毛細管電泳-不均勻電場效應輔助線上掃集法/紫光LED誘導螢光偵測法對尿液中多巴胺及正腎上腺素之分析研究

Abstract

毛細管電泳-不均勻電場效應輔助線上掃集法第一次被提出並且與一般的掃集法在靈敏度上以及分離效果作比較。本實驗選擇的分析物是經由NDA (naphthalene-2,3-dicarboxaldehyde) 螢光標識試劑衍生後的多巴胺以及正腎上腺素。在使用一般的掃集法技術下，當毛細管的進樣長度為30 cm (大約佔毛細管總長的1/3) 時，此時的分離度僅有1.5；然而當使用不均勻電場效應輔助線上掃集法時，分離度可以很明顯的增加到9.2。另外在偵測靈敏度上，以紫光/發光二極體 (發光功率大約2mW) 為螢光激發光源時，對於多巴胺衍生物其偵測極限大約是10-9 M，與使用一般的掃集法的偵測極限相近，因為此時的進樣量是相同的。除此之外，這個技術對於偵測尿液中低濃度的多巴胺也提供了足夠的靈敏度以及分離效果。

An unequal electric field assisted sweeping-MEKC (UEFA/sweeping-MEKC) technique is proposed, for the first time, and compared to the normal sweeping-MEKC with reference to sensitivity and separation efficiency. NDA (naphthalene-2,3-dicarboxaldehyde) derivatized-dopamine and -norepinephrine, were selected for use as model compounds. In the case of normal sweeping-MEKC, the findings show that, when a portion (30 cm, ~1/3 of the total length of the capillary) of sample matrix was injected into the capillary, the separation resolution was only 1.5. However, this was dramatically improved to 9.2 when the UEFA/sweeping-MEKC technique was applied. In the view of sensitivity, when a violet-LED (~ 2mW) was used as the fluorescence excitation source, the limit of detection for NDA-labeled dopamine was determined to ~10-9 M, the similar to that for normal sweeping-MEKC, since the injected sample volume is same. In addition, this method also provides sufficient sensitivity and separation efficiency for the detection of low concentrations of dopamine in urine.