Application of Heavy Metal Detection Technology in Rice Quality Testing

Date: 2024-09-27 Click: 2919

Among many crops, rice absorbs more heavy metals. This is mainly because rice requires water nourishment, and under flooded conditions, the activity of heavy metals is very high, which may cause rice to absorb more heavy metals. As a result, problems frequently occur where the heavy metal content in rice exceeds standards. When rice that has absorbed excessive heavy metals is consumed by people, these heavy metals enter the human body, interfering with the normal functioning of organs and even threatening human life. Therefore, relevant departments and personnel need to strengthen the testing of heavy metals in rice. Ensuring that the heavy metal content in rice meets standards will prevent the rice people consume from harming their health.

1. Analysis of the Hazards of Heavy Metals in Rice

Regarding the classification of heavy metals, they mainly refer to metals with a specific gravity above 0.5. Currently, about 45 types of heavy metals have been identified, most of which are transition elements, such as copper, cadmium, and mercury. When the heavy metal content in rice exceeds a certain level, it can pose a certain health risk to humans. Especially lead, cadmium, mercury, chromium, and arsenic, these heavy metals, due to their significant biological toxicity, are referred to as the five poisons. Additionally, heavy metals have certain accumulation and latent characteristics, with a long latency period and strong concealment, making it easy to harm both the environment and human health.

Moreover, if the amount of heavy metals in the food people consume exceeds the standard, it can not only harm the human body but may also lead to a reduction in food production, thereby affecting the economic benefits of growers. Previously, China's Ministry of Land and Resources had released data showing that heavy metal pollution in China leads to a reduction in grain output, approximately 10 million tons per year, and that 12 million tons of food are affected by heavy metal contamination, with these losses totaling up to 20 billion RMB.

From the above data, it can be seen that heavy metals not only harm individuals' interests but also affect the overall national economic benefits. Therefore, heavy metal pollution has attracted attention from all sectors of society in China, and relevant personnel continue to research heavy metal detection technology, hoping to play a certain role in safeguarding the health of the Chinese people and social development.

2. Analysis and Research on Heavy Metal Detection Technology in Rice

At present, since some areas of China exhibit relatively severe heavy metal pollution, the ensuing research on heavy metal detection technology in rice has achieved certain results. This technology can not only quickly detect the heavy metal content in rice but also ensure the safety of Chinese rice.

2.1 Analysis and Detection Methods

(1) Inductively Coupled Plasma Mass Spectrometry (ICP-MS)

Using this detection method, not only can multiple heavy metal elements in rice be detected, but these heavy metal elements can also be analyzed quickly, making it relatively suitable for detecting large batches of rice samples containing multiple elements. For example, when detecting mercury in rice, capillary microextraction coupled with ICP-MS can be used for detection. During the detection process, the detection limit is 3.3 pg/mL, and the effective recovery rate ranges between 89.2% and 101.8%. Although this method provides precise detection, it requires high-end instruments, and the instrument cost is relatively high. In addition, before using this method for detection, the rice samples need pre-treatment, resulting in some elements being undetectable. Therefore, this detection technology is not widely used.

(2) Atomic Absorption Spectroscopy (AAS)

Atomic absorption spectroscopy is currently a commonly used routine method in food testing. When using this technology to detect heavy metals in rice, the first step is to dissolve the matrix modifiers into the rice sample solution to be tested, then stabilize the heavy metal elements in the sample solution, take measures to prevent solution volatilization, and promote the volatility of the matrix in the sample. The main purpose of this process is to prevent the test matrix from being influenced by external factors, thereby avoiding effects on the results.

For instance, when detecting lead in rice, the tester can first add palladium nitrate solution to the standard and sample solutions. During ashing, lead forms a more stable complex with palladium, allowing for higher ashing temperatures without lead loss, thus further removing interfering matrices. Using this method to detect heavy metals in rice not only improves the accuracy of results but also prevents the matrix from affecting the outcomes, making it a widely used analytical detection method today.

3. Conclusion

The presence of heavy metals in rice not only threatens human life safety but also can cause a decline in the overall economy, which has garnered attention from people across various fields in China. Corresponding detection technologies have been developed. Although there are still some issues with these detection technologies, they have achieved significant results, effectively ensuring the safety of rice in China and promoting better development of the country's social and economic sectors.