Determination of the Most Toxic Polychlorodibenzofurans in Fresh Milk from Southwest Iran

Abstract

Background: Today's presence of polychlorinated dibenzofurans (PCDFs) in foodstuff, such as milk and milk products, is considered to be the major concern for human health. This study was aimed to determine the concentrations of the most toxic congeners of furans in pasteurized milk samples produced in southwest Iran. Material and method: 15 composite samples of pasteurized milk were collected from 3 major dairy factories in Khuzestan Province (southwest of Iran) in summer, autumn and winter from July 2011 to March 2012. After precipitation of the proteins, fat phase was reduced and extracted with hexane and ether. After dehydration, furans existed in fat percolated with hexane through a column chromatography that contained respectively silica gel/silver nitrate, silica gel, silica gel/sulphuric acid and with percolating output through another column that contained activated charcoal and silica gel and washed the lower column with a mixture of dichloromethane-hexane and toluene, concentrated and dissolved in mobile phase and analyzed using HPLC: 150 mm × 4.6 mm ID, 5 µm cosmosil 5 NPE column equipped with a UV detector at 254 and 235 nm, mobile phase: methanol/water (80:20, v/v) at flow rate of 1 ml/min. Results: All samples were found to be contaminated with furans. The average concentration of 2,3,7,8 TCDF and 2,3,4,7,8 PCDF were 1.91 pg/g and 1.77 pg/g in lipid content ranging from 2% to 3% respectively. The mean total content of furans in milk fat was 0.36 TEQ (Toxic Equivalency) pg/g which was below the recommended EU (European Union) threshold value 3 pg (WHO-PCDFs-TEQ/g fat). Also, result showed that there were statistically significant differences between each factory during 3 seasons.

Simultaneous Determination of 2,3,7,8-TCDD and 2,3,7,8-TCDF in Water Samples by LLE-LTP and HPLC-DAD

“…Several reports 17,18,[23][24][25][26][27] describe the use of acetonitrile and water or methanol and water in different proportions as mobile phase to analyze PCDD/Fs by HPLC. However, the best mobile phase in this study was obtained using only acetonitrile, as can be seen in Figure S3c (SI section).…”

“…Therefore, 30 ºC was chosen because the chromatogram presents a more linear baseline and is in agreement with other studies. 23,24 The chromatogram obtained in optimized conditions for the simultaneous determination of 2,3,7,8-TCDD and 2,3,7,8-TCDF is shown in Figure 1.…”

“…25 The liquid-liquid extraction combined with HPLC-DAD was only used to analyze 2,3,7,8-TCDF, reaching the LOQ of 0.3 µg L -1 , being a lower value to that found in this study. 24 It is worth mentioning that this has been the first work that analyzes these two compounds simultaneously using this methodology.…”

“…5 Previous works quantified PCDD/Fs (0.96 to 3.17 TEQ pg g -1 (2,3,7,8-TCDD) and 1.91 pg g -1 (2,3,7,8-TCDF)) in fresh milk from southwest Iran using liquid-liquid extraction and HPLC-UV. 23,24 The presence of PCDD/Fs in real samples depends on several factors such as matrix type, analyte concentration, sample collection period and extraction and detection methodologies used; therefore, most of the literature studies did not quantify PCDD/Fs in real samples. 1,17,18,20,25,26…”

“…22 After extractions, these compounds are analyzed by different techniques such as high resolution gas chromatography coupled to high resolution mass spectrometry (HRGC-HRMS), which has been applied as a reference methodology established by the USEPA. 19 However, other alternative methodologies have been used such as gas chromatography coupled to mass spectrometry (GC-MS), 20 gas chromatography coupled to electron capture detection (GC-ECD), 1 gas chromatography coupled to mass spectrometry with triple quadrupole detector (GC-MS/MS), 8 high-performance liquid chromatography coupled to ultraviolet detection (HPLC-UV) 18,[23][24][25][26] and high-performance liquid chromatography coupled to fluorescence detection (HPLC-FD). 17,27 This paper aimed to optimize and validate the liquidliquid extraction with low-temperature partition and analyses by high-performance liquid chromatography coupled a diode array detector method (LLE/LTP-HPLC/DAD) for the determination of 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) and 2,3,7,8-tetrachlorodibenzofuran (2,3,7,8-TCDF) in water samples.…”