γ-Al2O3-氧化石墨烯吸附材料用于尿液中核苷的检测

用γ-Al₂O₃纳米粒子键合的氧化石墨烯（GO）作为固相萃取吸附剂，与高效液相色谱法联用，建立了一种对人体尿液中4种核苷分离测定的新方法。采用透射电镜（TEM）、热重分析（TGA）及傅里叶红外光谱（FT-IR）对吸附剂进行表征。考察了洗脱液种类、吸附剂用量、样品体积及样品pH值对吸附性能的影响，通过平衡吸附量衡量吸附效果。在最佳萃取条件下，该吸附剂对核苷具有一定的富集能力。胞苷、肌苷、鸟苷在0.10~10 mg/L，尿苷在0.05~10 mg/L范围内呈现良好的线性关系，线性相关系数为0.9967~0.9973，检出限为0.010~0.021 mg/L，日内和日间相对标准偏差分别为0.1%~0.8%和1.0%~3.1%。实际尿样中，4种核苷的加标回收率为71.3%~107.4%，相对标准偏差（n=3）小于4.8%。该方法灵敏度高、精密度和回收率良好，可用于尿液样品中核苷类物质的富集和测定。

γ-Al2O3-graphene oxide absorbent material for detection of nucleosides in urine

γ-Al₂O₃ nanoparticle-bonded graphene oxide (γ-Al₂O₃-GO) was prepared for use as a solid phase extraction absorbent and for preconcentration of four nucleosides in human urine samples for investigation by high-performance liquid chromatography (HPLC). Transmission electron microscopy (TEM), thermal gravimetric analysis (TGA), and Fourier transform infrared spectroscopy (FT-IR) were employed to characterize the absorbent. Several parameters (eluent species, absorbent amount, sample volume, and sample pH) were optimized, and the absorption efficiency was determined based on equilibrium absorbent amounts. Under optimal conditions, the γ-Al₂O₃-GO absorbent displayed enhanced absorbent ability for nucleosides. The calibration curve showed good linearities in the range of 0.10-10 mg/L for cytidine, inosine, and guanosine, and 0.05-10 mg/L for uridine; the correlation coefficient was observed to be in the range of 0.9967-0.9973. The limits of detection for the four nucleosides were in the range of 0.010-0.021 mg/L. Intra-day and inter-day relative standard deviations were 0.1%-0.8% and 1.0%-3.1%, respectively. The recoveries of the four nucleosides in urine samples ranged from 71.3% to 107.4%, and the relative standard deviations (n=3) were less than 4.8%. The results demonstrated that the proposed method is faster, more sensitive, and more efficient. Therefore, solid phase extraction (SPE)-based γ-Al₂O₃-GO can be considered more suitable for the determination and enrichment of nucleosides in urine samples.