determining mineral elements in four kinds of grains from beijing market by icp ms simultaneously

ORIGINAL ARTICLEDetermining mineral elements in four kinds of grains from Beijing market by ICP-MS simultaneously a Department of Food Science, Beijing Agricultural College, Beijing 1022

ORIGINAL ARTICLE

Determining mineral elements in four kinds of grains

from Beijing market by ICP-MS simultaneously

a

Department of Food Science, Beijing Agricultural College, Beijing 102206, China

b

College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China

Received 24 August 2010; accepted 17 October 2010

Available online 28 October 2010

KEYWORDS

Grain;

ICP-MS (inductively coupled

plasma mass spectrometry);

Mineral elements;

Minor grains

Abstract Mineral elements are essential components for human health from food, but their con-tents in wheat, millet, corn and soybean have not been compared Concon-tents of mineral elements in wheat, millet, corn and soybean from Beijing market of China were detected by ICP-MS The RSDs (relative standard deviation) range from 0.85% to 3.52% and the detecting limits range from 0.13 to 0.85 lg/L, which showed that this method is accurate and precise to detect mineral elements in grains simultaneously The data showed that (1) ICP-MS is a simple and precise method to deter-mine many deter-mineral elements in grains simultaneously (2) Elements followed by descending order in four grains are usually K > Mg > Ca > Fe > Zn > Mn > Cu > Mo > Li, and grains arranged

in order from high to low levels of mineral elements are usually soybean > millet > wheat corn

So we should take in more minor grains, such as soybean and millet on daily diet

ª 2010 King Saud University Production and hosting by Elsevier B.V All rights reserved.

1 Introduction

Mineral elements are essential for life growth and

develop-ment and they are mostly bound to proteins, forming

metal-loproteins, especially enzymes Usually mineral elements accomplish decisive functions to maintain human health, and their deficiency can lead to undesirable pathological conditions that can be prevented or reversed by adequate supplementation (Cesar, 2005) Most of mineral elements in human body come from daily food, especially grains (Gai

et al., 2004)

Wheat, millet, corn and soybean are four kinds of essential grains in northern China, so determining and com-paring contents of mineral elements in these grains are very meaning for human health ICP-MS (inductively coupled plasma mass spectrometry) is a new method to determine many elements simultaneously and has high accuracy (Rui

et al., 2009a, 2007, 2009b, 2008) So we compared contents

of ten mineral elements in wheat, millet, corn and soybean grains

* Corresponding author Address: Yuanmingyuan Xilu No 2,

Haidian District, Beijing 100193, China Tel.: +86 10 62732574.

E-mail address: ruiyukui@163.com (Y.-K Rui).

1319-6103 ª 2010 King Saud University Production and hosting by

Elsevier B.V All rights reserved.

Peer review under responsibility of King Saud University.

doi: 10.1016/j.jscs.2010.10.014

Production and hosting by Elsevier

Journal of Saudi Chemical Society (2012) 16, 31–33

King Saud University Journal of Saudi Chemical Society

www.ksu.edu.sa

www.sciencedirect.com

2 Materials and methods

2.1 Materials and instruments

Wheat, millet, corn and soybean were brought from

supermar-ket of Beijing The ICP-MS instrument was the PQ Excell

instrument (ELAN DRCII, PE Company, USA)

2.2 Experimental method The samples were prepared by microwave digestion; the micro-wave digestion conditions are shown inTable 1 After cooling the digestion tank, adding volume to 25 mL for detection Detailed methods for these were given byShen et al (2009) and O¨zkan et al (2010) And the operating parameters for ICP-MS are shown inTable 2

3 Results and analysis The relative standard deviations of ten detected elements (Li,

Ca, Mg, Fe, Mn, Cu, Zn, Mo, K and Se) range from 0.85%

to 3.52% and the detecting limits range from 0.13 to 0.85 lg/

L All these data showed that this method can determine these

10 mineral elements simultaneously, and this method is accu-rate and precise (Table 3)

All these four kinds of grains from Beijing market were found with Li, Ca, Mg, Fe, Mn, Cu, Zn, Mo and K, but Se was not found in corn and millet In the four kinds of grains, the list from high to low is K > Mg > Ca > Fe >

Zn > Mn > Cu > Mo > Li, and the list of the four grains

is soybean > millet > wheat corn (Table 4)

4 Conclusions (1) ICP-MS is simple and precise method to determine many mineral elements in grains simultaneously (2) Elements followed by descending order in four grains are usually K > Mg > Ca > Fe > Zn > Mn > Cu >

-Mo > Li, and grains arranged in order from high to low levels of mineral elements are usually soybean > mil-let > wheat corn So we should take in more minor grains, such as soybean and millet on daily diet

Acknowledgements The authors appreciate the financial support of the Programs

of Beijing Emphasis Construction Subjects (No PXM2009_ 014207_078172) We thank Ms Ouyang Li (School of Public Health, Peiking University, China) for detecting

References

Cesar, G.F., 2005 Relevance, essentiality and toxicity of trace elements in human health Mol Aspects Med 26, 235–244 Gai, K., Dong, Y.J., Fu, F., 2004 Brief introduction about the microelement in foodstuff J Longdong Univ (Nat Sci Ed.) 14 (1), 46–48.

O¨zkan, O¨., Safak, U., Nuray, E., 2010 Study on the behavior of the trace metal and macro minerals in Mytilus galloprovincialis as a

Table 1 Microwave digestion temperature control program

Step Maximum power (W) Climb time (min) Pressure (psi) Temperature (C) Hold time (min)

Table 2 Operating parameters for ICP-MS

Method parameters Value

Plasma flow (L/min) 14.0

Nebulizer flow (L/min) 0.98

Auxiliary flow (L/min) 1.20

Sampling depth (mm) 2.0

Replicate read time (s) 10

Instrument stabilization (s) 10

Sample delay uptake (s) 60

Table 3 Relative standard deviations and detecting limits

Elements Detecting limits (lg/L) RSD (%)

Table 4 Contents of 10 mineral elements in four kinds of

grains from Beijing (lg/g)

Mineral elements Corn Soybean Wheat Millet

Li 0.014 0.065 0.020 0.012

Ca 47.69 699.53 200.63 154.20

Mg 313.09 1184.51 321.11 1129.71

Fe 16.99 108.44 19.02 34.13

Mn 1.42 15.11 6.69 11.16

Cu 0.647 6.698 2.896 6.119

Zn 6.11 31.70 8.01 26.89

Mo 0.248 2.403 0.175 0.261

K 1688.87 9611.04 1569.34 2285.54

Se Null 0.352 0.067 Null

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Determining mineral elements in four kinds of grains from Beijing market by ICP-MS simultaneously 33