5 × 10-4 mol/L CdTe (referring to Cd2+), which might be caused by a much higher concentration of CdTe NCs and generated more luminophor. In order to get a higher sensitivity, the concentration of 2.5 × 10-4 mol/L was recommended in this assay. Figure 6 Effect of CdTe NC concentration. Effect of hydrogen this website peroxide concentration The concentration of hydrogen peroxide (H2O2) was optimized in the range of 0.1 ~ 1.1 mol/L in a FIA-CL mode described in the experimental section. As shown in Figure  7, the CL intensity continued to increase with the increase of H2O2 concentration up to 1.0 mol/L, then decreased. In order to get larger CL response signal and lower background signal,

the concentrate of H2O2 1.0 mol/L was used in the work. Figure 7 Effect of H 2 O 2 concentration. Effect of sodium hypochlorite concentration The effect of NaClO concentration on CL emission was investigated in the range Selleckchem Volasertib of 0 ~ 2.54 × 10-1 mol/L (Figure  8), and the CL intensity increased as the NaClO concentration increased from 0 up to 1.27 × 10-2 mol/L. However, when the NaClO concentration was more than 1.27 × 10-2 mol/L, the CL intensity decreased instead. Therefore, the optimum NaClO concentration, 1.27 × 10-2 mol/L, was adopted. Figure

8 Effect of sodium hypochlorite (NaClO) concentration. At a lower concentration of NaClO or H2O2, the signal increases gradually, and the maximum CL intensity occurs at a concentration.

Over this concentration, poor relative CL intensity was observed. This may be caused by the increasing CBL-0137 of solution viscosity and self-decomposition at high concentration [21, 33]. Effect of pH value It was investigated that the CL signal was stronger under the alkaline condition. Cyclooxygenase (COX) The effect of pH buffer solution of NaHCO3-Na2CO3 on CL intensity were investigated in the pH values of 9.47, 9.73, 9.90, 10.08, 10.35, 10.77, and 11.54. The results demonstrated that CL intensity increased with the increase of pH value (Figure  9). The CL intensity achieved its maximum at 11.54. So, NaHCO3-Na2CO3 buffer solution of pH = 11.54 was chosen in the system. Figure 9 Effect of pH. Determination of estrogens Under the optimized experimental conditions, the calibration graph of the estrogens showed that the relative CL intensity (I) was linearly proportional to the logarithm of the concentration of the estrogen standard solution (C). The linear ranges, regression equations, correlation coefficients (R), and detection limits obtained were summarized in Table  1. The linear ranges of the determination on estrogens were 3.0 × 10-6 ~ 1.0 × 10-4 mol/L, 1.0 × 10-6 ~ 1.0 × 10-4 mol/L, and 1.0 × 10-6 ~ 7.0 × 10-5 mol/L for estrone, estradiol, and estriol, respectively. And the detection limits were 1.3 × 10-7, 3.1 × 10-7, and 1.6 × 10-7 mol/L for estrone, estradiol, and estriol, respectively.