نوع مقاله : مقاله پژوهشی
نویسندگان
1 گروه علوم ومهندسی خاک، دانشکدگان کشاورزی، دانشگاه تهران، ایران
2 گروه علوم و مهندسی خاک دانشکدگان کشاورزی، دانشگاه تهران، ایران
3 بخش نانوتکنولوژی ' پژوهشگاه بیوتکنولوژی کشاورزی، کرج، ایران
چکیده
کلیدواژه‌ها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Due to the necessity of regular and rapid evaluation of nitrate, the development of methods with the ability to detect this compound accuratly and simple is important. Nowadays, colorimetric methods have received much attention due to their ability to detect simple and visual. In this study, which was carried out in 2022 with cooperation of Tehran university and the Agricultural Biotechnology Research Institute, a colorimetric method based on etching of gold nanorods for qualitative and quantitative detection of nitrate was presented. the measurement of nitrate ions (after reduction of nitrate to nitrite by zinc powder) at room temperature is possible by changing the size of the plasmonic nanoparticles and subsequently generating measurable signals, including spectral and color changes. Under optimal conditions, a good linear relationship between nitrate concentration and colorimetric response in the range of 0.5 to 3.0 mM (R2=0.995) with a detection limit of 173.3 μM was found. Also, considering that vegetables, especially leafy vegetables, have a high potential in nitrate absorption, in this research cress plant was used as an indicator plant to investigate the efficiency of the sensor in determining the nitrate of leafy plants. Recovery values for nutrient solution and cress tissue samples was in the range of 94.4 to 101.9 and 93.4 to 98.5%, respectively, and relative standard deviation (RSD) for all samples was calculated below 2.1%. As a result, the presented method in this study provides the possibility of monitoring the actual level of nitrate in cress plant samples.
کلیدواژه‌ها [English]
Nitrate concentration Measurement in Cress Plant Using a Colorimetric Sensor based on Gold nanoparticles
Extended Abstract
The presence of nitrate in environmental matrices, especially the water-soil-plant system, has raised concerns in the scientific community due to its negative effects on the environment and the health of living organisms. Due to the necessity of regular and rapid evaluation of nitrate, the development of methods with the ability to detect accurate and insitu of this compound is very important. In general, traditional and laboratory methods, despite their high sensitivity, are not very satisfactory due to problems such as time consuming, expensive, inability to measure quickly and the production of chemical waste. Today, colorimetric methods have received much attention due to their ability to detect visually and in situ. Accordingly, in this study, a colorimetric method based on etching of gold nanoparticles with rod shapes for qualitative and quantitative detection of nitrate was presented.
This study was carried out in 2022 at the agricultural biotechnology research institute and the university of tehran, soil science department. Unlike other studies, in this method, instead of temperature, thiourea was used as a sulfur-containing compound to accelerate the etching process of gold nanoparticles. Thiourea accelerates the etching process by forming a complex with gold ions and thus reducing the oxidation potential of Au+ / Au. Therefore, the measurement of nitrite ions at room temperature is possible by changing the size of the plasmon nanoparticles and subsequently generating measurable signals, including spectral and color changes. In addition to nitrite, the developed method is able to determine nitrate indirectly (after reduction of nitrate to nitrite by zinc powder).
Under optimal conditions, a good linear relationship between nitrate concentration and colorimetric response in the range of 0.5 to 3 mM (R2=0.995) with a detection limit of 173.3 μM was found. Also, considering that vegetables, especially leafy vegetables, have a high potential in nitrate absorption, in this research cress plant was used as an indicator plant to investigate the efficiency of the sensor in determining the nitrate of leafy plants. Recovery values for nutrient solution and cress tissue samples were in the range of 94.4 to 101.9 and 93.4 to 98.5%, respectively, and relative standard deviation (RSD) for all samples was calculated below 2.1%. These results show that the proposed measurement system will be able to accurate detection of nitrate content in real samples because a great similarity was observed between the nitrate concentration in the sample (initial concentration + spiked concentration) and the concentration obtained by the sensor.
Evaluation of this sensor using samples of food solution and cress plant shows its ability to measure nitrate concentration with high accuracy and sensitivity in all tested samples. As a result, the method presented in this research makes it possible to measure and monitor the actual level of nitrate in environmental and food samples and can provide valuable data about the amount of these compound in complex matrices.
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