Determination of Pb (Lead), Cd (Cadmium), Cr

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:

• Article history: The contents of lead, cadmium, chromium, copper, and nickel were determined in 25 tea
• Received 8 November 2014 samples from China, including green, yellow, white, oolong, black, Pu’er, and jasmine tea
• 16 March 2015 trometry. The methods used for sample preparation, digestion, and quantificational analysis
• Accepted 5 May 2015 were established, generating satisfactory analytical precisions (represented by relative standard
• Available online 18 July 2015 deviations ranging from 0.6% to 2.5%) and recoveries (98.91e101.32%). The lead contents in tea
• leaves were 0.48e10.57 mg/kg, and 80% of these values were below the maximum values stated
• Keywords: by the guidelines in China. The contents of cadmium and chromium ranged from 0.01 mg/kg to
• Chinese tea 0.39 mg/kg and from 0.27 mg/kg to 2.45 mg/kg, respectively, remaining in compliance with the
• continuum source graphite furnace limits stipulated by China’s Ministry of Agriculture. The copper contents were 7.73e63.71 mg/kg;
• atomic absorption spectrometry only 64% of these values complied with the standards stipulated by the Ministry of Agriculture.
• heavy metals The nickel contents ranged from 2.70 mg/kg to 13.41 mg/kg. Consequently, more attention must
• Copyright © 2015, Food and Drug Administration, Taiwan. Published by Elsevier Taiwan
• creativecommons.org/licenses/by-nc-nd/4.0/).
• 1. Introduction provide antiaging activities, and decrease the risks of both
• cardiovascular disease and cancer (1). However, heavy metal
• University of Technology, Pingleyuan No. 100, Chaoyang District, Beijing 100124, China.
• 1021-9498/Copyright © 2015, Food and Drug Administration, Taiwan. Published by Elsevier Taiwan LLC. This is an open access article under the CC
• BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
• telligence and nervous systems (2e5). Cadmium (Cd) accu- 2. Materials and methods
• the renal cortex), lung, and heart, and is toxic to bones and 2.1. Instruments and reagents
• Agency for Research on Cancer and the National Toxicology A ContrAA 700 (Analytik Jena AG, Jena, Germany) high-
• Program, and Cd has been classified as a Group 1 carcinogen resolution continuum source atomic absorption spectrom-
• (5e12). Chromium (Cr) can exist in several oxidation states. eter equipped with a short-arc xenon lamp, a high-resolution
• harmful to the skin, liver, kidney, and respiratory organs (13), device array detector was used. An MPE-60 autosampler for
• necrosis, perforation of the nasal septum, and lung cancer (99.999%) was supplied as the protective and purge gas. The
• (14). Cr is also a Category 1 carcinogen according to the In- method was optimized based on the proper atomic lines for Pb
• ternational Agency for Research on Cancer and the National (283.306 nm), Cd (228.802 nm), Cr (357.869 nm), Cu
• Toxicology Program (11,12). Excessive copper (Cu) intake can (324.754 nm), and Ni (232.003 nm). A BT-214D electronic bal-
• and central nervous system inhibition (15). Nickel (Ni) is pri- samples. An ETHOS A Microwave Digestion System (Mile-
• to its mutability and carcinogenicity (16). Ni is also a Category The certified reference material for Green Tea (GBW 10052)
• 1 carcinogen (11,12). and the standard solutions (100 mg/L Pb, 1000 mg/L Cd,
• Numerous techniques have been employed to analyze the 1000 mg/L Cr, 1000 mg/L Cu, and 1000 mg/L Ni) were purchased
• tion spectrometry (FAAS) (17,18), graphite furnace atomic ab- Materials of China (Beijing, China). The working standard so-
• sorption spectrometry (GFAAS) (19,20), inductively coupled lutions were prepared daily through a stepwise dilution of the
• plasma atomic emission spectroscopy (ICP-AES) (21), and standard stock solutions using 0.5% (v/v) nitric acid (HNO3),
• inductively coupled plasma mass spectrometry (ICP-MS) (22). ammonium phosphate monobasic (NH4H2PO4), and magne-
• GFAAS is a useful tool for studying trace metals because it is sium nitrate (Mg(NO3)2) (Sigma-Aldrich, St. Louis, MO, USA)
• highly accurate, sensitive, and selective. Ning et al (20) were used as chemical modifiers for the determination of the
• investigated the Pb, Cd, and Cu contents in 30 brands of Chi- Pb, Cd, Cr, Cu, and Ni levels. The reagents were of analytical
• (12.22e22.22 mg/kg) was the highest. Khakhathi et al (23) (18.2 MU/cm) produced using a PureLab Prime system (PALL,
• and infusions of black, green, and herbal teas using GFAAS, cleaned by soaking in the 5 mol/L HNO3 for at least 24 hours and
• High-resolution continuum source atomic absorption 2.2. Sample preparation

Methods (brief)

• graphite furnace atomic absorption spectrometry
• Received 8 November 2014 samples from China, including green, yellow, white, oolong, black, Pu’er, and jasmine tea
• Received in revised form products, using high-resolution continuum source graphite furnace atomic absorption spec-
• 16 March 2015 trometry. The methods used for sample preparation, digestion, and quantificational analysis
• atomic absorption spectrometry only 64% of these values complied with the standards stipulated by the Ministry of Agriculture.
• nogenic properties, and it impairs both the respiratory and Pu’er, and jasmine tea were determined using HRCS-AAS.
• Program, and Cd has been classified as a Group 1 carcinogen resolution continuum source atomic absorption spectrom-
• harmful to the skin, liver, kidney, and respiratory organs (13), device array detector was used. An MPE-60 autosampler for
• causing various diseases, such as dermatitis, renal tubular liquid samples was installed on the GFAAS. High purity argon
• and central nervous system inhibition (15). Nickel (Ni) is pri- samples. An ETHOS A Microwave Digestion System (Mile-
• marily accumulated in the spinal cord, brain, and organs due stone, Milano, Italy) was used for the samples digestion.
• tion spectrometry (FAAS) (17,18), graphite furnace atomic ab- Materials of China (Beijing, China). The working standard so-
• sorption spectrometry (GFAAS) (19,20), inductively coupled lutions were prepared daily through a stepwise dilution of the
• plasma atomic emission spectroscopy (ICP-AES) (21), and standard stock solutions using 0.5% (v/v) nitric acid (HNO3),
• inductively coupled plasma mass spectrometry (ICP-MS) (22). ammonium phosphate monobasic (NH4H2PO4), and magne-
• GFAAS is a useful tool for studying trace metals because it is sium nitrate (Mg(NO3)2) (Sigma-Aldrich, St. Louis, MO, USA)
• nese Pu’er tea using GFAAS and observed that the Cu content grade, and all solutions were prepared using deionized water
• and infusions of black, green, and herbal teas using GFAAS, cleaned by soaking in the 5 mol/L HNO3 for at least 24 hours and

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

• Seaweed/kelp foods (nori, wakame, kombu, dulse — as food products)
• Mercury
• Cadmium
• Lead
• Arsenic
• Nickel
• Aluminum
• Chromium

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.