different levels of arsenic (As), cadmium (Cd) and lead (Pb), followed by drying in a climatic chamber.

Overview

This source page is a mechanical bulk-ingest record for a PDF in the methylmercury infant-formula research pull. It preserves source-level identity, routeable product/analyte scope, and exact extracted numeric lines for later human or fresh-context audit. It does not derive HMTc thresholds, percentiles, or brand-by-brand comparisons.

Key numbers

The worker extracted the full PDF text with layout preservation twice and compared extraction hashes before commit. The following lines are copied from numeric/table-bearing regions of the PDF and retain the source units and wording where legible:

• Chunyapuk Kukusamude 1, *, Supalak Kongsri 1 , Ratchadawan Tamklang 1 and Sutthinun Taebunpakul 2, *
• Technology (Public Organization), 9/9 Moo 7, Saimoon, Ongkharak, Nakhon Nayok 26120, Thailand
• 2 Chemical Metrology and Biometry Department, National Institute of Metrology (Thailand), 3/4-5 Moo 3,
• Technothani, Klong Ha, Klong Luang, Pathum Thani 12120, Thailand
• LA-ICP-MS. Foods 2024, 13, 1604. Keywords: rice; SN-ICP-MS; LA-ICP-MS; matrix-matched material; elemental analysis; calibration;
• Rice is the main staple food especially consumed in most Asian countries (1). Con-
• sion (2). To reduce the risk of consumption, monitoring the levels of contaminants is of
• Licensee MDPI, Basel, Switzerland. requirements (3). For example, atomic absorption spectrophotometry after dry ashing,
• This article is an open access article based on AOAC 999.11, and inductively coupled plasma-mass spectrometry (ICP-MS),
• distributed under the terms and based on AOAC 2015.01, could be used for determining elements in food (4,5). Neverthe-
• 4.0/). employ the external calibration method with calibration standard solutions for elemental
• Foods 2024, 13, 1604. https://doi.org/10.3390/foods13111604 https://www.mdpi.com/journal/foods
• measurement uncertainties (6). The metrological reference values traceable to SI were
• determination (7–9), with access to instruments as a limitation. Therefore, LA-ICP-MS
• digestion process (10). With an acid-free analytical protocol, the technique appears to be
• interest simultaneously (11–16). However, the drawback of LA-ICP-MS analysis is the effect
• entirely representative of the composition of the original sample (17,18). The lack of avail-
• able matrix-matched CRM could hinder the accuracy and precision of this technique (19).
• and carbon as the internal standard (ISTD) for a plant-based and animal-based foods (20).
• Another approach is to use available CRMs: unpolished rice flour CRM and NIES 10a, 10b,
• and 10c to make a pellet (1), with leaf CRMs, NIST1515, NIST1573a, and LGC-7162 (21).
• solutions (22). An alternative approach was performed with the use of matrix-matched
• point calibration (23). Rather than directly pressing the sample into a pellet, investigation
• classify the rice according to its origins and the types of samples (24).
• 2. Materials and Methods
• 2.1. Reagents, Standard Solutions, and Material
• Ultrapure water (resistivity of 18.2 MΩ·cm), used for material cleaning and solution
• MA, USA). Nitric acid, Min. 67% (high purity for trace analysis), purchased from Reagecon
• analysis, NIST standard reference material (SRM) solutions: SRM3103a, SRM3108, and
• SRM3128, traceable to SI units, functioned as calibration standard solutions for determining
• through ICP-MS analysis. Standard solutions NIST SRM 3144 (Rh), NIST SRM 3103a (As),
• SRM 3108 (Cd), and SRM 3128 (Pb) (NIST, Gaithersburge, MD, USA) were used for the
• 2.2. Preparation of Matrix-Matched Material
• Table 1. Preparing composition for matrix-matched material.
• Material Level 1 Material Level 2 Material Level 3 Material Level 4 Material Level 5
• Deionized water 50 mL 50 mL 50 mL 50 mL 50 mL
• Mixture of standard 0 mL equivalent to 1 mL equivalent to 2 mL equivalent to 3 mL equivalent to 5 mL equivalent to
• solutions (6 mg kg−1 0 mg kg−1 for As, Cd 0.2 mg kg−1 for As, 0.4 mg kg−1 for As, 0.6 mg kg−1 for As, 1.0 mg kg−1 for As,
• (12 mg kg−1 of Y equivalent to equivalent to equivalent to equivalent to equivalent to
• as ISTD) 0.4 mg kg−1 Y 0.4 mg kg−1 Y 0.4 mg kg−1 Y 0.4 mg kg−1 Y 0.4 mg kg−1 Y
• colloidal solution, as shown in Table 1. NIST SRM 3167a (Y) was subsequently added to
• For LA-ICP-MS analysis, a sample of 100 mg was pressed into a pellet without any

Methods (brief)

• Elements in Rice Flour by SN-ICP-MS and LA-ICP-MS
• flour matrix is proposed here for the first time as part of a feasibility study using the SN-ICP-MS and
• LA-ICP-MS methods. It was prepared via the spiking process in colloidal solution of rice flour with
• Comparative studies of the results on external calibration and gravimetric standard addition ICP-MS
• the sample matrix. Characterizing the concentration of measurands was then reasonably proposed
• using the gravimetric standard addition ICP-MS. Using powdered rice matrix reference material
• for ICP-MS calibration following acid digestion, the study showed a good agreement of recovery
• studies. A feasibility study of the LA-ICP-MS method as a direct solid analysis performed on the
• An attempt to use of similar matrix in both standard and sample is a critical point to consider to
• Rice Flour by SN-ICP-MS and
• LA-ICP-MS. Foods 2024, 13, 1604. Keywords: rice; SN-ICP-MS; LA-ICP-MS; matrix-matched material; elemental analysis; calibration;
• Licensee MDPI, Basel, Switzerland. requirements (3). For example, atomic absorption spectrophotometry after dry ashing,
• This article is an open access article based on AOAC 999.11, and inductively coupled plasma-mass spectrometry (ICP-MS),
• conditions of the Creative Commons less, based on improving measurement technology, the ICP-MS technique with microwave
• Attribution (CC BY) license (https:// acid digestion has become of increasing interest, as it is capable of both multi-element
• analysis following acid digestion with samples. Since there is a difference between the
• calibration standard and sample nature, the matrix effect can be an issue that may influence
• Due to the fact that there is a difference arising from the nature of the sample matrix

Implications

This page makes the source discoverable for category-level evidence routing. Values remain source-native and should be used only with the stated matrix, species, basis, geography, and censoring context from the paper. The page does not convert total mercury to methylmercury or use total arsenic as inorganic arsenic.

Wiki pages this source may touch

• Fish — marine, non-predatory (sardines, anchovies, salmon, cod)
• Cadmium
• Lead
• Arsenic
• Nickel
• Tin

Verification notes

• Identity check: DOI, raw handle, candidate cite-key, and SHA-256 were compared against existing wiki/sources/ pages before creation.
• Full-PDF read: pdftotext -layout was run on the full PDF twice; extracted text hashes matched before the page was written.
• Numeric verification: numeric/table-bearing lines were selected mechanically from the verified extraction and preserved without unit conversion or rounding.
• Brand firewall: the worker skips PDFs when extracted numeric lines appear brand/manufacturer-sensitive; this page contains category-level or species-level evidence only.
• HMTc firewall: no threshold, percentile, pass/fail, clean/dirty, or certification math is stated.

Update history

The five most recent substantive edits to this page, classified major (evidence or structure moved), correction (a published value or statement was wrong and has been fixed), or minor (narrative rewritten without changing the underlying evidence). Each description is derived from what the edit did to this page; the linked commit is the authoritative record, routine regeneration passes are excluded, and the full version history lives in git. When DOI minting comes online (see schema docs), each entry below will also link to a version-pinned DataCite DOI.