Dear Sir. Concerning your issue about the best buffer to run the Triiodothyronine hormone in SPR machine . An apparatus and method for high throughput surface plasmon resonance (SPR) sensor subarray comprising two or more SPR sensor subarrays having a target layer on an SPR layer, wherein the SPR sensor subarrays are exposed to a solution until a baseline measurement is attained, is disclosed. Once the SPR sensor subarrays have attained baseline, the SPR sensor subarrays are used to determine the interaction properties between said SPR sensor subarray and a test entity. Binding of 4-carboxybenzene-sulfonamide to carbonic anhydrase II (CA-II), monitored on a surface of covalently immobilized CA-II, for various concentrations of 4-carboxybenzene-sulfonamide (2-fold dilution series from 100 nM – 25.6 µM) at 25 ˚C in PBS, pH 7.4 (10 mM H2NaPO4; 150 mM NaCl); 0.3 % DMSO, at 50 µl/s. CA-II was immobilized at 3,829 RU using standard amine coupling chemistry. The apparent on- and off-rate constants were by globally fit (black) to a 1:1 kinetic binding model (with mass transport considerations) to the sensorgrams using the software supplied with the instrument. Highlighted inset shows plot of the steady-state response (measured from the region of the sensorgram indicated by the box) versus the concentration of analyte and the determined affinity constant. I think the following below links may help you in your analysis:

http://ctcb.bio.ed.ac.uk/CTCB/SPR_-_Surface_Generation_and_Results.html

https://www.google.ch/patents/US6111652

Thanks

Triiodothyronine is soluble in base, dissolve it at 1mg/mL into 1.0M NaOH and then dilute it into PBS buffer (see link). 

http://www.sigmaaldrich.com/content/dam/sigma-aldrich/docs/Sigma/Product_Information_Sheet/1/t2877pis.pdf

Thanks Dears.

Dear Sir Bruce Levison still I am facing problems regarding the preparation of sample solution  of T3 in PBS buffer with pH 7.4, when I dissolved the T3 in 0.1M NaOH and then added in prepared PBS of 7.4 pH solution the pH of the solution were increases then I added the one droop of HCl the pH decreases while at 7.4 which is the required pH the template become insoluble in the buffer solution.

Does I run the sample solution of higher pH through SPR?

What actually the role of buffer in SPR machine?