Fig. 4From: Fast and simple selenium speciation by solid phase extraction and laser-induced breakdown spectroscopyCalibration curve of Se (VI) from LIBS analysis of the membrane filters. The filled squares represent the experimental values, and the red line is a linear fit of them (y = a + bx, with a = − 6.85 ± 5.05, b = 10.55 ± 0.06, and R2 = 0.9983)Back to article page