School of Physical Sciences and Australian Centre for Research on Separation Science (ACROSS), University of Tasmania , Hobart 7001, Australia.
Centre for Food Innovation, University of Tasmania , Locked Bag 1370, Launceston 7250, Australia.
Anal Chem. 2016 Dec 20;88(24):12116-12121. doi: 10.1021/acs.analchem.6b02832. Epub 2016 Sep 26.
In this work, for the first time, a sub-250 nm light-emitting diode (LED) is investigated as a light source for optical detection in chemical analysis. A 235 nm deep ultraviolet-light-emitting diode (UV-LED) is employed within an on-capillary photometric detector and applied in capillary ion-exchange chromatography (IEC) for the detection of common ultraviolet (UV)-absorbing anions (here, iodide, nitrate, and nitrite). This investigation focused on fundamental properties of UV-LEDs, in particular, emission spectra, radiometric power, effective heat dissipation with a passive heat sink, and energy conversion. The detection showed excellent linearity with stray light down to 0.6%, and an effective path length at 92% of the used capillary inner diameter. The analytical performance parameters were demonstrated by detection of chromatographic separation of iodide in simulated seawater, showing a limit of detection (LOD) of 1.30 μmol L, a linear range of 7.9-3937 μmol L, and reproducibility (with a relative standard deviation (RSD)) of 0.6% for peak height 0.7% for peak area. In addition, nitrite and nitrate were selected to study the potential of using deep UV-LEDs as the light source in photometric detection for even lower-wavelength-absorbing analytes (λ = 209 nm for nitrite and 200 nm for nitrate), showing reproducibility (RSD = 1.2% and 3.6% for peak height and 0.9% and 2.9% for peak area, respectively) and LOD = 7 and 26 μmol L.
在这项工作中，首次研究了亚 250nm 发光二极管（LED）作为光化学分析中光学检测光源。在毛细管光电检测器内使用 235nm 深紫外发光二极管（UV-LED），并将其应用于毛细管离子交换色谱（IEC）中，用于检测常见的紫外（UV）吸收阴离子（此处为碘化物、硝酸盐和亚硝酸盐）。该研究重点关注 UV-LED 的基本特性，特别是发射光谱、辐射功率、无源散热器的有效散热以及能量转换。检测结果表明，与杂散光（低至 0.6%）和有效光路长度（达到所用毛细管内径的 92%）达到了极好的线性关系。通过检测模拟海水中碘化物的色谱分离，展示了分析性能参数，检测限（LOD）为 1.30 μmol L，线性范围为 7.9-3937 μmol L，峰高的重现性（相对标准偏差（RSD））为 0.6%，峰面积的重现性为 0.7%。此外，还选择了亚硝酸盐和硝酸盐来研究深紫外 LED 作为光度检测光源，用于检测甚至更低波长吸收分析物（亚硝酸盐的 λ=209nm，硝酸盐的 λ=200nm）的潜力，显示出重现性（峰高的 RSD 分别为 1.2%和 3.6%，峰面积的 RSD 分别为 0.9%和 2.9%）和 LOD=7 和 26 μmol L。
