A  Spectrophotometric Determination of Myclobutanil and it’s Applications

Ajay kumar Sahu^a, Shraddha Ganesh Pandey^a, Vindhya Patel^a, Raisa Khatoon^a, Mamta Nirmal^a, Kalpana Wani^a, Deepak Kumar Sahu^a,b, Jyoti Goswami^a , Chhaya Bhatt^a, Geetanjali Deshlahare^a_, Harshita Sharma^a, Manish Kumar Rai^a* and Joyce Rai^b

^aSchool of Studies in chemistry Pt. Ravishankar Shukla University Raipur(Chhattisgarh), 492010, India

^bChhattisgarh Council of Science and Technology, Vigyan Bhawan Vidhan Sabha Road Daldal Seoni, Raipur (Chhattisgarh) 492014, India

*Corresponding Author:  mkjkchem@gmail.com

[Received: 20 February 2018; Revised version: 10 April 2018; Accepted: 18 April 2018]

Abstract: A new spectrophotometric method has been developed for determination of fungicide myclobutanil is based on the bromination of myclobutanil to form dibromo myclobutanil which react with Potassium iodide-Potassium iodate mixture in the presence of leucocrystal voilet (LCV) to form a violet colored complex. The complex shows maximum absorbance at 590 nm. Beer’s law obeyed over the concentration range of 0.5-4.0 µg in final solution volume of 10 mL. The reproducibility assessed by carrying out seven days replicate analysis of a solution containing 10 µg of myclobutanil in a final solution of 10 mL. The molar absorptivity of the coloured system is 1.29×10⁵ L mol^-1cm^-1 and Sandell’s sensitivity is 1.03×10^-3 µg cm^-2. The standard deviation and relative standard deviation for the absorbance value were found to be ±0.00652 and 1.14% respectively. The proposed method is free from the interference of other toxicants. The analytical parameters were optimized and the method was applied to the determination of myclobutanil in water, soil and food samples.

Keywords: Mycobutanil, Leucocrystal violet, Bromination, Spectrophotometric method.

Introduction

Myclobutanil (C₁₅H₁₇N₄Cl, chemically named a-butyl-a-(4-chlorophenyl)-1H-1,2,4-triazole-1-propane nitrile) (Figure 1.), is a high-efficiency, low toxicity and wide spectrum triazole fungicides. It is used in control of Ascomycetes, Fungi Imperfecti and Basidiomycetes on a wide variety of crops (Yan, et al., 2016).  Myclobutanil is an important systemic trizaole fungicides, it was developed by Dow Agro-Sciences and first marketed in 1989. Currently, myclobutanil is widely used to control various fungal diseases in fruits, cereals, vegetable crops, and also in lawn care and wood preservations. It is formulated as a wettable powder, emulsifiable concentrate, granular, dust, and dry flowable and ready to use forms. It is also known to be stable to both hydrolysis and photolysis. As a treatment to crops, this compound is applied at multiple plant growth stages (e.g. seed, pre-bloom, bloom, foliar, post-bloom etc.). The adverse effects of myclobutanil on non-target species cannot be ignored. Myclobutanil demonstrates moderate acute toxic (Han et al., 2017).

Due to extensive use and toxicity various methods have been suggested for the deduction of mycobutanil such as High-Performance Liquid Chromatography/Tandem Mass Spectrometry. Yeast-Based Bioassays, Gas Chromatography – Electron Capture Detector, Liquid Chromatography–Mass Spectrometry/Mass Spectrometry (Lin et al., 2018; Westlund et al., 2017; Suyal et al., 2016; Chen et al., 2014).

                            Figure 1. Structure of Myclobutanil

Materials and Method

Apparatus

All spectral measurements have been made by a systronics UV-VIS spectrophotometer model-167 with 1 cm matched quartz cell. A systronics digital pH meter model 335 has been used for pH measurements. A remi C-854/4 clinical centrifuge force of 1850 rpm with fixed swing out rotors was used for centrifugation. Calibrated glassware have been used after getting cleaned by soaking in acidified solution of potassium dichromate followed by washing soap water and rinsing two times with distilled water.

Reagents and Materials

All reagents used have Anala. R. Grade and double distilled water have been used throughout the experiment. A standard stock solution of 1mg/mL solution of mycobutanil (Makhteshim-Agan India Pvt. Ltd) is prepared in double distilled water. Working standard have been prepared by proper dilution of stock solution. 5M sodium hydroxide solution have prepared with distilled water. A saturated solution of bromine in water have prepared. The 90% solution of formic acid have prepared in distilled water. 0.1mol L^-1aqueous solution of potassium iodide (BDH) and 0.2 mol L^-1 aqueous solution of potassium iodate (MERCK) are also prepared in distilled water. The potassium iodide-potassium iodate mixture have prepared by mixing 0.1mol L^-1 potassium iodide and 0.2 mol L^-1 potassium iodate in 5:1 ratio.

Procedure

An aliquot of the sample containing 0.5-5.0 µg of mycobutanil were transferred into 25 mL volumetric flask, 0.5 mL of bromine water were added and the mixture shaken gently for 2 minutes. The excess of bromine was removed by addition of 2-3 drops of Formic acid after which 1mL of mixture of potassium iodide-potassium iodate (5:1) along with 0.5 mL of sodium acetate buffer and 1mL of leucocrystal violet have been added and solution left for 10 minutes undisturbed as violet colour dye appears. Makeup the volume up to the mark with water and analyse the absorbance at 590 nm taking blank solution as reference.

Results and discussion

Spectrul characteristics

The violet colour dye formed in the present method shows maximum absorbance at 590 nm (Figure2). All spectral measurements have been passed out against double distilled water as the reagent blank which gives negligible absorbance at this wavelength. The coloured system obeys Beer’s law in the range of 0.5-5.0 g (Figure3). The molar absorptivity and Sandell’s sensitivity of the violet colour dye are given in the (Table1).

Table 1. Spectral characteristics and statistical data

Optimization of Chemical reaction

It was found that 0.5 mL each of bromine water and mixture of potassium iodide and potassium iodate and 1-2 drops of formic acid and 0.5 mL leucocrystal violet solution was satisfactory for complete the reaction (Figure 4 and 5). When amount of reagent was used in less and high amount deviation in absorbance value was observed. Reaction was conducted at temperature among the vary of 20-30^oC. Reaction was stable at 4 pH (Figure 6) Dye was stable for several days, when the colour had developed. Effect of other species and ions was studied and their tolerance limit values are given in (Table 2). To validate the proposed method in soil, water and some vegetable samples were taken and spiked with 10 g mL^-1 of mycobutanil followed by proposed method to obtained recovery of the total mycobutanil have given in (Table 3).

Figure 6. Effect of pH on complex formation

Table 2.  Effect of foreign species and ions with their tolerance limit

Table 3. Determination of mycobutanil in various environmental and agricultural samples

Analytical Applications

Determination of Myclobutanil in polluted water

Water sample from pond near agricultural field were collected. This sample was extracted with 2 × 25 mL portion of diethyl ether. The ether solution was evaporated to dryness, and the residue was dissolved in 50 mL of water. Aliquots were then examined as proposed above method.

Determination of Myclobutanil in soil sample

Soil sample 5g was taken in an Erlenmeyer flask of 250mL. 20mL of 0.3% sulfuric acid was added to this flask along with 10mL of 6% m/v hydrogen peroxide plus glycerin 0.5mL. The obtained mixture is boiled at 160-180^oC for 20min on a sand – bath, then again add 2mL of hydrogen peroxide and further boil it for 10min more. After this bring the mixture to room temperature and add 50mL of deionized water and analyzed as proposed method.

Determination of Myclobutanil in Different Fruits and Vegetable samples

Different fruits and vegetable samples were weighed, mashed along with acetone de-ionized water (1:1) and then strained and passed from thin cotton cloth. The strained solution is then preceded with centrifugation at 1850 rpm for 10 min. Then 10mL of sample aliquot were treated with proposed method.

Conclusion

This proposed method is found to be simple, sensitive, and rapid spectrophotometric method for the analysis of Myclobutanil. Also, it used less toxic substance as reagents for the analysis. This method can be considered as one of the good alternative to most of the high costing, delicate apparatus which need much more in maintenance. It can be very efficiently applied for the determination of Myclobutanil in water, fruits and vegetables samples, which is yet not been determined with spectrophotometer.

Acknowledgement

Authors are thankful to Head of department School of Studies in chemistry Pt. Ravishankar Shukla University Raipur and Director General Chhattisgarh Council of Science and Technology Raipur for grant and providing lab facility.

References

Easwari, S., Jayakumar, R. (2017). Detection of Methyl Parathion Residues in Vegetables by using chromogenic reagents, Internation Journal of Current Microbiology and Applied Science, 6(12), 711-718.

Han, W., Wang, Y., Gao, J., Shijie, W., Zhao, S., Liu, J., Zhong, Y., Zhao, D. (2017),  Acute toxicity and sublethal effects of myclobutanil on respiration, flight and detoxification enzymes in Apis cerana cerana, Pesticides Biochemistry and  Physiology, 23, 56-64.

Kim, H, K.; Kabir, E.; Jahan, A, S. (2017). Exposure to pesticides and the associated human health effects, Science of the Total Environment., 575, 525-535.

Lin, C., Zhang, L., Zhang, H., Wang, Q., Zhu, J., Wang, J., Qian, (2018). Enantioselective degradation of Myclobutanil and Famoxadone in grape, Environmental Science and Pollution Researh, 25: (3), 2718-2725.

Mohamed, M., Megeed, M., Hammad, A. (2017). Cytotoxicity of imidacloprid and myclobutanil pesticides on three cancer cell lines. Arab University Journal of Agricultural Science, 25(2), 331-338.

Mostafalou, S.; Abdollahi, M. 2017. Pesticides: an update of human exposure and toxicity, Archives of Toxicology, 91(2), 549-599.

Na, L., Yang, L. Z., Xue, D., Feng, X. B., Lan, C. L. (2017). Selective bioactivity of enantiomers of three triazole fungicides against Fusarium spp, Journal of University of Science and Technology of China. 38 (5), 56-60.

Nirmal.M., Mundeja, P., Wani, K., Patel, V., Khatoon, R., Sahu, A.K., Sahu, D.K., Rai, M.K., Rai, J.K. and Michael,P., (2018), Assessment of fenvalerate in water, soil and vegetable samples, Journal of Ravishankar University-B, 30(1&2), 60-65.

Suyal, A., Shrivastava, A., (2016). Dissipation and Bioefficacy Studies of Myclobutanil in Chilli under Tarai Region of Uttarakhand, India, Asian Journal of Chemistry, 28(12), 2661-2664.

Yan, B., Li, J., Li, Y, H., Gao, J., Wang, A, M., Ren, Y, G., Ma, H, X., (2016). Crystal structure and thermodynamic properties of Myclobutanil, The Journal of Chemical Thermodynamics, 101, 44-48.

Zhang, L., Dong, X., Wong, C., Zou, Z., Chen, M. (2017). Bioaccumulation and the expression of hepatic cytochrome P450 genes in marine medaka (Oryzias melastigma) exposed to difenoconazole, Journal of Environmental Sciences, 52, 98-104.

Zhang, Y., Zhang, Y., Zhao, Q., Chen, W., Jiao, B. (2016). Vortex-Assisted Ionic Liquid Dispersive Liquid-Liquid Microextraction Coupled with High-Performance Liquid Chromatography for the Determination of Triazole Fungicides in Fruit Juices, Food Analytical Methods, 9(3), 596-604.