Coconut water is not only a natural drink for hydration, but also contains different minerals that help regulating the body fluid balance. In this application, minerals (Na⁺, K⁺, Mg²⁺, and Ca²⁺) in coconut water were quantified. A simple sample pretreatment requires only diluting a commercial coconut water 1+19 with ultra-pure water and filtering the mixture using a 0.45-µm membrane filter.

Sample: 10 μL each
(Sample soltion) 20-fold diluted Coconut water with H₂O

1. 2.Na⁺
2. 4.K⁺
3. 5.Mg²⁺
4. 6.Ca²⁺

(Standard solution) 0.5 % each

1. 1.Li⁺ 2 mg/L
2. 2.Na⁺ 10 mg/L
3. 3.NH₄⁺ 10 mg/L
4. 4.K⁺ 20 mg/L
5. 5.Mg²⁺ 10 mg/L
6. 6.Ca²⁺ 20 mg/L