提出了基于微流控纸芯片-显色法快速测定全血中尿酸含量的方法。使用喷蜡打印机将设计的微通道网格打印在色谱纸上,经过加热处理得到微流控纸芯片。在微流控纸芯片I区(样品预处理区)滴加3.2 μL 0.10 g·mL^-1乙二胺四乙酸(EDTA)溶液和4.8 μL 0.015 g·mL^-1壳聚糖溶液,干燥,得到微流控纸芯片检测平台。全血样品与磷酸盐缓冲液(pH 7.4)按体积比1∶4混合,分取混合溶液13 μL滴加至I区,红细胞与血浆在壳聚糖和EDTA的凝集作用下发生分离,血浆流动至II区(显色区);待血浆完全铺满II区后,滴加3 μL三氯化铁和邻二氮菲的混合溶液,静置反应2 min,用手机拍照,采用Photoshop CS2软件分析显色区的颜色强度,得到RGB值(红、绿、蓝三色叠加值),根据标准曲线计算尿酸含量。结果表明:全血中葡萄糖等常见还原性物质均不影响尿酸含量的测定;尿酸浓度在0.05~0.85 mmol·L^-1内与RGB值呈线性关系,检出限(3.3s/k)为0.03 mmol·L^-1。方法用于实际全血样品分析,并与某医院检验科的测定结果进行比对,结果显示该方法所测结果与医院检测结果无显著性差异;按照标准加入法对实际样品进行回收试验,回收率为103%~110%。

A method for the rapid determination of uric acid in whole blood by colorimetric method based on microfluidic paper chip was proposed. The designed microchannel grid was printed on chromatographic paper by wax jet printer, and the microfluidic paper chip was obtained after heat treatment. To prepare the microfluidic paper chip detection platform, 3.2 μL of 0.10 g·mL^-1 ethylenediamine tetraacetic acid (EDTA) solution and 4.8 μL of 0.015 g·mL^-1 chitosan solution were added onto zone I (sample pretreatment zone), and the chip was dried. The whole blood sample and phosphate buffer solution (pH 7.4) were mixed at volume ratio of 1∶4, and an aliquot of the mixture (13 μL) was added onto zone I. Red blood cells and plasma were separated by the agglutination of chitosan and EDTA, and plasma flowed to zone II (coloration zone). After plasma completely covered zone II, 3 μL of the mixed solution of ferric trichloride and o-diazophene was added for settling reaction for 2 min. Photo was taken by a mobile phone, and Photoshop CS2 software was employed to analyze the color intensity of the coloration zone, and then RGB value (representing the superposition value of red, green and blue) was obtained to calculate the uric acid content based on the standard curve. It was shown that common reducing substances in whole blood, such as glucose, did not interfere with the determination of uric acid. Linear relationship between the concentration of uric acid and RGB value was kept in the range of 0.05-0.85 mmol·L^-1, with detection limit (3.3s/k) of 0.03 mmol·L^-1. The method was used to analyze actual whole blood samples and compared the determined results from a clinical laboratory of hospital. It was shown that there was no significant difference between the determined results of the method and the hospital. Test for recovery by standard addition method on the actual sample, giving results in the range of 103%-110%.