Surface plasmon resonance: Instrumental resolution using photo diode arrays
2000 (English)In: Measurement science and technology, ISSN 0957-0233, Vol. 11, no 11, 1630-1638 p.Article in journal (Refereed) Published
Surface plasmon resonance (SPR) sensors are used to study biomolecular interactions. We have performed a theoretical analysis of a SPR instrument using a convergent beam, a linear detector with various numbers of pixels and various analogue-to-digital converters (ADCs) with a corresponding resolution ranging from 8 to 16 bits. Studies of small molecules at low concentrations or with low affinities are limited by the instrumental set-up, e.g. by the resolution, linearity and noise. The amplitudes of these parameters are highly dependent on the detector, ADC and dip-finding algorithm used. We have studied several dip-finding algorithms, e.g. intensity measurements, second- and third-order polynomial fits and centroid algorithms. Each algorithm used with the ADC and the detector has a resolution associated with it. Some algorithms also have an intrinsic algorithm error that is dependent on the number of pixels and the shape of the dip. A weighted centroid algorithm that has an excellent overall performance is described. If an accuracy of 10-6 refractive index units (RIU) is satisfactory, a 12-bit ADC and a 64-pixel detector are appropriate. Theoretically, by using a 16-bit ADC and a 1024-pixel detector, a resolution of better than 10-9 RIU is obtainable.
Place, publisher, year, edition, pages
2000. Vol. 11, no 11, 1630-1638 p.
Engineering and Technology
IdentifiersURN: urn:nbn:se:liu:diva-47547DOI: 10.1088/0957-0233/11/11/313OAI: oai:DiVA.org:liu-47547DiVA: diva2:268443