A Pressurized Liquid Extraction (PLE) method was developed by using conventional High Performance
Liquid Chromatography (HPLC). It was found that all of the PAHs have been successfully extracted with dichloromethane-acetone with high percentage recovery. A high temperature of 180°C gave the highest recovery for fluoranthene (94.4%). Meanwhile, fluorene showed the highest recovery at 150 bar, with 94.6% recovery. It is noted that there is no significant day-to-day difference in the efficiency of the developed method, with the R.S.D. values averaging at 0.02. The optimized conditions applied to the soil samples were analysed using the High Temperature High Performance Liquid Chromatography (HT-HPLC) with chromatographic conditions: Octadecylsilyl-silica (ODSsilica) column (100 mm × 4.6 mm I.D.); mobile phase acetonitrile:water 40:60 (v/v); flow rate 2.5 mL/min; temperature 70°C; UV absorbance 254 nm; injection volume 5µL.
A simple and low
cost cloud point extraction (CPE) method was developed for the determination of
tartrazine in food samples by spectrophotometry detection at a wavelength 427.5 nm. The CPE was
performed by utilizing Tween 20 and sodium carbonate (Na 2 CO 3 ) as extractant and separation
accelerator, respectively. Fac tors that influenced CPE such as surfactant and salt concentrations, pH
and temperature were optimized in the context of extracting tartrazine from aqueous media. Under an
optimal condition, the proposed CPE was applied for the determination of tartrazine in sweets and
concentrated syrup juice, which represented food samples. A CPE UV Vis method showed linear
calibration within the range of 1 12 mg L 1 of tartrazine with a regression coefficient was 0.9957 . The limit of detection (LOD) and limit of quantifi cation (LOQ) of the method were 0.88 mg L 1 and 2.96
mg L 1 , respectively. The relative standard deviation (RSD) was found to be < 3.00 %. The amount of tartrazine found in food samples was 1.22 6.12 mg L 1 . The results showed that the proposed CPE
method was applicable for the determination of tartrazine in food samples and the tartrazine content in the food samples was permitted according to the guidelines from the European Food Safety Authority (EFSA)
A cloud point extraction (CPE) process using non-ionic surfactant (DC193C) to extract selected paraben compounds from water samples was investigated using reversed phase high performance liquid chromatography (RP-HPLC). The CPE process with the presence of β-cyclodextrin (βCD) functionalized ionic liquid as a modifier (CPE-DC193C-βCD-IL) is a new extraction technique that has been applied on the optimization of parameters, i.e., pH, βCD-IL concentration and phase volume ratio. This CPE-DC193C-βCD-IL method is facilitated at 30 °C, showing great losses of water content in the surfactant-rich phase, resulting in a high pre-concentration factor and high distribution coefficient. The developed method CPE-DC193C-βCD-IL did show enhanced properties compared to the CPE method without the modifier (CPE-DC193C). The developed method of CPE-DC193C-βCD-IL gives an excellent performance on the detection of parabens from water samples with the limit of detection falling in the range of 0.013-0.038 µg mL-1. Finally, the inclusion complex formation, hydrogen bonding, and π-π interaction between the βCD-IL, benzyl paraben (ArP), and DC 193C were proven using 1H NMR and 2D NOESY spectroscopy.