Validation of a spectrophotometric methodology for a rapid iodine analysis in algae and seaweed casts

Abstract

Iodine plays an important role in human metabolism and its deficiency is particularly harmful in pregnancy and childhood. It remains a major public health concern in many countries, especially in Portugal. The main purpose of this work was to develop a validated spectrophotometric analysis for a fast and reliable iodine quantification in algal samples. Absorbance was determined at 410 nm demonstrating a good linearity (R 2 ≈ 1.0) in the range of 0-0.06 mg I/100 g. LOD and LOQ were 1.7 × 10 −3 and 5.0 × 10 −3 mg I/100 g, respectively. Accuracy was determined using recovery and varied between 101 and 118%. For precision analysis, an intra-day test performance (RSD = 8.7%) and a repeatability assay (RSD = 3.8%) were performed. Matrix effect assessment demonstrated that this had a negligible effect (3.2%) in the iodine quantification. The spectrophotometric method was externally validated, for iodine quantification in algal samples, by INSA certified laboratory. The correlation coefficient between external iodine quantification and our work was R 2 ≈ 0.9, showing a good correlation. Applicability was assessed in 25 macroalgae species (5 green, 9 red and 11 brown), 12 seaweed casts, collected in Canary Islands and 1 microalga (Isochrysis galbana) provided by ITC (Instituto Tecnologico de Canarias).

A meta-analysis of effects of feeding seaweed on beef and dairy cattle performance and methane yield

“…A. taxiformis was approximately 3 mg/L, and assuming that a child <3 yr old can drink milk at [36]. Further, [37] reported that approximately 31% of ingested iodine is transferred to milk indicating there is potential that when cows are fed dietary supplements of A. taxiformis, iodine concentrations in milk could be substantially greater than those reported by [14].…”

“…In the experiment of [14], the concentration of iodine in milk of cows given 0.5% A. taxiformis was approximately 3 mg/L, and assuming that a child <3 yr old can drink milk at 1 L/d this is approximately 15 times the upper tolerable intake level [35]. Iodine concentrations in A. taxiformis have been reported to range from 8.1 to 11.6 g/kg DM of seaweed [36]. Further, [37] reported that approximately 31% of ingested iodine is transferred to milk indicating there is potential that when cows are fed dietary supplements of A. taxiformis , iodine concentrations in milk could be substantially greater than those reported by [14].…”

Current Status and Future Trends in Removal, Control, and Mitigation of Algae Food Safety Risks for Human Consumption

“…Iodine in algae is volatile and easily reduced or oxidized, so it is challenging to determine the iodine content in seaweed food. The previous study has shown that the spectrophotometric method can quickly and effectively analyze the iodine content in algae samples [ 83 ]. Inductively coupled plasma atomic emission spectrometry (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS) have been used to determine iodine concentrations [ 84 , 85 ].…”

Caracterização química, potencial antioxidante e atividade biológica de macroalgas arribadas do litoral brasileiro

“…Moreover, phlorotannins are polar metabolites rich in the chemical composition of brown macroalgae, commonly found in Z. tournefortii and species from Dictyopteris genus (Murray et al, 2018;Nunes et al, 2019). According to the mechanism of action, these substances can act at different stages of viral infection and can inhibit adsorption, reverse transcriptase and transcription (Ahn et al, 2004).…”

“…According to Nunes et al (2020), this allows the targeting of bioresources for specific purposes, including functional foods. A viable alternative would be to use this biomass for the extraction of biocompounds for industry intents (Nunes et al, 2019).…”