Duffy G, Maguire I, Heery Brendan, Gers Pauline, Ducrée J, Regan F
Water Institute, School of Chemical Sciences, Dublin City University, Dublin 9, Ireland.
School of Physical Sciences, Fraunhofer Project Centre at Dublin City University (FPC@DCU), Glasnevin, Dublin 9, Ireland.
Talanta. 2018 Feb 1;178:392-399. doi: 10.1016/j.talanta.2017.09.066. Epub 2017 Sep 23.
The development of a centrifugal device for quantitative analysis of both chromium (III) and (VI) species in water is reported. ChromiSense is a colourimetric sensor system that has been applied to the measurement of chromium in spiked river water samples. For analysis, the sample is loaded into a reservoir on the disposable microfluidic disc, along with reagents. A centrifugal force is created by spinning the disc to pump liquids through microchannels, causing them to mix and react to form a coloured product. The coloured product is then presented to a low-cost optical detection system, where absorbance measurements can be recorded. The optical detection system consists of a light emitting diode (LED) and photodiode (PD) couple. Chromium (III) was measured using 2,6-pyridine dicarboxylic acid as a ligand, forming a complex that was measured at 535nm and at 335nm. While measuring at 535nm allowed for the use of a low cost LED, the sensitivity was improved 2.5 times by measuring at 335nm. However, 335nm also yielded a diminished linear range with little improvement in limit of deteciton (LOD), and required a lengthier manufacturing process due to the need for a UV-transparent material. Chromium (VI) was detected using 1,5-diphenyl carbazide (DPC). This standard analysis method was simplified for automation on-disc, and optimised to achieve a low LOD. The LOD for trivalent and hexavalent chromium using this device were 21mgL and 4μgL, respectively. The linear range for quantitative analysis was found to be 69-1000mgL for Cr(III) and 14-1000μgL for Cr (VI). While this range is high for Cr(III), incorporation of an off-disc pre-concentration method would make this technology suitable for environmental sample analysis. The device is simple to use, low in cost, and could provide rapid on-site measurements, with results comparable to those obtained using a benchtop spectrophotometer.
报道了一种用于定量分析水中铬（III）和铬（VI）的离心装置的开发。ChromiSense是一种比色传感器系统，已应用于加标河水样品中铬的测量。分析时，将样品与试剂一起加载到一次性微流控盘上的储液器中。通过旋转圆盘产生离心力，以泵送液体通过微通道，使它们混合并反应形成有色产物。然后将有色产物呈现给低成本的光学检测系统，在该系统中可以记录吸光度测量值。光学检测系统由发光二极管（LED）和光电二极管（PD）对组成。使用2,6-吡啶二甲酸作为配体测量铬（III），形成在535nm和335nm处测量的络合物。虽然在535nm处测量允许使用低成本的LED，但在335nm处测量可将灵敏度提高2.5倍。然而，335nm处的线性范围也减小了，检测限（LOD）几乎没有改善，并且由于需要紫外线透明材料，制造过程更长。使用1,5-二苯基卡巴肼（DPC）检测铬（VI）。这种标准分析方法被简化以实现盘上自动化，并进行了优化以实现低检测限。使用该装置时，三价铬和六价铬的检测限分别为21mg/L和4μg/L。发现定量分析的线性范围对于Cr（III）为69-1000mg/L，对于Cr（VI）为14-1000μg/L。虽然这个范围对于Cr（III）来说很高，但采用盘外预浓缩方法将使该技术适用于环境样品分析。该装置使用简单，成本低，可以提供快速的现场测量，结果与使用台式分光光度计获得的结果相当。
