time, were investigated. Under the optimized conditions, good linearity was obtained with correlation coefficients between 0.9983 and 0.9999 for the four analytes, and their LOD and LOQ were 0.42–2.15 ng/mL and 1.41–6.50 ng/mL, respectively. Meanwhile, the RSDs of intra-day and inter-day precision were in the range of 1.43%–5.55% and 4.56%–7.01%, respectively. The spiked recoveries of four purines in real sample were 70.01%–102.42%, indicating this proposed method might have potential applications for the analysis of purines in real samples. In addition, the developed method was used to monitor the concentrations of adenine in rat plasma at different time points after intragastric administration.
Ying Nie,Yuan Luo,Shajie Luo,Xiujun Cao,Guoxin Song,Chunhui Deng
Polystyrene (PS) microsphere is a kind of attractive extracting medium due to its high stability in different matrices and its particle size can be controlled. The attachment of amphiphilic copolymers to the PS microsphere surface can overcome the drawback of PS relevant to its hydrophobic nature and low wettability. In our previous work, the magnetic composite based on PS microsphere (5 µm) and poly (divinylbenzene-co-N-vinylpyrrolidone, DVB-co-NVP) shell was successfully fabricated and applied for the extraction of safrole in cola drinks. However, the large size and ease of sedimentation limited its application in the enrichment of safrole from blood samples. Considering the adjustability of PS microsphere size, we synthesized the porous PS microspheres with the uniform size of 3 µm and then functionalized with Fe 3 O 4 nanoparticles and poly (DVB-co-NVP) layer in this work. Using the proposed material as extraction sorbent, a simple and fast magnetic solid phase extraction (MSPE) method coupled with HPLC was developed for quantification of safrole in the plasma. Under the optimized conditions, the response to safrole was linear in the range of 0.02–12 µg mL −1 , and the limit of detection (LOD) was 0.006 µg mL −1 . Satisfactory recoveries were obtained between 85.67% and 97.74% (spiked at 0.05, 0.2, 2 µg mL −1 ) and the relative standard deviations (RSDs) for the above spiked levels of the analyte were below 3.9% ( n = 6). The adsorbent can be reused for 6 cycles without a significant loss of extraction capability.
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