Rapid Detection of Dimethoate in Soybean Samples by Microfluidic Paper Chips Based on Oil-Soluble CdSe Quantum Dots

Given the imperative of monitoring organophosphorus pesticides (OPs) residues in the ecosystem, here a novel, facile and sensitive fluorescence sensor is presented for the rapid detection of dimethoate. In this work, surface molecularly imprinted polymer (SMIP) and microfluidic technology had been introduced to enhance the selectivity and portability of the described methodology. Oil-soluble CdSe quantum dots (QDs) synthesized in a green way were used as fluorescent material for the selective detection of dimethoate on the basis of static quenching and photoinduced electron transfer mechanism. Among many kinds of paper materials, glass fiber paper was used as the novel substrate of paper chip due to low pristine fluorescence and better performance when combining CdSe QDs. In the process of molecular imprinting, the interaction between several functional monomers and dimethoate molecule was investigated and simulated theoretically by software to improve the selectivity of the sensor. Consequently, the fabricated novel detection platform could effectively respond to dimethoate in 10 min with the concentration range of 0.45–80 μmol/L and detection limit of 0.13 μmol/L. The recovery in the spiked experiment soybean sample was in an acceptable range (97.6–104.1%) and the accuracy was verified by gas chromatography-mass spectrometry, which signified the feasibility and potential in food sampling.

THE PRIMARY STUDY OF SOYBEAN SAMPLE VARIETIES FROM THE COLLECTION OF N.I. VAVILOV RESEARCH INSTITUTE OF PLANT INDUSTRY IN THE CONDITIONS OF THE SOUTHERN FOREST-STEPPE OF THE OMSK REGION

The article presents the results of the primary study of soybean varieties of the world collection of N.I. Vavilov Research Institute of Plant Industry in the conditions of the Omsk region. We identified the samples, which are valuable material for further breeding by several characteristics: the duration of the growth period, productivity.

THE BREEDING EVALUATION OF SOYBEAN GENE POOL FROM THE WORLD COLLECTION OF N.I. VAVILOV ALL-RUSSIAN INSTITUTE OF PLANT GENETIC RESOURCES IN THE CONDITIONS OF THE LOWER VOLGA REGION

The article presents the evaluation results of soybean sample varieties of the world collection of N.I. Vavilov All-Russian Institute of Plant Genetic Resources by economic characters in the conditions of the Lower Volga region. We identified the most early ripening samples by the duration of the growth season and interstage periods. We noted the soybean sample varieties with the highest attachment of the lower bean, the maximum seed weight per plant, thousand-seed weight, and high biochemical seed qualities. We identified the genotypes with an optimal combination of the listed characteristics for further use in various areas of breeding work.

Comparison between devices for homogenization and reduction of soybean grain samples

In the grain market the most diverse equipment is used for homogenization and reduction of the working samples. Thus, this paper aims to analyze the performance of devices used for sample homogenization and reduction for soybean classification. A sample composed of 8% of damaged soybeans with yellow and black coat was previously prepared. Samples were homogenized and reduced in bucket, crate, Boerner, 16:1 multichannel splitter and 4:1 multichannel splitter. The design used was completely randomized with five treatments (homogenizers) and one percentage of damaged grains (8%). Evaluations were subjected to analysis of variance and treatment means were compared to one another by Tukey test (p 0.5) and to the mean of the original sample (8%) by Student s t-test. The devices Boerner, 16:1 multichannel splitter and 4:1 multichannel splitter were similar in the homogenization and reduction of the soybean sample. The crate and bucket showed the worst performance in the grain homogenization because they compromise the result of the product’s qualitative analysis.

A Modified SDS – Based Method Applied for Extraction of High-Quality DNA from Raw Corn and Roasted Soybean

The probability of contamination of non-transgenic varieties with genetically modified (GM) products increase as a result of global expansion of areas sown with transgenic crops. DNA-based methods as accurate, efficient and reliable methods are preferable for detection of GM material in raw or highly processed foods. Isolation of high quality DNA with a suitable and efficient DNA extraction protocol is crucial for getting precise results in DNA amplification. In this study, we performed modifications of previously known Sodium dodecyl sulfate (SDS)-based DNA extraction method regarding the incubation period, DNA pellet washing and addition of organic solvent extraction, to improve DNA quality and to reduce costs. Raw corn kernels and roasted soybean seed were used as samples. DNA was extracted following three protocols, modifications of Edwards protocol. The type of detergent used in raw corn sample did not cause significant effects on extracted DNA yield and purity, while in roasted soybean samples the 2% (w/v) SDS lysis buffer gave the highest DNA yield. The additional incubation step raised the DNA yield from raw corn for 121%, while the purest DNA from soybean sample was obtained using organic solvent extraction. Electrophoretic determination of DNA integrity showed varying degree of DNA smearing from roasted soybean. Contrary, all extraction protocols used on raw corn kernels produced a high molecular weight DNA. Thus, our in-house DNA extraction protocol is as efficient but more cost effective compared to commercial kits and can be used for raw corn, while the protocol for roasted soybean needs further improvement.

Development of simple and sensitive HPLC method for determination of glyphosate residues in soybean

The purpose of this study was to develop a simple and sensitive high performance liquid chromatography (HPLC) method for determination of glyphosate (GP) residues in soybean grains. From soybean matrix, glyphosate was extracted with a mixture of water and methanol (4:1, v/v) from soybean samples followed by protein precipitation with equal volume of methanol. No preconcentration and further clean up of the sample were required. Pre-column derivatization was carried out with excess amount of 9- fluorenylmethyl chloroformate (FMOC-Cl) in the presence of borate buffer. The gradient program developed in this method was successfully applied to a reverse phase HPLC system with a C18 column (ACE 5 μm 4.6 x 250 mm), and eluted with a mobile phase consisting of 50 mM phosphate buffer, pH 2.5, and acetonitrile at the flow rate of 0.8 ml/min and fluorescence detection. Parameters and conditions affecting extraction, derivatization reaction and chromatographic separation were systematically examined. Linearity of the method ranged from 0.005 - 1.0 μg/ml. The correlation coefficient (r2) of calibration curve for glyphosate in soybean sample was found to be 0.99929. The limit of detection (LOD) and limit of quantitation (LOQ) values were determined to be 0.125 mg/kg and 0.25 mg/kg, respectively. Average recovery was 95.2%. Repeatability and intermediate precision calculated on the basis of peak area were excellent and showed relative standard deviation ranged from 0.15 - 1.29% and 1.15 - 3.87%, respectively. The developed method has been successfully applied for determination of glyphosate residues in soybean grains obtained from Thailand and Nepal. Soybean samples (53) from two different lots were analyzed and glyphosate residues ranged from 0.23 mg/kg to 5.06 mg/kg. Almost 50% soybean samples contained nearly consistent residue levels in both lots but in remaining samples there was a significant variation of glyphosate levels between two lots. Relatively higher residues were detected in samples from Thailand (0.27-5.06 mg/kg) compared to Nepal (0.23-0.99 mg/kg). The results suggest that the proposed method can be used to determine glyphosate residues in foods derived from soybean and other crops such as corn, cotton, wheat, etc. where glyphosate is widely applied to these crops.

Standardization parameters for production of tofu using WSD-Y-1 machine

The present work was aimed to standardize different parameters for tofu production using the WSD-Y-1 machine. For this purpose the coagulant variation for production of tofu, shelf life of produced tofu as well as capacity of different parts of the WSD-Y-1 machine was determined. Soybean sample was collected from the Givency Pvt. Ltd., Gazipur. Soymilk was prepared by using the WSD-Y-1 machine. Seven tofu samples were prepared by using different coagulants (CaSO4, MgSO4). TSS variation of the milk was also made. The storage stability of tofu was observed at both room temperature and refrigeration temperature. The yield of tofu varied with coagulants. It was observed that the calcium sulfate gave more yield than magnesium sulfate when the use of both of the coagulants exceeded the single use. Tofu can be kept fresh under water up to one and half of a day and in the refrigerator up to ten days. The operating system of the WSD-Y-1 machine was standardized carefully. There were three operating parts: grinding, heating, and pressing. The grinder was capable to grind about 12-13 kg soybeans at a time. About 45 liter of milk can be heated in the heating system while in the pressing system about 14 liter of milk can be kept for pressing at a time. In this experiment about 1.2 kg of tofu was produced from 1 kg of soybean. On the basis of the work it is recommended that good quality of tofu can be prepared by using the WSD-Y-1 machine which is superior in quality to the hand-made ones. DOI: http://dx.doi.org/10.3329/jbau.v11i2.19930 J. Bangladesh Agril. Univ. 11(2): 307-312, 2013

Development of multielemental imaging on semiconductor Compton telescope

The feasibility of using a Compton camera for multitracer imaging has been demonstrated with the results of two biological sample imaging experiments. The distribution of the multitracer administered to a soybean sample and a tumor-bearing mouse has been visualized for each nuclide simultaneously. 3D images of the multitracer have been obtained even though the samples were measured from a fixed direction.

First Report of Rhizoctonia Foliar Blight of Soybean in South Carolina

Rhizoctonia foliar blight of soybean is found in tropical and subtropical areas worldwide. In the US, it is found mainly in the states of the Gulf Coast region. On 13 September, 2005, the Clemson University Plant Problem Clinic received a soybean sample from Florence County, SC showing severe foliar blight. The cultivars Northrup King 7325 and 76-L9 were affected. Hyphae typical of Rhizoctonia species were observed on the foliar lesions, and the genus was confirmed by microscopic examination. Accepted for publication 7 August 2006. Published 30 October 2006.

Liquid Chromatographic Determination of Flumetsulam in Soybeans

A liquid chromatography (LC) method with UV detection is reported for the determination of the sulfonamide herbicide flumetsulam in soybeans. The ground soybean sample was partitioned between methanol and hexane. The hexane removed the lipids, and the methanol layer containing the analyte was further partitioned between dichloromethane and aqueous phosphate buffer at pH 7.0. The aqueous layer, containing the analyte, was acidified to pH 2.2 and partitioned with fresh dichloromethane. The dichloromethane layer containing the analyte was evaporated, and the residue was dissolved in the LC mobile phase for analysis. A polar embedded C18 column was used with a mobile phase of pH 2.2 aqueous phosphate buffer–acetonitrile (68 + 32), run isocratically with detection at 225 nm. The average recovery was 82% with a relative standard deviation (RSD) of 10%. A coefficient of determination of R2 = 0.9992 was achieved for the analyte calibration curve, from 0.005 to 1 μg/mL. The limit of detection, determined from 3 times the standard deviation of 7 replicate extractions of the lowest fortification level (0.01 μg/g, was 0.005 μg/g with an RSD of 22%. LC/electrospray ionization/mass spectrometry in the positive-ion mode was used for identity confirmation of flumetsulam in the fortified soybean extract. The ions at m/z 326, 348, and 129 were observed.