Pressurized hot water extraction coupled to molecularly imprinted polymers for simultaneous extraction and clean-up of pesticides residues in edible and medicinal plants of the Okavango Delta, Botswana

Janes Mokgadi 1 , Shima Batlokwa 2 , Keta Mosepele 3 , Veronica Obuseng 4 , and Nelson Torto 1
  • 1 Department of Chemistry, Rhodes University, P O Box 94, Grahamstown, 6140, South Africa
  • 2 Department of Earth & Environmental Science (Chemistry Unit), Botswana International University of Science & Technology, P.O. Box 041, Bontleng, Gaborone, Botswana
  • 3 University of Botswana - Okavango Research Institute, Private Bag 85, Maun, Botswana
  • 4 Department of Chemistry, University of Botswana, Private Bag 00704, Gaborone, Botswana


In this study, an in-cell extraction and clean-up approach, employing pressurized hot water extraction (PHWE) coupled to a molecularly imprinted polymer (MIP) is proposed. The selectivity of PHWE was improved through the use of a chlorophyll MIP (PHWE-MIP) for the determination of organochlorine pesticides residue levels in various edible and medicinal plants of the Okavango Delta, Botswana. The PHWE-MIP method achieved simultaneous extraction and clean-up. PHWE employed an optimal temperature of 260 °C, pressure of 90 bar and flow rate of 1 mL min-1 in 10 min for the extraction of the pesticides from plants while the MIP selectively overcame the interfering chlorophyll prior to analysis with gas chromatograph coupled to electron capture detector or mass spectrometer (GC-ECD/MS). The results obtained were compared to the QuEChERS Official Method 2007:01 for pesticides residue analysis. The proposed method seems to be nearly fully automated, environmental friendly, selective, simple and quick. Moreover, the recoveries of planar pesticides were improved (93-95%) with relative standard deviations (%RSD) of less than 10%.

If the inline PDF is not rendering correctly, you can download the PDF file here.

  • [1] A.L. Chiuchiolo, R.M. Dickhut, M.A. Cochran and H.W. Ducklow, “Persistent organic pollutants at the base of the Antarctic marine food web,” Environ. Sci. Technol, 38 (2004) 3551-3557.

  • [2] J.Weinberg, Overview of POPs and need for a POPs treaty. Public forum on persistent organic pollutants- the international POPs elimination network, 1998.

  • [3] P.K. Gupta, M. Hubbard, B. Gurley and H. P. Hendrickson, “Validation of a liquid chromatography-tandem mass spectrometric assay for the quantitative determination of hydrastine and berberine in human serum”, J Pharm. Biomed. Anal, 49 (2009) 1021-1026.

  • [4] CODEX alimentarius, ( mrls/pestdes/jsp/pest_q-e.jsp)

  • [5] X. Gong, S. Qi, Y.Wang, E.B. Julia and C. Lv, “Historical contamination and sources of organochlorine pesticides in sediment cores from Quanzhou Bay, Southeast China” Marine Pollution Bulletin, 54 (2007) 1434–1440.

  • [6] C. Gonçalves, J.J. Carvalho, M.A. Azenha and M.F. Alpendurada, “Optimization of supercritical fluid extraction of pesticide residues in soil by means of central composite design and analysis by gas chromatography–tandem mass spectrometry”, J. Chromatogr. A 1110 (2006) 6-14.

  • [7] P. Suchan, J. Pulkrabová, J. Hajŝlová and V. Kocourek, “Pressurized liquid extraction in determination of polychlorinated biphenyls and organochlorine pesticides in fish samples”, Anal. Chim. Acta, 520 (2004) 193-200.

  • [8] L. Chen, L. Ding, H. Jin, D. Song, H. Zhang, J. Li, K. Zhang, Y. Wang and H. Zhang, “The determination of organochlorine pesticides based on dynamic microwave-assisted extraction coupled with on-line solid-phase extraction of highperformance liquid chromatography Anal.Chim. Acta, 589 (2007) 239-246.

  • [9] C. Gonçalves and M.F. Alpendurada, “Assessment of pesticide contamination in soil samples from an intensive horticulture area, using ultrasonic extraction and gas chromatography–mass spectrometry”, Talanta, 65 (2005) 1179-1189.

  • [10] S. Babić, M. Pertrović, M. Kaštelan-Macan, Ultrasonic solvent extraction of pesticides from soil, J. Chromatogr. A 823 (1998) 3-9.

  • [11] C.C. Teo, S.N. Tan, J.W.H. Yong, C.S. Hew, E.S. Ong, Pressurized hot water extraction, J. of Chromatogra. A 1217 16 (2010) 2484–2494.

  • [12] M. Anastassiades and S. J. Lehotay, “Fast and Easy Multiresidue Method Employment Acetonitrile Extraction/ Partitioning and “Dispersive Solid-Phase Extraction” for the Determination of Pesticide Residues in Produce”, J. AOAC Int., 86 (2003) 412- 431.

  • [13] A. Hubert, K.Wenzel, M. Manz, L.Weissflog,W. Engewald and G. Schüürmann, High extraction Efficiency for POPs in Real Contaminated Soil Samples Using Accelerated Solvent Extraction, Anal. Chem. 72 (2000) 1294-1300.

  • [14] Z. Sharif, Y.B.C. Man, N.S.A. Hamid, C.C. Keat, Determination of organochlorine and pyrethroid pesticides in fruit and vegetables using solid phase extraction clean-up cartridges, J. Chromatogr. A 1127 (2006) 254-261.

  • [15] A.B. Vega, A.G. Frenich, J.L.M. Vidal, Monitoring of pesticides in agricultural water and soil samples from Andalusia by liquid chromatography coupled to mass spectrometry, Anal. Chim. Acta 538 (2005) 117-127.

  • [16] M. Anastassiades, S.J. Lehotay, D. Stajnbaher, F.J. Schenck, Fast and easy multiresidue method employing acetonitrile extraction/partitioning and “dispersive solidphase extraction” for the determination of pesticide residues in produce, J AOAC Int 86 (2003) 412-431.

  • [17] S. J. Lehotay, K. Mastovska, A.R. Lightfield, Use of buffering and other means to improve results of problematic pesticides in a fast and easy method for residue analysis of fruits and vegetables, J. AOAC Int., 88 (2005) 615-629.

  • [18] M. Barriada-Pereira, M.J. González-Castro, S. Muniategui-Lorenzo, P. López-Mahía, D. Prada- Rodríguez, E. Fernández-Fernández, Determination of 21 organochlorine pesticides in tree leaves using solid-phase extraction clean-up cartridges, J. Chromatogr. A 1061 (2004) 133-139.

  • [19] Sellergren B (2001) In: Sellergren (ed) Molecularly imprinted polymers. Man made mimics of antibodies and their applications in analytical chemistry B, Elsevier, Amsterdam, pp 305–322

  • [20] E. Concha-Gra˜na, M.I. Turnes-Carou, S. Muniategui- Lorenzo, P. López-Mahía, E. Fernández-Fernández, D. Prada-Rodríguez, Development of pressurized liquid extraction and cleanup procedures for determination of organochlorine pesticides in soils, J. Chromatogr. A 1047 (2004) 147-155.

  • [21] C. Baggiani, L. Anfossi L, C. Giovannoli Molecular imprinted polymers as synthetic receptors for the analysis of mycoand phyco-toxins, Analyst 133 (2008) 719–730

  • [22] B.S Batlokwa, J. Mokgadi, T. Nyokong and N. Torto, Optimal Template removal from Molecularly Imprinted Polymers by Pressurized Hot Water Extraction, Chromatographia 73 (2011) 589–593

  • [23] D. Adeyemi, J. Mokgadi, J. Darkwa. C. Anyakora, G. Ukpo, C. Turner, N. Torto, Electrospun nanofibers sorbents for pre-concentration of 1,1-dichloro-2,2 bis- (4-chlorophenyl)ethylene with subsequent desorption by pressurized hot water extraction, Chromatographia 73 (2011) 1015–1020

  • [24] B.S Batlokwa, J. Mokgadi, R. Majors, C. N. Torto, A Novel Molecularly Imprinted Polymer for the Selective Removal of Chlorophyll from Heavily Pigmented Green Plant Extracts prior to Instrumental Analysis, Hindawi Publishing Corporation, Journal of Chemistry, Volume 2013, Article ID 540240, 4 pages,http://dx.doi. org/10.1155/2013/540240

  • [25] L.Mmualefe, Sample preparation for pesticide analysis in water and sediments: A case study of the Okavango Delta, Botswana, Doctoral Thesis, Rhodes University, 2010.

  • [26] L.C. Mmualefe N. Torto, P. Huntsman-Mapila, B. Mbongwe, Headspace solid phase microextraction in the determination of pesticides in water samples from the Okavango Delta with gas chromatography-electron capture detection and time-offlight mass spectrometry Microchemical Journal 91(2009) 239-244.

  • [27] P.S. Daka, V.C. Obuseng, N. Torto, P. Huntsman-Mapila, Deltamethrin in sediment samples of the Okavango Delta, Botswana, Water SA 32 (2006) 483-488.

  • [28] M.L.H. Mabaso, B. Sharp, C. Lengeler, Historical review of malarial control in southern African with emphasis on the use of indoor residual house-spraying, Trop. Med. Int. Health 9 (2004) 846-856.

  • [29] ASE.pdf.


Journal + Issues