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Rapid Test for Heavy Metal Content in Food

2022-06-26 09:09:39   

Application Overview
    The GB2762-2017 National Standard for Food Safety Limits for Contaminants in Food sets out the limit values for heavy metals such as lead, cadmium, mercury, arsenic, tin, nickel and chromium in different foods. The standard methods for the conventional detection of heavy metals in food are AA, ICP MS, etc. These methods are complex, time-consuming and costly in terms of sample handling and cannot meet the demand for rapid detection of heavy metals in food.

    The PHECDA series of high sensitivity X-ray fluorescence spectrometers use monochromatic focusing excitation technology to significantly reduce the background interference of scattered rays generated by the X-ray tube through the sample and increase the fluorescence intensity of the elements in the sample, reducing the detection limit to 0.05mg/kg for food-based heavy metals, thus meeting the requirements of heavy metal limits in food.

   Fast Fundamental Parametric Method(Fast FP) mathematically models the physics of the various effects of X-ray generation, excitation of sample elemental fluorescence and detector detection, and enables quantitative analysis of sample elements through a large number of calculations and the use of a small number of sample corrections. Fast fundamental parametric method accounts for background differences due to differences in the sample matrix and extends the range of foods detected.

   The combination of a high sensitivity X-ray fluorescence spectrometer and the Fast FP method fills a gap in the current methods for the rapid detection of heavy metals in foodstuffs such as grain, aquatic products, meat and its products, vegetables and fruit, spices, etc., improving the efficiency of detection and safeguarding food safety.

 Food types tested
    Beans and their products, cereals and their products, vegetables and fruits and their products, aquatic products, meat and meat products, spices, nuts, etc.
 Application areas
    Market supervision, customs supervision, public security, food and drug environment and food security, food processing enterprises, food circulation, etc.

Detection limit
        Table of detection limits for food-based heavy metals in PHECDA-PRO

 

Heavy metal elements	Lead	Cadmium	Mercury	Arsenic	Chromium	Nickel	Tin	Thallium
Detection limit①	0.07	0.03	0.1	0.06	0.2	0.1	0.1	0.08

 

Note ①: food matrix, triple standard deviation of seven consecutive analysis results values, elemental analysis time 700 seconds.

Repeatability
        Summary of repeatability for different types of food

Type of food	Number of tests	XRF test value(mg/kg)
		As	Pb	Cd	Cr	Ni	Sn
Soya beans	Fixed value	0.15	0.10	0.12	0.54	3.16	1.15
	Mean(n=7)	0.13	0.10	0.12	0.53	3.23	1.24
	Standard deviation(SD)	0.021	0.023	0.014	0.065	0.064	0.049
	Relative Standard Deviation(RSD)	16%	24%	12%	12%	2%	4%
Pork	Fixed value	0.25	0.30	0.30	1.18	3.22	1.21
	Mean(n=7)	0.30	0.26	0.28	1.31	3.32	1.28
	Standard deviation(SD)	0.039	0.029	0.021	0.076	0.091	0.069
	Relative Standard Deviation(RSD)	13%	11%	8%	6%	3%	5%
Cabbage	Fixed value	0.50	0.40	0.40	2.53	3.46	1.27
	Mean(n=7)	0.56	0.46	0.45	2.44	3.43	1.23
	Standard deviation(SD)	0.026	0.034	0.022	0.083	0.097	0.057
	Relative Standard Deviation(RSD)	5%	7%	5%	3%	3%	5%
Thirteen-spices	Fixed value	1.23	0.49	0.20	2.59	0.08	1.23
	Mean(n=7)	1.23	0.53	0.23	2.47	0.12	1.23
	Standard deviation(SD)	0.033	0.043	0.028	0.089	0.037	0.058
	Relative Standard Deviation(RSD)	3%	8%	12%	4%	30%	5%

 

    Note: The above types of samples are the standard added concentrations of the actual samples.

Accuracy
(1)Accuracy of standard samples
   Different types of food standard samples were used for quantitative analysis, including various types of matrix such as onion, chicken, poplar leaves, scallops and prawns, and the test results are shown in the table below.
     Summary of the accuracy of hazardous elements in various food categories

Sample name	As(mg/kg)			Pb(mg/kg)			Cd(mg/kg)
	Standard values	FP calculated value	Relative error	Standard values	FP calculated value	Relative error	Standard values	FP calculated value	Relative error
GBW10049(Onion)	0.52±0.11	0.50	-3%	1.34±0.16	1.30	-3%	0.19±0.02	0.16	-14%
GBW10018(Chicken)	0.109±0.013	0.14	——	0.11±0.02	0.12	6%	0.005	0.088	——
GBW07604(Poplar Leaf)	0.37±0.09	0.41	13%	1.5±0.3	1.28	-15%	0.32±0.07	0.31	-4%
GBW10024(Scallop)	3.6±0.6	3.5	-4%	0.12	0.18	——	1.06±0.1	1.0	-5%
GBW10022(Garlic Powder)	0.31±0.04	0.30	-5%	0.72±0.09	0.84	17%	0.062	0.08	29%
GBW10050(Prawn)	2.5	2.6	4%	0.20±0.05	0.17	-15%	0.039±0.002	0.05	——
GBW10051(Pig Liver)	1.4±0.3	1.4	3%	0.12±0.03	0.13	9%	1.00±0.07	0.87	-13%
GBW10048(Celery)	0.39±0.08	0.43	10%	2.7±0.7	2.15	-20%	0.092±0.006	0.15	——
GBW10021(Beanstalk)	0.15±0.02	0.22	——	0.66±0.07	0.69	5%	0.02	0.024	24%
GBW(E)100377(Brown Rice)	0.498±0.030	0.58	18%	0.220±0.020	0.16	-26%	0.261±0.020	0.32	24%
GBW(E)100380(Maize)	0.277±0.023	0.337	22%	0.417±0.030	0.39	18%	0.045±0.004	0.09	—
GBW10046(Henan Wheat)	0.025	0.021	-16%	0.067±0.016	0.023	—	0.018±0.002	0.035	—
METAL-DJTZK-014(Brown Rice)	0.616±0.047	0.760	23%	0.340±0.030	0.28	-17%	0.704±0.055	0.79	13%

 

(2) Accuracy of actual samples


Note: The above samples and all test data were completed by the Shanghai Customs Animal, Plant and Food Inspection and Quarantine Centre

Sample handling
(1)Solid samples (grains, pulses, etc.) are tested by crushing and pressing to make pressed samples



(2)Liquid samples (fruit, some vegetables, etc.) are tested by juicing, homogenising and then filling the sample cups


Ancoren provides pre-treatment equipment and standard operating procedures for various food products.

Rapid food heavy metal detection solutions: High sensitivity X-ray fluorescence spectrometer and fast fundamental parameter method

   High sensitivity X-ray fluorescence spectrometer（HS XRF^®）


Monochrome excitation XRF with hyperbolic bent crystal as the core, significantly reducing the scattered ray background, improving the elemental fluorescence signal-to-noise ratio, obtaining food-grade heavy metal detection capability, and reducing the method detection limit to 0.05mg/kg level for lead, cadmium and arsenic in food.

   Advanced Fast Fundamental Parameters Method(Fast FP^®)


The Fast FP method provides automatic baseline deduction and background matching for foods of different matrices, as well as automatic identification and calculation of various interfering spectral lines, and can be used to correct the deviations arising from the calculation by a few standard samples to obtain accurate quantitative values for the elements.


   Highly accurate detection

Obtaining analytical results in agreement with laboratory standard methods, with very low false positive and false negative rates.


   Mobile portability

The PHECDA-PRO weighs 8.7 kg and has excellent portability and is highly adaptable to the environment, operating from -10°C to 40°C.


   Fast detection speed

Fast and simple pre-treatment of food samples, with a detection time of less than 10 minutes to meet the needs of rapid, high-throughput analysis.


References
[1]Liu T, Xing SG, Liu XJ, Wang XJ, Teng F, Liu XD, Xu XL. Rapid determination of arsenic, cadmium and lead elements in food by X-ray fluorescence spectrometry combined with fundamental parameter method[J]. Chinese Journal of Food Hygiene,2021,33(06):790-796.DOI:10.13590/j.cjfh.2021.06.026.
[2] Invention patent A high-sensitivity monochromatic excitation multi-element X-ray fluorescence spectrometer Patent No.: 201510567341.1 Beijing Ancoren Science&Technology Co.,ltd


Original statement:
This article is the original work of ancoren company except for the quotation. If it is forwarded and quoted, the source must be indicated, otherwise it may involve infringement. For more detailed technical information, please consult the staff of Ancoren.

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