Objective: The aim of this research was to determine arsenic concentration in infant rice cereals and to find out whether arsenic levels from infant rice cereals still meet the standards set by the National Agency of Drug and Food Control of Republic of Indonesia (NADFC). Method: The arsenic concentration was determined with an ICP-MS method and the analytical method was validated by measuring accuracy, precision, detection limits and quantitation limits. Result: The results of the validation method were obtained recoveries of spiked sample 96.06%, RSD 2.33%, limit detection and limit quantification 0.24 µg kg-1 and 0.78 µg kg1. The arsenic levels in infant rice cereals were in the range 12.30 – 106.15 µg kg-1 (n=12), on average they were 35.57 µg kg-1. Conclusion: Arsenic concentration in infant rice cereals maximum 20 µg/kg, there are nine samples whose arsenic levels exceed the requirements
Keywords: Arsenic; Infant rice cereals; Baby Rice; Inductively Coupled Plasma-Mass Spectrometry
Arsenic is an element in the earth's crust and is very small in water, soil and air from volcanic eruptions and industrial activities such as mining, smelting and burning coal. Arsenic is also used as wood preservatives, pesticides, fertilizers, additives for animal feed and as medicinal ingredients [1].
Arsenic is a metal that belongs to a group of human carcinogens that cause cancer of the skin, kidneys, bladder and lungs [2]. Chronic effects of arsenic exposure cause skin lesions, neurotoxicity, cardiovascular disease, diabetes and cancer [3].
Babies are a population group that is most vulnerable to the toxic effects of arsenic due to higher absorption of arsenic in the digestive tract, faster metabolic processes, detoxification systems that are not fully developed and more food consumption when compared to body weight. [4].
Rice is a staple food that is widely consumed by people in the world and it is also a food source that is often exposed to arsenic. Rice exposed to arsenic comes from the use of pesticides, fertilizers and soil and irrigation water contaminated by arsenic [5].
Generally, mothers introduced rice cereal as the first solid food for infants aged 4-6 months [6]. Arsenic exposure to food is estimated to be about three times higher in infants than in adults, because intake per weight is higher in infants, in addition to less infant food diversity than adults [7].
Samples of infant rice cereals (n=12) obtained from baby shop or supermarket in Indonesia. The sampling method was carried out purposively on the consideration that the most material composition in the sample was made from rice and each brand was represented by one sample.
-1 Ultrapure water (resistivity 18 MΩ cm ) from a Milipore water purification system was used throughout this study. Suprapur grade HNO (65%) and H O (30%) were 3 2 2 purchased from Merck. Arsenic standard solutions grade -1 ICP-MS (1000 μg mL ) was obtained from Merck (Germany).
All of the measurements were conducted using an ICP- MS (Agilent 7800) instrument with PeriPump sample introduction, MicroMist nebulizer, x-lens ion lens, Scotttype double-pass spray chamber and helium collision mode. Standard, blank and sample solutions were delivered using autosampler. Instrument performance was -1 checked using tuning solution containing with 1 μg L Ce, Co, Li, Mg, Tl, Y (Agilent). Based on the instrument manufacturer, the following parameters were checked during the daily performance analysis: sensitivity (Li, Y and Tl), doubly charges (Co) and oxides (Ce) ratio. ICP- MS Operating conditions are shown in Table 1.
The solid samples were homogenized by blender to become a fine powder. The powdered samples were weighed accurately to a weight of 0.5 g into a microwave vessel, added with 5 mL of 65% HNO3 and 1 mL of 30% H2O2. Then let stand for 10 minutes so the sample dissolves. The vessel is put into the microwave (CEM o o MARS 6) at 200 C using 4 stage program: to 100 C in 5 o o minutes, to 130 C in 5 minutes, to 160 C in 5 minutes, to o 200 C in 7 minutes and held for 10 minutes and cooling o down to 80 C. Samples were cooled to room temperature and transferred into a volumetric flask 25 mL and the vessel is rinsed with ultrapure water up to 25 mL. The sample solution was analyzed for arsenic concentration
using Inductively Coupled Plasma-Mass Spectrometer at m/z 75.
Method validation was performed with parameters of linearity, accuracy, precision, detection limit and quantitation limit. Linearity was obtained by preparing a calibration curve from several concentrations of the standard solution and the calculation of the correlation coefficient (r). Accuracy was established by adding standard solution method, and then proceeds with sample analysis procedure as previously done using Inductively Coupled Plasma-Mass Spectrometer at m/z 75, while precision was measured as relative standard deviation. Determination of detection limits and quantitation limits based on the calculation of the calibration curve obtained.
From the validation study, it can be showed that excellent trueness (% recovery) and good precision were obtained. The detection limit and quantification limit achieved were low enough and suitable for determining arsenic in infant rice cereal at the low levels found in the samples. Method validation performed are shown in table 2.
D Rice cereal Indonesia 1974.6711 E Rice single grain USA 11319.5778 cereal 11029.2611 F Rice cereal England 5649.1344 G Mixed grain cereal England 4518.7144 H Baby rice Indonesia 2248.0578 I Organic baby rice Indonesia 3538.3744 J Organic baby rice Indonesia 1637.9544 K Organic baby rice Indonesia 7339.9644 L Organic baby rice Indonesia 2838.2044 48.5519 17.1412 17.2678 0.3060 17.2018 17.4692 17.7336 16.8333 17.2275 106.8816 106.1521 0.7227 106.4624 106.3808 105.2012 105.2948 106.6917 52.9678 53.3029 0.4705 53.4488 52.5879 53.2587 53.8495 53.7047 41.7068 42.2856 0.5729 42.8584 42.5061 42.7157 42.4812 41.4453 18.5381 18.6974 0.1584 18.8767 18.7090 18.8986 18.5909 18.5711 31.0783 32.1317 0.6746 32.6541 31.6065 32.7122 32.6582 32.0809 12.2366 12.3011 0.3347 12.0338 12.8244 12.0361 12.0755 12.6001 68.6526 67.9254 0.7434 68.9687 67.4085 67.6519 67.8374 67.0331 21.9303 21.6829 0.2040 21.6102 21.3790 21.8308 21.5570 21.7898
Table 3 shows that infant rice cereal contains different concentration of arsenic for each sample. The safety of infant rice cereal in this study refers to the arsenic safe limit stipulated by the regulation of the NADFC in 2017 about the maximum limit of heavy metal contamination -1 in processed foods which is not more than 20 μg kg [8].
Based on Figure 1, a total of 12 infant rice cereal samples were tested, there was only three sample whose arsenic concentration met the NADFC requirements, it was D, H and J with arsenic levels of 17.2678; 18.6974; 12.3011 μg -1 kg and there were nine samples whose arsenic levels exceeded the NADFC requirements, that is between -1 -1 21.6829 μg kg to 106.1521 μg kg . Sample E with the highest arsenic concentration which reached five times the required by the NADFC.
Based on Table 3, arsenic concentration produced in USA are higher than those produced in Indonesia. Arsenic levels in rice and rice-based products vary due to species and genetic differences from rice, arsenic concentrations in soil and irrigation water, rice planting methods and history of the use of pesticides and chemical fertilizers on agricultural land [9, 10]. Geographical factors of soil can also cause arsenic levels in baby food products derived from rice to vary [11]. The results of research by Williams, et al., (2005) reported that arsenic levels in rice originating from India were lower than rice originating from Bangladesh, Europe, America. Average arsenic levels in rice from India was 0.05 μg/g; rice from Bangladesh was 0.13 μg/g; rice from Europe was 0.18 μg/g; rice from America was 0.26 μg/g [12].
Rice-based baby foods are likely to contain arsenic derived from the composition of ingredients or because of contamination during food processing [2]. When it is stated that rice flour is the most important and dominant composition in baby food, arsenic levels in the sample are higher than baby food mixed with other food ingredients [13].
In general, infant rice cereals are widely used during weaning young children because it is easy to get, the price is cheap, bland taste, nutritional value and low allergic potential. Different trademarks affect arsenic levels in baby rice cereals because it is related to the amount of rice in the product, rice origin and manufacturing process. The results of this study showed that 9 of the 12 infant rice cereal samples tested were higher than the NADFC maximum level. Our study suggests that cereal makers need to take immediate steps to reduce arsenic in their infant rice cereal. This action is especially needed to protect infants who rely on rice-based cereal as a staple food.
The author would like to thank NADFC of Republic of Indonesia for financial support and opportunity to study in Universitas Sumatera Utara and NADFC of Pekanbaru for research in the laboratory.