Mineral and Trace Metal Concentrations in Seaweeds by Microwave-Assisted Digestion Method Followed by Quadrupole Inductively Coupled Plasma Mass Spectrometry Suman Thodhal Yoganandham 1 & Vasantharaja Raguraman 1 & GobalaKrishnan Muniswamy 1 & Gayathri Sathyamoorthy 1 & Remya Rajan Renuka 1 & Jayaseelan Chidambaram 1 & Thirugnanasambandam Rajendran 1 & Kumar Chandrasekaran 1 & Radhika Rajasree Santha Ravindranath 1 Received: 7 April 2018 /Accepted: 24 May 2018 # Springer Science+Business Media, LLC, part of Springer Nature 2018 Abstract This study reports the total concentrations of mineral and trace metals sodium, potassium, calcium, magnesium, phosphorus, iron, copper, zinc, and manganese in the seaweeds Padina tetrastromatica, Turbinaria ornate, Sargassum wightii, Sargassum swartzii, Gracilaria edulis, Ulva lactuca, Chaetomorpha antennina, and Halimeda opuntia collected from mandapam coastal regions, Southeast coast of India. Microwave-assisted digestion was used for sample preparation prior to mineral and trace metal analysis. Mineral and trace metal analyses were determined by inductively coupled plasma mass spectrometry. The ranges of concentra- tions of mineral and trace metals in algae were 27.04 ± 2.54–194.08 ± 2.36 mg/kg for manganese, 1.88 ± 0.10–121.5 ± 0.70 mg/ kg for sodium, 6.5 ± 0.56–90.5 ± 2.12 mg/kg for magnesium, 59.07 ± 0.34–672 ± 2.82 mg/kg for potassium, 13.15 ± 2.08– 135.13 ± 1.59 for sulfur, 0.003 ± 0.001–3.44 ± 0.13 mg/kg for cobalt, 0.39 ± 0.19–8.95 ± 0.38 mg/kg for copper, 0.72 ± 0.28– 25.72 ± 0.39 mg/kg for zinc, and 6.01 ± 0.27–188.47 ± 1.92 mg/kg for iron.The results were evaluated statistically, and the significant difference was observed in the mean concentrations of all mineral and trace elements, except Co, Cu, and Zn, among the type of seaweeds. Keywords Inductively coupled plasma mass spectrometry . Microwave-assisted digestion . Seaweeds . Mineral . Trace metals . Multielement Introduction Seaweeds are macro algae that grow in rocky landscape or on coral reefs or can grow at great depths if sunlight can penetrate through the water [1]. Most of the seaweeds can be seen thriv- ing in underwater beds floating along the sea surface attached to rocks [2]. According to previous report, 221 seaweed spe- cies (125 red (Rhodophyta), 32 green (Chlorophyta), and 64 brown (Phaeophyta) seaweeds) are being used as fertilizer, food fodder, medicine, and now used in industry for the pro- ductions like carrageenan, algin, and agar [3]. Seaweeds are easily cultivated and achieve rapid growth for several species [4]. Seaweeds are traditionally consumed by humans as part of daily diet in Asian countries mainly Japan, Korea, and China. Seaweed contains rich sources of minerals; sometimes, their content is as high as 40% [5, 6]. This is because seaweeds accumulate metal ions from salt water and concentrate those substances as carbonate salts in their fronds [7]. Generally, seaweeds constitute in polysaccharides, minerals, vitamins, and other bioactive substances like proteins, polysaccharides, polyphenols, and lipids with antifungal, antibacterial, and an- tiviral properties [8, 9]. The most common minerals found in seaweeds are phosphorus, potassium, iodine, sodium, magne- sium, calcium, iron, copper, and fluorine [10]. The seaweeds show great variation in the mineral content based on environ- mental factors as water temperature, salinity, light, and nutri- ents [11]. To fully exploit the nutritional value of seaweeds, several studies conducted on nutritional values and biochem- ical composition of various seaweeds collected from different parts of the world have been conducted [12–16]. Compared to land plants, the chemical composition of seaweeds has been poorly investigated. * Suman Thodhal Yoganandham sumancas2010@gmail.com 1 Ecotoxicology Division, Centre for Ocean Research, Col. Dr. Jeppiar Research Park, Sathyabama Institute of Science and Technology, Chennai, India Biological Trace Element Research https://doi.org/10.1007/s12011-018-1397-8