Purity analysis of carbofuran used in tomato (solanum lycopersicum l.) In Bangladesh

Purity analysis of carbofuran used in tomato (solanum lycopersicum l.) In Bangladesh
Mohammed Ariful Islam 1, Abdullah- Al- Numan2, Md. Mahmudul Hasan Khan*3, Razi Uddin4, Gazi Nazmul Hasan 4, Md. Mahbubur Rahman4, Mohammad Sarfuddin  Bhuiyan5
1Professor, Department of Agricultural Chemistry, Sher-e-bangla Agricultural University, Bangladesh
2MSc, Department of Agricultural Chemistry, Sher-e-bangla Agricultural University, Bangladesh
3* Scientific Officer, Plant Breeding,  Bangladesh Agricultural Research Institute,  Bangladesh.
4 Scientific Officer, OFRD, Bangladesh Agricultural Research Institute, Bangladesh.
5 Senior Scientific Officer, OFRD, Bangladesh Agricultural Research Institute, Bangladesh.
Received Date: 27th August, 2018 Accepted Date: 29th August, 2018; Published Date: 3rd September, 2018
*Correspondence: Md. Mahmudul Hasan, Scientific Officer, Plant Breeding,  Bangladesh Agricultural Research Institute,  Bangladesh; E-mail: jiwubapc@gmail.com or jiwubapc@gail.com
Citation: MD. I. Ariful, AL AN, Md. Khan MH,  R Uddin, GN Hasan, Md. M Rahman, MS Bhuiyan (2018 Purity analysis of carbofuran used in tomato (solanum lycopersicum l.) In Bangladesh. Adv in Nutr Fd Sci: ANAFS-108.


Abstract

The aim of the present study was to conduct purity analysis of carbofuran, a frequently used pesticide by the farmers in tomato field. All the pesticides available in the markets were found as authorized pesticides and none of them were found to be extremely hazardous according to the WHO recommended classification except carbofuran. Therefore to find out present quality status of carbofuran (5G) products available in market, purity analysis of randomly chosen thirteen samples was done by GC-FID. Among them the highest concentration was found 6.82%. No carbofuran content was found in two samples. Most accurate concentration was 5.04%. The present study indicates that there is a high chance to have residual effects of pesticides in tomato as a result of preharvest or postharvest application. Most of the farmers do not know about health risk issue of using agro-chemicals. In case of purity analysis of Carbofuran, approximately 46% samples showed overconcentration, 30% showed below concentration and two samples showed no concentration of Active ingredient (AI). This variation in results indicates the reason why farmers tend to go with non-judicial application of pesticides. The level of pesticide residues in tomato is affected by washing, preparatory steps, heating or cooking, processing during product manufacturing and post-harvest handling and storage.  It is important to aware the farmers to follow the recommended dose of registered pesticides and the consumers to proper handling and processing of tomato for safe consumption. Information on health risk, exposure assessment was also highlighted for public awareness. Suggestions were provided on the handling and processing such as washing, cooking, boiling, packing, storage etc. for the safety of the consumers.


Rough:

  • 1 mg / 1 L (1000 mL) = 1 ppm
  • 5 mg / 50 mL

= (18.5 mg x 20) x (50 mL x 20)
= 370 mg / 1000 mL
= 370 ppm

Working Standard preparation:

0 ppm, 25 ppm, 50 ppm, 75 ppm & 100 ppm carbofuran solution were prepared by using the following table: Table 1.

Concentration (ppm) Stock solution (mL) Acetonitrile (mL) Total (mL)
0 0 10 10
25 0.676 9.324 10
50 1.351 8.649 10
75 2.027 7.973 10
100 2.703 7.297 10

Table 1: Preparation of Standard Solution

Rough: V1 x S1 = V2 x S2Where,
V1 = Required volume?
S1 = Conc. of stock solution
V2 = Final Volume

Sample Preparation: Take 100 mg of Carbofuran sample in 10mL volumetric flask. Dilute it with acetonitrile and vortex for 1hour (500 ppm). Take 1 mL of above sample in 10 mL Falcon tube then dilute it with acetonitrile (50 ppm).

Rough: 5G means 5%
5% means 5 g Carbofuran active is present in 100 g sample
100 mg in 10 mL = 500 ppm (Since 5 mg active in 100 mg sample)

  • Chromatographic Condition:
  • Column: Rtx-624, 0.25mmID, thickness-1.4um, length-30m
  • Detector: FID (Flame Ionization Detector)
  • SPL (Injection Port) Temperature: 2300C
  • Detector Temperature: 2400C
Rate Temp         Hold time
 

10

1000C

2000C

3

2

 

Table 2: Column (Column Oven Temperature Program)

Total time program – 15.00 min
Split Ratio: 5
Column flow: 2.5 ml/min.
Retention Time: 12.49 minute.
For safety measurement, various recommended suggestions regarding safe handling and processing were also considered.


Result And Discussion
Purity Analysis Result of Carbofuran: Thirteen Marketed brands of Carbofuran 5G were tested with GC-FID. The analysis result for the purity testing of the formulated brands has been summarized in the following (Table 1).

Code no. Formulation type Amount of AI present (%)
Cf1 5G 5.44
Cf2 5G 3.02
Cf3 5G 5.76
Cf4 5G 6.74
Cf5 5G 5.38
Cf6 5G 4.46
Cf7 5G 5.70
Cf8 5G 4.36
Cf9 5G 2.84
Cf10 5G 5.04
Cf11 5G 0
Cf12 5G 0
Cf13 5G 6.82

 

Table 1: Percentage of active ingredient presents in thirteen marketed brands of carbofuran 5G.

Figure 1: Purity percentage of carbofuran samples.

       Results reveal that only Cf10 was almost 100% pure in term of AI presence. No result was found in case of Cf11 and Cf12. 50%-60% purity was shown by Cf2 and Cf9.  Over concentration of AI was shown by Cf3, Cf4 and Cf13 (Figure 1).


Mitigation Process of Pesticide Residue for Safe Consumption
Effect of handling and processing: Foods after harvest/slaughter are subjected to various handling and processing operations both at home or industry level, involving a simple washing to more multi-step and complex processing aimed to extend shelf-life, add variety, increase palatability and nutrient availability and to generate income. The various techniques and methods applied usually reduce residue levels because of washing or cleaning, peeling, blanching, juicing, cooking, milling baking, pasteurization, canning etc. Thus there is an increasing need for information about the effects of various processes on the fate of pesticide residues in foods both from a regulatory and public concern perspective. The available information has been elaborated under the following heads:

Preparatory steps: The extent of pesticide reduction depends upon the washing operations, nature of pesticide molecule and other preparatory steps used. Loosely held residues of several pesticides are removed with reasonable efficiency by varied type of washing processes [12]. Moreover, majority of pesticides applied to crops are confined to the outer surfaces and undergo limited movement or penetration of the cuticle. Therefore, they are amenable to removal by washing, peeling and trimming operations [13]. The effect of different preparatory steps on pesticide residues in food is being described under various subheads.
Washing with water: Fruits and vegetables are invariably washed before consumption. Vegetables are often peeled off and cooked prior to eating. Bindra [14] reported 80–83% reduction of carbaryl by washing of tomato. However, only 18–55% endosulfan was reduced by washing.  Removal of the fruit stalk, exocarp and tissue around stalk cavity of fruits and fruit-type vegetables and washing of leaves with water or dilute detergent solution were necessary to decrease the intake of pesticide residues from vegetables and fruits. In case of tomato, Singh and Lal [15] reported a reduction of 86.20% in malathion deposit by one minute washing only. It was found that washing of tomato fruits in a stream of water for 1–3 h reduced pesticide residues in tomato products; tomato seeds showed higher levels of residues as they were not subjected to processing [16]. The effectiveness of washing was, however, reduced at later stages of all the insecticides and more specifically on synthetic pyrethroids due to strong bonding between the insecticide molecules and waxy layer of fruit skin and also their non-systemic and non-translaminar movement characteristics [17], [18].
Washing with salt solution: Washing with dilute salt (sodium chloride) solution is a convenient method to lower the load of contaminants from food surfaces particularly fruits and vegetables. This method could be equally effective for reducing the pesticide residue from other commodities too. This procedure is recommended as being practical for household use [17], [18].
Washing with chemical solutions: Chlorine water and dilute solutions of other chemicals are commonly used for disinfection of fruits and vegetables. These chemicals play an effective role in removing the pesticide residues. The results of  Wu [19] on the degradation of four pesticides by low concentration of dissolved ozone indicated that initial concentration of 1.4 ppm was effective to oxidize 60–99% of 0.1 ppm aqueous diazinon, parathion, methyl-parathion and cypermethrin shortly within 30 min. Ozonated water was mostly effective in cypermethrin removal (>60%). The efficacy highly depended on the dissolved ozone levels. Higher temperature enhanced the efficacy in pesticide removal with maximal efficacy for diazinon removal detected at 15–20 °C.
Kitchen type and combination processing: Peeling was found to be the most effective way to remove the pesticide from the vegetables followed by frying. Boiling was effective in reducing the level of water-soluble pesticides [20],[21] found that plain washing dislodged 20–52% mancozeb residues while washing coupled with cooking led to 53–79% decontamination on cabbage, knoll-khol, tomato, okra and brinjal. Cooking did not help much in reducing the residue below the MRLs of 0.25 and 0.05 ppm for quinalphos and chlorpyriphos respectively.  Kadian [22] reported that cypermethrin residues declined in tomato, okra, bottle gourd and ridge gourd after all processing steps i.e. about 5–14% by washing, 6–26% by blanching, 6–19% by washing in brine solution and 15–33% by cooking. Lee and Lee (1997) revealed that 45% of organophosphorous pesticide (OP) residues were eliminated when foods were washed in water, 56% with detergent washing, 91% with peeling, 51% with blanching-boiling and 90% in milling and processing. In tomato both the washing and cooking reduced the residues almost to the same extent of 11–30% [23].
Thermal Treatment: Foods are invariably subjected to heat treatment during preparation and preservation. The heat treatment is given in many ways including pasteurization, boiling, cooking etc. depending upon the nature of food and aim of processing. The loss of pesticide residue during heat processing may be due to evaporation, co-distillation., thermal degradation which vary with the chemical nature of the individual pesticide [24].
Cooking/boiling/Steaming : Incidence and stability of pesticide residues in some vegetable and fruits as affected by food processing was studied by El-Nabarawy [25]. Processing such as cooking caused marked reduction in insecticides, resulting in complete removal of insecticide residues in some cases.
Product manufacture:  A set of processing techniques are used to convert raw materials into a variety of products for consumption. The amount of residue in the final product may be reduced or enhanced depending upon a set of parameters employed and length of processing. In addition, micro-organisms/fermentation, if employed, also contribute to residual degradation of pesticides [24].
Drying and dehydration: The drying process could cause an appreciable decline in pesticide residues mainly due to evaporation, degradation and codistillation.The different drying methods have different effect on different pesticides In the production of raisin, the sun drying process caused a 4 times concentration of residue level while oven drying which was preceded by washing lead to decrease in iprodione and procymidone [26].
Canning of fruits and vegetables: In most cases, operations leading to canning resulted in a gradual decrease in residue levels in the finished products; the washing, blanching, peeling and cooking stages were particularly effective. Ethylenebisdithiocarbamates were completely removed from tomatoes and spinach by washing followed by hot water blanching. Samples analyzed at each stage of industrial processing of tomato showed a progressive reduction in the contents of the 3 insecticides, only insignificant quantities of dimethoate remaining after the pasteurization stage [27].
Juice/concentrate preparation: The distribution of 9 pesticides between the juice and pulp of carrots and tomatoes during home culinary practices was investigated by Burchat [26]. Tomato and carrot pulp contained a higher percentage of all pesticide residues, except for mancozeb in tomato juice. Although there was a difference in the relative distribution of the pesticides between the commodities with greater amounts present in the pulp of tomatoes, the pesticides followed a similar trend in both. Pesticides with the highest water solubility were present to a greater extent in the juice. An exception was noted in the case of diazinon and parathion, which were present in higher amounts in the pulp than their water solubility suggested. The residue in the pulp ranged from 56.4 to 75.2% for carrots and 49.7 to 95.4% for tomatoes. Washing of the produce removed more residues from carrots than from tomatoes, but it did not affect the relative distribution of the residues. The behavior and fate of the chemical varied with the pesticide as well as the crop. Pesticide residues were greatly decreased in tomato juice under cold or hot break. A sharp decline in profenofos level was noted after treatment by pectinex ultra SP-L and benzyme M during tomato crushing [28].


Postharvest handling
Packing: The packing process before shipment to retail outlets was generally effective in removing pesticides that may be present on peel at the time of harvest.
Storage: Gill [23] sprayed brinjals and tomatoes with alphamethrin and stored at ambient (40 °C) and refrigerated conditions (5 °C). Dissipation of alphamethrin was observed faster at room temperature as compared to cold conditions in both the vegetables.


Conclusion
      Results of purity analysis of Carbofuran revealed that only Cf10 was almost 100% pure in term of AI presence. No result was found in case of Cf11 and Cf12. 50%-60% purity was shown by Cf2 and Cf9.  Over concentration of AI was shown by Cf3, Cf4 and Cf13. In case of purity analysis of Carbofuran, approximately 46% samples showed overconcentration, 30% showed below concentration and two samples showed no concentration of Active ingredient (AI). This variation in results indicates the reason why farmers tend to go with non-judicial application of pesticides. The level of pesticide residues in tomato is affected by washing, preparatory steps, heating or cooking, processing during product manufacturing and post-harvest handling and storage.


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