Mass-produced lonophore-based fluorescent microspheres for trace level determination of lead ions.
Mass-produced lonophore-based fluorescent microspheres for trace level determination of lead ions.
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DOI：
10.1021/ac025596i
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发表时间：
2002-09
影响因子：
7.4
通讯作者：
M. Telting-Diaz;E. Bakker
中科院分区：
文献类型：
--
作者：
M. Telting-Diaz;E. Bakker
本文报道了用于快速痕量铅离子分析的小而均匀、大批量生产的增塑PVC基传感微球的研制和表征。通过自动浇铸工艺获得的微米级颗粒通过以类似于传统光极传感膜的方式用高度选择性的组分掺杂它们而呈现对铅离子的选择性。含有亲脂性离子载体N，N，N '，N'-四十二烷基-3-6-二氧杂辛烷-1-硫代-8-氧代二酰胺的单个颗粒（ETH 5493）、色离子载体ETH 5418连同亲脂性吲哚羰花青衍生物作为内参比染料（DiIC 18）和亲脂性离子交换位点四[3，5-双三氟甲基苯基]硼酸钠，在pH缓冲溶液中的低纳摩尔水平下产生可测量的铅响应。在pH 5.7时，单个颗粒的检测限为3 x 10（-9）M。通过在流动的水相中可再现地形成聚合物液滴，然后收集尺寸约为13微米的球形颗粒来制造微球。将颗粒固定化并通过荧光显微镜在微流池中单独测定。发现的选择性模式与先前报道的铅选择性配体ETH 5493一致，并且所有响应函数都完全由理论描述。与在分析物的稀释样品中需要非常长的平衡时间和大的样品体积的光极膜相比，颗粒表现出极大增强的平衡响应时间。因此，对于铅样品浓度在5 × 10（-8）M及以上，响应时间约为3分钟，而在检测限，完全平衡记录后仅15分钟，所需的样品体积的数量级为1毫升。这类新的微球似乎是适合于快速和灵敏的离子检测在痕量水平的环境和生物应用。
The development and characterization of small, uniform, and mass-produced plasticized PVC-based sensing microspheres in view of rapid trace level analysis of lead ions is reported. Micrometer-sized particles obtained via an automated casting process were rendered selective for lead ions by doping them with highly selective components in a manner analogous to traditional optode sensing films. Single particles that contained the lipophilic ionophore N,N,N',N'-tetradodecyl-3-6-dioxaoctane-1-thio-8-oxodiamide (ETH 5493), the chromoionophore ETH 5418 together with a lipophilized indocarbocyanine derivative as internal reference dye (DiIC18), and lipophilic ion-exchanger sites sodium tetrakis[3,5-bistrifluoromethylphenyl]borate, yielded measurable lead responses at the low nanomolar level in pH buffered solutions. The detection limit for single particles was 3 x 10(-9) M at pH 5.7. The microspheres were fabricated via a reproducible formation of polymer droplets within a flowing aqueous phase followed by collection of spherical particles of approximately 13 microm in size. The particles were immobilized and assayed individually in a microflow cell via fluorescence microscopy. Selectivity patterns found were in agreement with those reported earlier for the lead-selective ligand ETH 5493, and all response functions were fully described by theory. In contrast to optode films that necessitated very long equilibration times and large sample volumes in diluted samples of analyte, particles exhibited extremely enhanced equilibrium response times. Thus, for lead sample concentrations at and above 5 x 10(-8) M, response times were approximately 3 min, whereas at the detection limit, complete equilibrium was recorded after just 15 min, with required sample volumes on the order of 1 mL This new class of microspheres appears to be suitable for rapid and sensitive ion detection at trace levels in environmental and biological applications.