Imidazolinone herbicides are extensively used in recent years to control the growth of weeds in rice field area and improve its productivity. The herbicide used in the rice field is the combination of imazapyr (17.5%) and imazapic (52.5%) from the imidazolinone family plus inert ingredient (30%). Its persistence in soil media may pose severe ecological and human impacts through drifting or leaching. Since dietary intake is the main route for human exposure, fish can be the main contributor to the herbicide intake in human beings. Several studies have demonstrated a clear correlation between the frequency of fish consumption and the level of contaminant in human tissues, serum and milk.
In general, the determination of these herbicides in fish involves extraction of the analytes, removal of co-extracted lipids, concentration and chromatographic analysis. The most crucial steps are the extraction of target analytes from the bulk of the matrix and clean-up of the analytes from the matrix co-extractives. To date several extraction techniques have been applied such as liquid-liquid extraction (LLE), solid-liquid extraction (SLE), Soxhlet extraction (SE), matrix solid-phase dispersion (MSPD), microwave assisted extraction (MAE), ultrasonic assisted extraction, pressurized liquid extraction (PLE), supercritical fluid extraction (SFE) and accelerated solvent extraction (ASE).
Another extraction method of interest is solid phase extraction (SPE) techniques which is capable of extracting the polar compounds like the imidazolinone herbicide. SPE technique have been proven successful to determine imazapyr, imazathapyr, imazaquin, imazamox in water and soil media only. However, to our knowledge, no extraction method has been fully developed for determination of imidazolinone herbicide either individually or simultaneously in biological samples.
This study aims to evaluate the efficiency of different solvents for extraction of imazapyr and imazapic residues using different types of SPE cartridges for the extraction and clean-up procedure prior to analysis by high performance chromatography (HPLC). Recoveries experiments would be conducted to confirm the validity of the methods. Findings from this study would allow us to propose an efficient extraction procedure for selected imidazolinone herbicides in fish samples.
The rice productivity level in Malaysia is high, approaching 2, 464, 830 tonnes matrix of paddy crop in 2010 (Department of Agriculture, 2012) and contribute nearly 60 percent of the country’s annual rice consumption (Ismail et al., 2011). However, the presence of weedy rice led to the decrease of rice production in Malaysia (Fuad et al., 2012). To overcome the problem, combination of imazapyr and imazapic from the imidazolinone family was introduced to control the weeds (Rohaniza, 2010; Azmi et al., 2012).
The herbicide control the weeds by inhibiting the enzyme acetohydroxyacid synthase (AHAS) which is important for...