Determination of Inorganic Arsenic in Fish Oil and Fish Oil Capsules by LC-ICP-MS.

BACKGROUND: As inorganic arsenic is a highly toxic compound, its concentration in foods should be determined. OBJECTIVE: Develop an analytical method for determining inorganic arsenic in fish oil and fish oil capsules. METHOD: Inorganic arsenic was extracted from fish oil by heating at 80°C in 1.6% tetramethylammonium hydroxide-ethanol. The concentration of inorganic arsenic in fish oil was determined by liquid chromatography (LC) inductively coupled plasma (ICP) MS using an octadecylsilane (ODS) column with a mobile phase containing an ion-pair reagent. RESULTS: The LOD (0.005, 0.004 mg/kg), LOQ (0.016, 0.011 mg/kg), repeatability (4.2, 3.5%), intermediate precision (5.4, 3.5%), and trueness (recoveries 94-109% based on spiked samples) of the proposed method were satisfactory for inorganic arsenic in fish oil and fish oil capsules. A low level of inorganic arsenic was detected only in anchovy oil among all fish oil samples that were used in this study. Inorganic arsenic levels were below the quantitation limit in all fish oil capsules. CONCLUSIONS: Inorganic arsenic was determined after extraction from fish oil by heating at 80°C in 1.6% tetramethylammonium hydroxide-ethanol. The level of inorganic arsenic in all fish oil samples examined in this study was lower than 0.1 mg/kg of the maximum level defined in the Codex. HIGHLIGHTS: Arsenic speciation in fish oil and fish oil capsules was analyzed by LC-ICP-MS using an ODS column with a mobile phase containing an ion-pair reagent. A low level of inorganic arsenic was detected only in anchovy oil. No inorganic arsenic was detected in fish oil capsules.

Determination of Inorganic Arsenic in Seaweed and Seafood by LC-ICP-MS: Method Validation.

Background: Seaweed and seafood often contain both inorganic and organic arsenic compounds showing distinct toxicities. Speciation must be taken into account when determining the concentrations of arsenic compounds and how they relate to overall toxicity. Objective: An analytical method for the quantitation of inorganic arsenic was validated in seaweed and seafood. Methods: Food samples were heated at 100°C in 0.3 mol/L nitric acid. Arsenic speciation was quantitatively determined by LC-inductively coupled plasma-MS (LC-ICP-MS) using an octadecilsilane (ODS) column with a mobile phase containing an ion-pair reagent. Results: Limits of detection (0.0023-0.012 mg/kg), LOQ (0.0077-0.042 mg/kg), repeatability (3.0-7.4%), intermediate precision (4.4-7.4%), and trueness (recoveries 94-107%) of the proposed method were satisfactory for inorganic arsenic in seaweed and seafood. Inorganic arsenic was detected in almost all the evaluated dried seaweed products, the Japanese oyster, nam pla, oyster sauce, and the intestinal organs of seafood. Conclusions: Among the dried seaweed products, significant inorganic arsenic was detected in the brown algae akamoku, hijiki, and mozuku. The small amounts of inorganic arsenic detected in nam pla and oyster sauce likely derive from the internal organs of the raw seafood used in their preparation. Highlights: Arsenic speciation in seaweed and seafood was measured by LC-ICP-MS using an ODS column with a mobile phase containing an ion-pair reagent. Among the dried seaweed products, brown algae akamoku, hijiki, and mozuku contained significantly high levels of inorganic arsenic. The intestinal organs of oyster, sardine, and scallop contained higher arsenic levels than the muscles.

[Establishment of Test Methods for Overall Migration Test into Vegetable Oil Applied to Food Contact Materials Intended for Contact with Oils and Fatty Foods].

The evaporation residue test designated in the Japanese Food Sanitation Act is used to determine the total migration amount of substances that food contact materials release into foods. Vegetable oil would be the most suitable food simulant for oils and fatty foods, but it is difficult to remove by heating due to its high boiling point, so heptane and 20％ ethanol are used as substitute food simulants in the test for plastics and rubbers. The EU has introduced an overall migration test into olive oil for plastics intended to come into contact with oils and fatty foods. This test method is described in European Standard EN1186-2. However, this method has several problems. Therefore, we improved the procedures for weighing samples in a desiccator containing 43％ sulfuric acid, extraction of the absorbed vegetable oil using the soaking method with an internal standard, methyl esterification of vegetable oil using sodium methoxide, and the GC conditions for the determination of vegetable oil. The improved method is simpler and much quicker than the original method, and the harmfulness of the reagents is reduced. It can be applied to both plastics and rubbers. Comparative trials showed that the results obtained with this method and EN1186-2 method are equivalent.

[Trace Analysis of Lead in Copper Gluconate by Atomic Absorption Spectrometry after Separation by Co-Precipitation with Bismuth].

In order to determine trace amounts of lead in copper gluconate by atomic absorption spectrometry (AAS), the authors investigated a separation and pre-concentration procedure using a co-precipitation technique with bismuth. After ashing 2.0 g of the sample by means of a dry process, the ash was dissolved in (1→100) nitric acid and 75 µg of bismuth was added. Lead was co-precipitated by using an ammonium solution controlled to pH 9.5-10.5. The precipitate was left at room temperature for over 15 minutes to age, and then washed with a (3→100) ammonium solution three times. The precipitate was dissolved in (1→100) nitric acid and then analyzed by AAS. The quantification limit of this method was 0.5 mg/kg, and the trueness, repeatability and intermediate precision were 99.6%, 4.2% and 4.2% at the spiked concentration of 0.5 mg/kg, and 94.4%, 2.8% and 4.0% at the spiked concentration of 5.0 mg/kg, respectively. Thus, the present method for trace analysis of lead in copper gluconate was validated.

Three-Dimensional Visualization of Developing Neurovascular Architecture in the Craniofacial Region of Embryonic Mice.

Recent studies have highlighted the mechanism of vascular and axonal guidance to ensure proper morphogenesis and organogenesis. We aimed to perform global mapping of developing neurovascular networks during craniofacial development of embryonic mice. To this end, we developed histology-based three-dimensional (3D) reconstructions using paraffin-embedded serial sections obtained from mouse embryos. All serial sections were dual-immunolabeled with Pecam1 and Pgp9.5/Gap43 cocktail antibodies. All immunolabeled serial sections were digitized with virtual microscopy to acquire high spatial resolution images. The 3D reconstructs warranted superior positional accuracy to trace the long-range connectivity of blood vessels and individual cranial nerve axons. It was feasible to depict simultaneously the details of angiogenic sprouting and axon terminal arborization and to assess quantitatively the locoregional proximity between blood vessels and cranial nerve axons. Notably, 3D views of the craniofacial region revealed the following: Branchial arch arteries and blood capillary plexi were formed without accompanying nerves at embryonic day (E) 9.5. Cranial nerve axons began to grow into the branchial arches, developing a labyrinth of small blood vessels at E10.5. Vascular remodeling occurred, and axon terminals of the maxillary, mandibular, chorda tympani, and hypoglossal nerve axons had arborized around the lateral lingual swellings at E11.5. The diverged patterning of trigeminal nerves and the arterial branches from the carotid artery became congruent at E11.5. The overall results support the advantage of dual-immunolabeling and 3D reconstruction technology to document the architecture and wiring of the developing neurovascular networks in mouse embryos.