Rapid automatic detection of water Ca, Mg elements using laser-induced breakdown spectroscopy

Abstract

Ca, Mg, as the main components in water, are not only essential nutrients for life but are also an important index of water hardness. Rapid detection of the element content is of great significance for water quality evaluation and nutrient balance in planting and breeding water. Traditional laboratory analysis methods are time consuming and involve complex procedures. Ion cross sensitivity and response drift also limit the application of online sensors. These disadvantages are not in line with the precise control and rapid response required for practical applications. Here, we propose a rapid automatic Ca, Mg ion concentration detection method using Laser-induced breakdown spectroscopy. Based on a cation exchange membrane, an automatic control system integrating water sampling, hybrid reacting, attachment drying and spectra measuring was constructed. The testing time for one sample could be compressed to 5 min. Consequently, it met the requirements of accuracy and timeliness of water element regulation. The proposed system can provide new technical means for large-scale aquaculture, soilless cultivation of facilities and other scenarios aiming at accurate measurement and control of elements in water body.

Atomic spectrometry update: review of advances in the analysis of clinical and biological materials, foods and beverages

“…The researchers found that it was not possible to make measurements by irradiation of the hydrogel surfaces because of the interference from water. Zhu et al 93 constructed an automated sample preparation and handling device for the LIBS determination of Ca and Mg in water samples (plant and breeding water) in which the analytes were extracted by a cation-exchange membrane (CMI-7000 S from Membrane International Inc. with a thickness of 0.42 mm, an exchange group of SO 3 –Na, exchange capacity 1.6 meq g −1 , and applicable over the pH range 1–14). A 3 cm 2 disc was placed in 20 mL of sample solution, which was stirred by a magnetic follower at 600 rpm for 3 min.…”