Fenton Digestion of Milk for Iodinalysis

Abstract

Iodine is an essential micronutrient especially important in the neurodevelopment of infants. Spot samples of urinary iodine (UI) are used as an epidemiologic index of adult iodine nutrition. Individual infant iodine nutrition is of vital importance, but infant urine is difficult to collect, much less a 24 h sample. Monitoring the intake provides a pragmatic solution for determining infant iodine nutrition. Because of the high solids content of milk and the possible existence of iodine in an organically bound form, sample digestion is obligatory. The U.S. Food and Drug Administration, for example, uses wet ashing by HClO(4); special precautions and fume hoods are required. We present a method of Fenton digestion of human and bovine milk samples and infant formula. No specialized equipment or hazardous reagents are used; measurement is made by isotope dilution inductively coupled plasma mass spectrometry. In Fenton digestion, Fe(II) and H(2)O(2) oxidizes the sample. In an interlaboratory study, excellent agreement (r(2) = 0.9934) was observed with results obtained by HClO(4) digestion and Sandel-Kolthoff kinetic colorimetry. Average recoveries of iodide, triiodothyronine, and thyroxine ranged between 100% and 101%. Following digestion, iodine was found to exist entirely as iodide. Control of pH is imperative if loss cannot be corrected for by isotope dilution. Loss was below 20% for all samples when the pH was between 2.25 and 2.5.

Analytical Method for the Determination of Trace Toxic Elements in Milk Based on Combining Fe3O4 Nanoparticles Accelerated UV Fenton-like Digestion and Solid Phase Extraction

“…On the basis of the observations from previous studies [24][25][26]39 and the above study, the reaction mechanism may consist of a dominant digestion and a subsidiary digestion, which have occurred on the surface of MNPs and in the leaching solution, respectively. Figure 1A,B shows that the mixture can be digested to some extent in the 30,80, and 120 nm were tested to digest the milk mixture under the same experimental conditions, as shown in Figure 2. Interestingly, catalytic activity of Fe 3 O 4 MNPs was clearly decreased with increasing of its particle diameter, and the milk solution can be completely digested within 60 min using MNPs with 30 nm diameters, while a much longer time was required in the case of MNPs with 80 or 120 nm diameters.…”

Novel Pretreatments of Whole Blood Using Fenton-Like Processes for Trace Metal Analysis

“…The pH must stay below 7 during the process. Otherwise the iron catalyst will precipitate as FeO(OH) (Shelor et al 2011). …”

Iodine: An Essential Trace Element

“…Iodine is an essential element for the human being because it is part of the thyroid hormones ( Figure 1) [16]. A deficient iodine intake can cause serious problems such as hypothyroidism, cretinism, among others [3]. For this reason, various organizations such as the American institution "Institute of Medicine" or the European Food Safety Agency have set guide values for recommended daily intake of iodine, being 150 μg/day for adults [4,5].…”

“…Iodine is an essential trace element for humans [2]. This element is necessary because it is part of the hormones of the thyroid [3]. Iodine deficiency in the body can lead to serious problems such as hypothyroidism, cretinism, goiter, etc [3].…”

“…This element is necessary because it is part of the hormones of the thyroid [3]. Iodine deficiency in the body can lead to serious problems such as hypothyroidism, cretinism, goiter, etc [3]. The EFSA (European Food Safety Authority) has set a recommended daily intake (RDI) of 150 μg/day for adults [4].…”