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Measured intensity ratio
Measured intensity ratio
Measured intensity ratio
Standard value (μg/g) Standard value (μg/g) Standard value (μg/g)
Fig. 1 ALTRACE
Calibration curves were prepared for cadmium (Cd), arsenic (As),
and lead (Pb) using standard solutions for atomic absorption
spectrophotometry adjusted to the four concentration levels
shown below. Fig. 2 shows the calibration curves.
Here, correction of the sample shape and matrix was done with
scattered X-ray. In addition, correction for overlap of As by Pb
was also carried out (coexisting element correction, dj method).
Concentrations of calibration curve standard solutions:
0 (blank), 0.5, 1, 5 μg/g
Calibration Curves
Table 1 Lower Limits of Detection
Control of hazardous heavy metals contained in foods and food
additives is required in order to protect human health and safety.
Therefore, various domestic laws and regulations
(1)-(4)
have been
established in Japan, including “Standards and criteria for food
and food additives, etc.” and “Japan’s Specifications and
Standards for Food Additives”.
From the viewpoint of sensitivity, the main technique used in
analyses of toxic heavy metals is atomic absorption
spectrophotometry. However, as disadvantages of this method,
powder and solid samples must be dissolved in an acid such as
nitric acid or hydrochloric acid, and advanced technology and
know-how are required in the actual analysis. In contrast,
fluorescent X-ray spectroscopy offers excellent convenience
because analysis is possible as-is, without dissolving the
specimens.
Shimadzu’s new product, the ALTRACE, energy dispersive X-ray
fluorescence spectrometer (Fig. 1), makes it possible to analyze
toxic heavy metals with high sensitivity thanks to the increased
output of the X-ray tube and optimization of the optical design.
As an additional advantage, continuous analysis of a maximum of
48 samples is possible, contributing to improved analysis
throughput.
This Application News article introduces the following:
1. Analysis of cadmium (Cd) in rice
2. Analysis of arsenic (As) and lead (Pb) in food additives
Introduction
In comparison with the conventional technology, sensitivity was improved by high voltage X-ray tube and optimization of the
optical design.
Analysis throughput is improved because continuous analysis of a maximum of 48 samples is possible.
Screening for hazardous elements in foods and food additives is possible with only simple sample preparation, such as loading
the samples into the sample container.
Screening Analysis for Hazardous Heavy Metals
in Foods and Food Additives
Kotomi Kuroda, Hirokazu Moriya
Energy Dispersive X-ray Fluorescence Spectrometer ALTRACE
Table 1 shows the lower limits of detection of each element
calculated from the theoretical statistical variation of the
calibration curves.
Lower Limit of Detection
Element Cd As Pb
Analytical line CdKα AsKα PbLβ1
Lower limit of detection 0.08 0.08 0.10
Pb Cd As
Degree of accuracy (σ) = 0.037 µg/g Degree of accuracy (σ) = 0.030 µg/g Degree of accuracy (σ) = 0.066 µg/g
Fig. 2 Calibration Curves
[μg/g]
