Boron calibration curve

To construct the calibration curve, run 5-50 mL of the standard boron solution by means of a burette into 100 mL graduated flasks, add 30 mL of dilute sulphuric acid, and make up to volume. These solutions contain 1 — 10 /ig of B per 3 mL. Use 3 mL of each solution and of a boron-free comparison solution and proceed as above. Plot a calibration curve relating absorbance and boron content. 

Fig. 2. Spreading resistance profile of four B-doped samples of (100) Si hydrogenated at 122°C. The three higher resistivity samples were hydrogenated for one hour the lowest resistivity sample was treated for four hours. The resistivities were obtained from a calibration curve. Note the greater penetration depth of atomic hydrogen as the boron concentration decreases.

To cite an example, the quantification limit of boron in pure alumina, calculated using a calibration curve covering concentrations from 0 to 4% and measured at 40 kV, 75 mA on a Sc/Mo tube, with a PX3 crystal and a coarse collimator, is 1.3% for an acquisition time of 100 seconds (detection limit 0.4%). 

Figure 7.13 Calibration curves for boron, tungsten and molybdenum from 0.0 to 4.0gg/ml (ppm) using scandium Sc as an internal standard. The units on the Y axis are flask numbers of standards 0.0, 1.0, 2.0, 3.0 4.0 ppm metal respectively...

Read off the appropriate boron concentration from the calibration curve on the basis of the measured extinction, take into account the quantity of... 

From the prepared calibration curve, read off the boron concentration. 

C = concentration of boron from calibration curve in mg/L B d = density of the seawater sample... 

IS. Calibration Curve - The absorbance (A) is plot versus mg/L boron in the standard series. 

Figure 13 Summary of efforts to calibrate 6 B variations in calcite as a function of the pH of precipitation. Results are replotted from Sanyal et al. (1995, 1996, 2000, 2001). The shape of the dashed curves is that predicted by the pH control on the of B(OH)J. The position of these curves was adjusted to fit the O. universa and G. sacculifer data, highlighting the nearly constant boron isotopic offset between these two species of planktonic foraminifera. The upper curve closely approximates the calculated S B of B(OH)jT (see Figure 12). Note that the O. universa and G. sacculifer data plotted include both cultured foraminifera and core-top samples.

---