کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
9748612 1493786 2005 10 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Expanded electrical model of a contactless conductivity detector: Development and verification
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی آنالیزی یا شیمی تجزیه
پیش نمایش صفحه اول مقاله
Expanded electrical model of a contactless conductivity detector: Development and verification
چکیده انگلیسی
A theoretical model of the contactless conductivity detector (CCD) has been developed consisting of a network of resistors and capacitors. The output of the model is compared to experimental results and to the output of a simpler model. Experimentally, a lock-in amplifier is added to the detection scheme of the contactless conductivity detector to provide a more sensitive method of signal isolation. The detector is assembled on a printed circuit board with the electrodes in a co-axial configuration. The electrodes are chosen to allow for use with fused silica capillaries in capillary electrophoresis. The use of a lock-in amplifier in place of a previous rectification/filtering circuit allows for an approximate 10-fold improvement in S/N. The detector shows a linear response to changes in excitation voltage and to changes in analyte concentration. Mass limits of detection of 60, 63, and 50 fg are determined for the inorganic cations potassium, sodium, and lithium, respectively (for a signal three times the level of the rms noise).
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Chromatography A - Volume 1094, Issues 1–2, 11 November 2005, Pages 148-157
نویسندگان
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