新型Ca^(2+)指示剂STDIn双波长比率法测定血清钙

Dual-wavelength ratiometric determination of free-calcium with new Ca^2+ indicator STDIn

采用自行设计合成的新型Ca2+指示剂STDIn,建立了一种可在生理条件下测定血清中Ca2+的新方法.指示剂STDIn在pH值为7.2的中性缓冲介质中,可与Ca2+络合形成稳定的络合物,试剂自身的吸收峰位于543nm,与Ca2+络合后紫移至423nm,Δλ=120nm,对比明显.在指示剂浓度为10μmol/L时,采用双波长比率法求得测定Ca2+的线性范围分别为2×10-5～2×10-3mol/L(相关系数r=0.9977)和5×10-3～1×10-1mol/L(相关系数r=0.9968),检出限为6×10-6.该法已用于血清中Ca2+的测定.

A novel method for the determination of free-calcium in serum under physiology condition is established by indicator STDIn that is synthesized. The indictor STDIn reacts with calcium to form a stable complex in pH 7.2 buffer solution. The maximum absorption wavelength (λ_max) of the complex is 423 nm, that of the indicator STDIn is 543 nm. The peak of complex has a 'violet shift' of 120 nm as compared with that of the reagent. The liner curve with dual-wavelength ratiometric determination is in the range of 2×10^-5～2×10^-3 mol/L (r=0.997 7) and 5×10^-3～1×10^-1 mol/L(r=0.996 8). The detection limit is 6×10^-6.The method has been applied to the determination of free-calcium in serum sample with satisfactory results.