Determination of the Nutrient and Toxic Element Content of Wild-Collected and Cultivated Seaweeds from Hawai'i.

For centuries, Hawaiians have gathered seaweed for food, medicine, and ceremonial purposes. Seaweed contains nutrients, but some varieties can accumulate toxic elements. We measured target macrominerals (Na, Mg, P, K, Ca), microminerals (B, V, Mn, Co, Cu, Zn, Mo), and nonessential/toxic elements (As, Sr, Cd, Sn, Hg, Pb, and U) in a sample of wild-collected and cultivated seaweeds from Hawai'i.

Distribution of 26 major and trace elements in edible seaweeds from the US market.

In this study we present an elemental profile of 46 edible seaweed samples purchased in the United States. The seaweeds were grouped in 13 subgroups/species based on DNA barcoding analysis. The seaweeds were decomposed by microwave accelerated acid digestion followed by quantification of 26 elements by ICP-MS.

Suitability of DNA Sequencing Tools for Identifying Edible Seaweeds Sold in the United States.

Seaweeds have been consumed by billions of people around the world and are increasingly popular in United States (US) diets. Some seaweed species have been associated with adverse health effects-such as heavy metal toxicity-and higher priced seaweeds may be more prone to adulteration. Knowing which species of seaweeds are being marketed in the US is important for protecting human health and preventing economic adulteration.

Market Basket Survey of Arsenic Species in the Top Ten Most Consumed Seafoods in the United States.

The study focused on the determination of arsenic species in the top ten most consumed seafoods in the United States. Fifty-four samples were collected from local supermarkets, and their species identities were confirmed by DNA barcoding. The total arsenic in the samples varied greatly in the range of 8-22200 ng/g (wet mass).

Matrix-induced transformation of arsenic species in seafoods.

The paper presents a study on the matrix-induced transformation of arsenic (As) species spiked into seafoods. Sixteen arsenicals were individually spiked into samples of finfish, crustaceans and molluscs. The spiked samples were subjected to hot water extraction at 90 °C, and extracts were analyzed by high pressure liquid chromatography (HPLC) interfaced with inductively coupled plasma mass spectrometry (ICP-MS).

Quantitative Determination of Arsenic Species from Fruit Juices Using Acidic Extraction with HPLC-ICPMS.

Throughout the US Food and Drug Administration's routine monitoring of various juice samples for elemental contaminants, a limited number of samples exhibited unexpected behavior related to the arsenic content. Juice samples were subjected to total arsenic determination and those containing arsenic > 10 μg kg were subjected to arsenic speciation analysis using FDA Elemental Analysis Manual (EAM) 4.10 method (AOAC First Action Method 2016.

Speciation analysis of arsenic in seafood and seaweed: Part II-single laboratory validation of method.

Single laboratory validation of a method for arsenic speciation analysis in seafood and seaweed is presented. The method is based on stepwise extraction of water-soluble and non-polar arsenic with hot water and a mixture of dichloromethane and methanol, respectively. While the water-soluble arsenicals were speciated by anion and cation exchange liquid chromatography inductively coupled plasma mass spectrometry (LC-ICP-MS), the non-polar arsenicals were collectively determined by ICP-MS after digestion in acid.

Speciation analysis of arsenic in seafood and seaweed: Part I-evaluation and optimization of methods.

Several extraction and chromatographic methods were evaluated to identify optimum conditions for arsenic speciation analysis in seafood and seaweed. The extraction systems, which include aqueous, aqueous-organic, acidic, basic, and enzymatic solutions, were examined for their efficiency in extracting arsenic from finfish, crustaceans, molluscs, and seaweed keeping the chemical forms of the native arsenicals intact. While dilute solutions of nitric acid, hydrochloric acid, and tetramethylammonium hydroxide (TMAH) extract high fractions of arsenic from most of the matrices, the extractants oxidized arsenite (As) to arsenate (As) and converted some arsenosugars and non-polar arsenicals to known and/or unknown forms.

Matrix Extension and Multilaboratory Validation of Arsenic Speciation Method EAM §4.10 to Include Wine.

A multilaboratory validation (MLV) was performed to extend the U.S. Food and Drug Administration's (FDA) analytical method Elemental Analysis Manual (EAM) §4.

Cooking rice in excess water reduces both arsenic and enriched vitamins in the cooked grain.

This paper reports the effects of rinsing rice and cooking it in variable amounts of water on total arsenic, inorganic arsenic, iron, cadmium, manganese, folate, thiamin and niacin in the cooked grain. We prepared multiple rice varietals both rinsed and unrinsed and with varying amounts of cooking water. Rinsing rice before cooking has a minimal effect on the arsenic (As) content of the cooked grain, but washes enriched iron, folate, thiamin and niacin from polished and parboiled rice.

Development of an ion chromatography-inductively coupled plasma-mass spectrometry method to determine inorganic arsenic in liver from chickens treated with roxarsone.

Roxarsone, (4-hydroxy-3-nitrophenyl)arsonic acid, is an arsenic-containing compound that has been approved as a feed additive for poultry and swine since the 1940s; however, little information is available regarding residual arsenic species present in edible tissues. We developed a novel method for the extraction and quantification of arsenic species in chicken liver. A strongly basic solution solubilized the liver, and ultrafiltration removed macromolecules and particulate material.

Quantification of four arsenic species in fruit juices by ion-chromatography-inductively coupled plasma-mass spectrometry.

A method using ion chromatography-inductively coupled plasma-mass spectrometry (IC-ICP-MS) for the quantification of arsenic species in fruit juices has been developed and validated. The method is capable of quantifying four anionic arsenic species - arsenite (As(III)), arsenate (As(V)), dimethylarsinic acid (DMA) and monomethylarsonic acid (MMA) - in the presence of unretained species such as arsenobetaine (AsB). Method validation was based on repeatability, analysis of reference materials, recovery of fortified samples, and determination of detection and quantification limits.

Complementary molecular and elemental detection of speciated thioarsenicals using ESI-MS in combination with a xenon-based collision-cell ICP-MS with application to fortified NIST freeze-dried urine.

The simultaneous detection of arsenic and sulfur in thioarsenicals was achieved using xenon-based collision-cell inductively coupled plasma (ICP) mass spectrometry (MS) in combination with high-performance liquid chromatography. In an attempt to minimize the (16)O(16)O(+) interference at m/z 32, both sample introduction and collision-cell experimental parameters were optimized. Low flow rates (0.

Tissue dosimetry, metabolism and excretion of pentavalent and trivalent dimethylated arsenic in mice after oral administration.

Dimethylarsinic acid (DMA(V)) is a rat bladder carcinogen and the major urinary metabolite of administered inorganic arsenic in most mammals. This study examined the disposition of pentavalent and trivalent dimethylated arsenic in mice after acute oral administration. Adult female mice were administered [(14)C]-DMA(V) (0.

Tissue distribution and urinary excretion of dimethylated arsenic and its metabolites in dimethylarsinic acid- or arsenate-treated rats.

Adult female Fisher 344 rats received drinking water containing 0, 4, 40, 100, or 200 parts per million of dimethylarsinic acid or 100 parts per million of arsenate for 14 days. Urine was collected during the last 24 h of exposure. Tissues were then taken for analysis of dimethylated and trimethylated arsenicals; urines were analyzed for these arsenicals and their thiolated derivatives.

In vitro biotransformation of an arsenosugar by mouse anaerobic cecal microflora and cecal tissue as examined using IC-ICP-MS and LC-ESI-MS/MS.

This investigation examined chemical and microbiological transformations of an arsenosugar by mouse cecum. To mimic the low oxygen environment in the mammalian gastrointestinal tract, reaction mixtures were incubated under anaerobic conditions. An arsenosugar extracted from ribbon kelp, 3-[5'-deoxy-5-(dimethylarsinoyl)-beta-ribofuranosyloxy]-2-hydroxypropanesulfonic acid, As392, was added to reaction mixtures that contained either cecal microflora or cecal tissue homogenate.

Spectroelectrochemical sensing based on attenuated total internal reflectance stripping voltammetry. 2. Determination of mercury and lead.

Detection of lead and mercury by attenuated total internal reflectance spectroscopy coupled to stripping voltammetry is demonstrated. Changes in attenuation of light passing through an indium tin oxide optically transparent electrode (ITO-OTE) accompany the electrodeposition and stripping of lead and mercury on the electrode surface. The change in absorbance during stripping of electrodeposited metal constitutes the analytical response that enables detection over a range of 2.