Coral Ba/Ca Analysis Using ICP‐OES With an Ultrasonic Nebulizer

The barium/calcium ratio (Ba/Ca) in coral skeletons has been used as a proxy to understand river floods and oceanic upwelling in the tropics and subtropics for the past centuries. Here, we establish a new method for Ba/Ca analysis using inductively coupled plasma optical emission spectrometry (ICP‐OES), which has been widely used for coral proxy analyses and can save analysis time compared to other methods. We analyze Ba/Ca by combining an ultrasonic nebulizer with the intensity ratio calibration method to improve the signal intensity of Ba. Our method can determine Ba/Ca in samples with a Ca concentration of 9 mg/L with excellent analytical precision (