Determination of nutrients in sugarcane juice using slurry sampling and detection by ICP OES

The fractional factorial and Doehlert designs for optimization of a slurry sampling procedure to determine of nutrients in sugarcane juice by inductively coupled plasma optical emission spectrometry (ICP OES) were applied. External calibration curves were used for direct analysis of the slurry. This procedure allowed determination of Ca, Cu, Fe, K and Mg with limits of detection (LoD) obtained of 2.0, 0.04, 0.2, 1.0 and 1.5 mg L−1, respectively. The precision was expressed as relative standard deviation (%RSD), being better than 1.4% (n = 3). Accuracy was confirmed by comparison with sample digestion method. The results for analysis of fourteen sugarcane juices samples demonstrated that the nutrients Ca, Cu, Fe, K and Mg have average contents of 108, 0.506, 6.40, 470 and 114 mg L−1, respectively. The proposed analytical method is a good alternative for simultaneous determination of nutrients in sugarcane juice using introduction of slurries and detection by ICP OES.