Dissipation Rate of Different Commercial Formulations Of

Arabian Journal of Chemistry (2016) 9, S1402–S1405

King Saud University Arabian Journal of Chemistry

www.ksu.edu.sa www.sciencedirect.com

ORIGINAL ARTICLE Dissipation rate of diﬀerent commercial formulations of propamocarb-hydrochloride applied to potatoes using HPLC–DAD

Sherif H. Abd-Alrahman a,b,*, M.M. Almaz a a Pesticides Residues and Environmental Pollution Dept., Central Agricultural Pesticides Laboratory, Agricultural Research Center, Giza 12618, Egypt b Biochemistry Department, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia

Received 4 January 2012; accepted 13 March 2012 Available online 20 March 2012

KEYWORDS Abstract Propamocarb-hydrochloride is a widely used fungicide around the world. Hence, only Dissipation; limited data are available on the fate of this fungicide. Residue levels and degradation rate of two Fungicide; different formulations propamocarb-hydrochloride (Previcur-N 72.2% SL and Proplant 72.2% Propamocarb-hydrochloride; SL) in potatoes was investigated by using high performance liquid chromatography with diode Formulation; array detector (HPLC-DAD). The experimental data were used to determine the residual behav- QuEChERS ior and establish the preharvest intervals (PHI). Samples were prepared using QuEChERS methodology before quantiﬁcation by high performance liquid chromatography with diode array detector (HPLC–DAD). Field trials showed a different degradation rate for two studied formulations. The initial deposit of 0.99 and 1.31 mg kgÀ1 for Previcur-N and Proplant, respectively after 10 days of application degraded to 0.02 mg kgÀ1 (97.98%) and 0.32 mg kgÀ1 (75.57%)

and the half-lives (t1/2) were 2.26 and 6.29 days, respectively. We suggested that a waiting period of at least 3 and 10 days before harvesting the potatoes after application of two studied formulations that may be considered quite safe from point of health hazards due to the toxic effect of residues. ª 2012 Production and hosting by Elsevier B.V. on behalf of King Saud University. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/).

1. Introduction

* Corresponding author at: Biochemistry Department, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Agricultural pesticides cause increasing concerns because of Arabia. Tel.: +966 561776615. their adverse effects on human health as these residues in E-mail address: [email protected] (S.H. Abd-Alrahman). varying levels accumulate in agricultural products such as Peer review under responsibility of King Saud University. vegetables and fruits. Propamocarb hydrochloride [propyl 3-(dimethyl- amino)propylcarbamate hydrochloride, a systemic carbamated fungicide with protective action against phyco-mycetous Production and hosting by Elsevier diseases (Phythium, Phytophthora spp.) and was used http://dx.doi.org/10.1016/j.arabjc.2012.03.003 1878-5352 ª 2012 Production and hosting by Elsevier B.V. on behalf of King Saud University. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/). Dissipation rate of different commercial formulations S1403 particularly against Aphanomyces, Phytophtora and Phytium (Fernandez-Alba et al., 2001). This pesticide is used on a wide variety of mainly greenhouse vegetables and fruits (Tomlin, 2000), and is registered in Egypt for application on many greenhouse-based vegetable crops. Due to intensive use of pesticides in vegetable farming, res- Figure 1 Propamocarb-hydrochloride structural formula. idues may be accumulated at higher levels than those permitted by the international MRLs. Assessment of dissipation rate of a pesticide after application is a key process for determining the 50 mL MeOH to obtain solution concentration 1 mg/mL residual behavior of pesticides in agricultural crops and for (Fig. 1). A working standard solution of 10 lgmLÀ1 was detecting pre-harvest interval (PHI). Additionally, residues dis- prepared by appropriately diluting the stock solution with sipation curves can be used to estimate the time required for MeOH. Stock solution was stored at 20 ± 2 C, and decreasing the residues below MRLs (Castillo-Sanchez et al., À working standard solutions were stored in the dark 64 C 2000; Ambrus and Lantos, 2002; Fenoll et al., 2009). when not in use. QuEChERS (quick, easy, cheap, effective, rugged and safe) is a method which has been mainly applied for the extraction 2.4. Sample preparation of different classes of pesticides (Lehotay et al., 2005; Paya et al., 2007; Garrido Frenich et al., 2008; Abd-Alrahman et al., 2011a). This method achieved the status of Official The samples were homogenized for 5 min at high speed using a Method of AOAC International (Lehotay, 2007). food processor (Thermomix, Vorwerk). The homogenate of The present study examines the behaviour of two commer- each sample was then placed into polyethylene 50 mL centri- cial formulations of propamocarb-hydrochloride on potatoes, fuge tube and stored frozen at À20 ± 2 C until further anal- and determines the pre-harvest intervals and the half-lives ysis. Samples were extracted according to the procedure in/on potatoes. described and modified by Lehotay (Lehotay et al., 2010) and validated by Sherif (Abd-Alrahman et al., 2011b). Briefly, 10 g of the homogenized sample was weighed into a 50-mL 2. Material and methods centrifuge tube. Ten milliliters of 1.0% acidified acetonitrile with acetic acid were added; closed and vigorously shaken 2.1. Chemicals for 1 min using a vortex mixer at maximum speed. Afterward, 4 g of anhydrous MgSO4, 1 g of NaCl, 1 g sodium citrate dihy- Certified reference standard of propamocarb-hydrochloride drate, and 0.5 g disodium hydrogen citrate sesquihydrate were >99% purity was obtained from central agricultural pesticides added, and then extracted by shaking vigorously using vortex laboratory (CAPL). Acetonitrile (MeCN) and methanol for 2 min following centrifugation for 10 min at 5000 rpm. An (MeOH) of HPLC grade were purchased from Merck. Bulk pri- aliquot of 3 mL was transferred from the supernatant to a new mary secondary amine (PSA) sorbent (Bondesil-PSA, 40 lm) clean 5-mL centrifuge tube and cleaned by dispersive solid- was bought from Subelco. Ammonium acetate (cryst. Extra phase extraction with 75 mg of PSA and 500 mg of magnesium pure), acetic acid and sodium chloride were purchased from sulfate. Afterward, centrifugation was carried out at 6000 rpm Merck. Magnesium sulfate anhydrous fine powder, trisodium for 5 min. An aliquot (2 mL) from the supernatant was filtered citrate dihydrate (Extra pure) and disodium hydrogencitrate through a 0.2-ı` m PTFE filter (Millipore, USA) and then sesquihydrate (Extra pure) were purchased from Merck Ltd. analyzed by Agilent 1100 HPLC–DAD.

2.2. Field experiment 2.5. Apparatus and chromatographic analysis

For the field experiment, a random block scheme was used Pesticide residue analysis was performed with Agilent technol- with three replications for each test. Propamocarb-hydrochlo- ogies HP-1100 series high-performance liquid chromato- ride was applied with a backpack motorized sprayers with an graphic system (Agilent Technologies, USA) equipped with a adjustable nozzle size of 1 mm using the two commercial for- diode array detector and quaternary pump. The separation mulations Previcur-N 72.2% SL and Proplant 72.2% SL. was performed on a C18 column (150 · 4.6 mm, 5 lm). The The pesticide application was carried out in Nov. 21th 2008, mobile phase was (MeOH/Water 70:30 v/v) with a flow rate À1 at the dose recommended by the manufacturers 250 cm3 of 0.8 mL min and detection wavelength of 260 nm Data 100 LÀ1water. Samples were collected 1 h after application analysis was performed using Chemistation software. and then after 1, 3, 5, 7, 10 and 15 days. A control sample was also taken at each sampling time. Immediately after col- 2.6. Statistical analysis lecting the samples, each individual sample was put into plastic bags and transported to the laboratory. Data were statistically evaluated by one-way analysis of vari- ance (ANOVA). Determination of the differences among 2.3. Standard preparation means was carried out by using the least significant differences (LSD) test. All statistical analyses were done using the Statistical Package for social sciences (SPSS 16.0) Stock solution of propamocarb-hydrochloride was prepared program. by dissolving 50 mg of the analyte (of accurate weight) in S1404 S.H. Abd-Alrahman, M.M. Almaz

3. Results and discussion a b

3.1. Method performance

Control (without pesticide application) samples of potatoes were used for the evaluation of selectivity. The absence of any signal at the retention time of propamocarb-hydrochloride indicated that no matrix compounds are present, which could give false positive signal. The calibration curve of propamocarb-hydrochloride showed a good linearity and strong corre- lation between concentrations and area in the studied range (0–100 ng mLÀ1)(r2 P 0.996). A recovery of propamocarb- Figure 2 Dissipation curve of two different formulations of hydrochloride from potatoes was 87.8 % ranged from 85.5 propamocarb-hydrochloride in/on potatoes (a) Previcur-N 72.2% to 90.1 %, Table 1. Precision was studied by performing SL and (b) Proplant 72.2% SL. repeatability studies, expressed as RSD. Satisfactory precision was obtained for propamocarb-hydrochloride. Repeatability was lower than 7% for all three levels assayed. Similarly, with for Previcur-N and Proplant, respectively. A similar behavior the examination of the matrix effect, a general tendency was of iprodione and thiacloprid residue levels was observed by observed toward higher values of RSDs at low spiking concen- (Omirou et al., 2009), Mean residue levels of both pesticides trations. Instrumental LOD based on S/N of 3:1 and LOQ were below the EU established MRLs throughout the experi- based on S/N of 10:1 was (0.9 and 2.7 lgkgÀ1). mental period. Also Omirou reported that the highest residue levels in both treatments were determined in samples taken in the ﬁrst sampling just after pesticide application as in our 3.2. Residual behavior of propamocarb-hydrochloride case. In another study by Beouwer was reported that the dissipation of pesticide deposit was a complex process depending Propamocarb-hydrochloride mean residue levels during the on the various environmental factors like temperature, relative sampling period for each application derived from three sub humidity and UV irradiation, metabolism and translocation samples are shown in (Table 1 and Fig. 2). Residue levels of (pesticide penetration and plant growth), application tech- propamocarb-hydrochloride were found to be below the nique and pesticide formulation (McCrady and Maggard, À1 MRLs established by the Codex Committee (0.5 mg kg ) 1993; Brouwer et al., 1997; Katagi, 2004). after the application of recommended dose, which were 250 cm3 100 LÀ1 water for potatoes, throughout the experi- 4. Conclusions mental period (FAO/WHO 2006). The highest residue levels were found in samples taken in the ﬁrst sampling time 1 h after pesticide application. The highest Dissipation rates of two commercial formulations of prop- mean concentration of propamocarb-hydrochloride residue amocarb hydrochloride after a single application at recom- was found in samples treated with Proplant 0.99 mg kgÀ1, mended dose on potatoes were evaluated. An optimized followed by Previcur-N 1.31 mg kgÀ1, residue levels of (QuEChERS) method was used for sample preparation. propamocarb-hydrochloride had been decreasing in the follow- Through this method, we achieved a good analytical perfor- À1 ing period, reaching levels 0.02 and 0.32 mg kgÀ1 in 10 days mance in terms of sensitivity (LODs, 0.5–1.2 lgkg ; LOQs, À1 after application for Previcur-N and Proplant, respectively. 2.3–4.5 lgkg ) and recovery rates (84.8–90.1%). Thus, this method can be used for residue determination in the detec- The results showed different half-life(s) (t1/2) and PHI for propamocarb-hydrochloride of (2.26, 3) and (6.29, 10) days tion of propamocarb-hydrochloride residues with low levels.

Table 1 Dissipation of two different formulations of propamocarb-hydrochloride in/on potatoes. Time (Days) Previcur-N 72.2 % SL Proplant 72.2 % SL Residue level (mg/kg) Mean ± SD Loss % Residue level (mg/kg) Mean ± SD Loss % Initial 0.00 0.00 0.00 0.00 1 0.99 ± 0.09 0.00 1.31 ± 0.08 0.00 3 0.48 ± 0.06 51.52 1.09 ± 0.06 16.79 5 0.28 ± 0.05 71.72 0.89 ± 0.10 32.06 7 0.11 ± 0.06 88.88 0.65 ± 0.05 50.38 10 0.02 ± 0.05 97.98 0.32 ± 0.04 75.57 15 nd - 0.1 ± 0.06 92.37 Mean recovery % 87.8 (85.5-90.1) MRL (mg/kg) 0.5 t1/2 (day) 2.26 6.29 PHI (day) 3 10 r2 0.991 0.986 Initial : 1 hour post treatment. nd : not detected. Dissipation rate of different commercial formulations S1405

Propamocarb-hydrochloride has shown different dissipation Katagi, T., 2004. Photodegradation of pesticides on plant and soil rates: half-life(s) and PHI for two different formulations were surfaces. Rev. Environ. Contam. Toxicol. 182, 1–189. applied to potatoes. Our results indicate that the dissipation Lehotay, S.J., 2007. Determination of pesticide residues in foods by rate might be affected by the difference of commercial acetonitrile extraction and partitioning with magnesium sulfate: collaborative study. J. AOAC Int. 90, 485–520. formulations. However, the long PHIs might lead to a higher Lehotay, S.J., de Kok, A., Hiemstra, M., Van Bodegraven, P., 2005. risk of exposure to propamocarb-hydrochloride, especially in Validation of a fast and easy method for the determination of case of proplant formulation. residues from 229 pesticides in fruits and vegetables using gas and liquid chromatography and mass spectrometric detection. J. AOAC References Int. 88, 595–614. Lehotay, S.J., Son, K.A., Kwon, H., Koesukwiwat, U., Fu, W., Abd-Alrahman, S.H., Almaz, M.M., Ahmed, N.S., 2011a. Dissipation Mastovska, K., Hoh, E., Leepipatpiboon, N., 2010. Comparison of of fungicides, insecticides, and acaricide in tomato using HPLC– QuEChERS sample preparation methods for the analysis of DAD and QuEChERS methodology. Food Anal. Methods. http:// pesticide residues in fruits and vegetables. J. Chromatogr. A dx.doi.org/10.1007/s12161-011-9279-0. 1217, 2548–2560. Abd-Alrahman, S.H., Almaz, M.M., Osama, I.A., 2011b. Determina- McCrady, J.K., Maggard, S.P., 1993. Uptake and photodegradation tion of degradation rate of acaricide fenpyroximate in apple, citrus, of 2,3,7,8-tetrachlorodibenzo-p-dioxin sorbed to grass foliage. Env. and grape by HPLC–DAD. Food Anal. Methods. http:// Sci. Technol. 27, 343–350. dx.doi.org/10.1007/s12161-011-9243-z. Omirou, M., Vryzas, Z., Papadopoulou-Mourkidou, E., Economou, Ambrus, A., Lantos, J., 2002. Evaluation of the studies on decline of A., 2009. Dissipation rates of iprodione and thiacloprid during pesticide residues. J. Agric. Food Chem. 50, 4846–4851. tomato production in greenhouse. Food Chem. 116, 499–504. Brouwer, D.H., de Haan, M., Leenheers, L.H., de Vreede, S.A., van Paya, P., Anastassiades, M., Mack, D., Sigalova, I., Tasdelen, B., Hemmen, J.J., 1997. Half-lives of pesticides on greenhouse crops. Oliva, J., Barba, A., 2007. Analysis of pesticide residues using the Bull. Environ. Contam. Toxicol. 58, 976–984. Quick Easy Cheap Effective Rugged and Safe (QuEChERS) Castillo-Sanchez, J., Aguilera-Del Real, A., Rodriguez-Sanchez, M., pesticide multiresidue method in combination with gas and liquid Valverde-Garcia, A., 2000. Residue levels, decline curves, and chromatography and tandem mass spectrometric detection. Anal. plantation distribution of procymidone in green beans grown in Bioanal. Chem. 389, 1697–1714. greenhouse. J. Agric. Food Chem. 48, 2991–2994. Tomlin, C.D.S., 2000. The Pesticide Manual, twelvth ed. British Crop Fenoll, J., Ruiz, E., Hellı´n, P., Lacasa, A., Flores, P., 2009. Dissipation Protection Council, 643, pp. 769–770. rates of insecticides and fungicides in peppers grown in greenhouse and under cold storage conditions. Food Chem. 113, 727–732. Further reading Fernandez-Alba, A.R., Guil, L.H., Lopez, G.D., Chisti, Y., 2001. Toxicity of pesticides in wastewater: a comparative assessment of US-EPA, 2011. Propamocarb-hydrochloride Human-health Assess- rapid bioassays. Anal. Chim. Acta 426, 289–301. ment Scoping Document in Support of Registration Review. Garrido Frenich, A., Martinez Vidal, J.L., Pastor-Montoro, E., Washington, D.C. 20460. Romero-Gonzalez, R., 2008. High-throughput determination of pesticide residues in food commodities by use of ultra-performance liquid chromatography-tandem mass spectrometry. Anal. Bioanal. Chem. 390, 947–959.