Specificity and Sensitivity of Fluorescence Labeling of Surface Species
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- 作者：Yangjun Xing ; Eric Borguet
- 刊名：Langmuir
- 出版年：2007
- 出版时间：January 16, 2007
- 年：2007
- 卷：23
- 期：2
- 页码：684 - 688
- 全文大小：280K
- 年卷期：v.23,no.2(January 16, 2007)
- ISSN：1520-5827
文摘
FLOSS (fluorescence labeling of surface species) enables one to identify and quantify very low concentrations ofsurface functional groups. Unlike most surface analytical techniques, FLOSS can provide absolute, as well as relative,surface coverage determination. However, as with any other surface derivatization technique, FLOSS provides a lowerlimit to surface coverage. The specificity of FLOSS for a particular functional group is the key to this application.In one FLOSS protocol, amine-modified dyes are used to label surface aldehyde groups. However, amine-modifieddyes, in principle, can bind to both aldehyde and carboxyl groups, limiting specificity. In this paper, we report thatthe FLOSS protocol devised results in less than 0.5 % of the carboxyl-modified dyes binding to the surface aminegroups. Therefore, the presence of carboxyl groups on the surface should have a limited effect on the detection ofaldehyde groups by amine-modified dye. Quenching of fluorescence can potentially affect quantitative measurements.To address this issue, the densities of surface functional groups of CHO-, NH2-, and epoxy-coated glass surfaces werequantified using FLOSS and compared to surface densities estimated by other methods. The FLOSS technique wasextended to glass surfaces by using visible absorbing and emitting dyes. The lower detection limit is on the orderof 109groups/cm2.