scholarly journals DETERMINATION OF POLYCYCLIC AROMATIC HYDROCARBONS (PAHS) IN AQUEOUS SAMPLES BY HPLC-FLD WITH SALTING-OUT LIQUID-LIQUID EXTRACTION

2019 ◽  
Vol 16 (31) ◽  
pp. 95-110
Author(s):  
Byron ACOSTA ◽  
Isabel CIPRIANI-AVILA

Polycyclic aromatic hydrocarbons (PAHs) are a group of more than 100 different chemical substances, which contain two, or more fused aromatic rings most of them toxic or carcinogenic. In this study, the Quechers extraction conditions were adapted to perform the extraction of aqueous samples. Quechers has become a standard technique for the analysis of pesticides and other organic substances. Its simplicity and low cost have made it popular in laboratories around the world for processing samples such as fruits and vegetables. The success of this method on solid samples contrasts with the advances in the extraction of aqueous samples where tedious steps of extraction, concentration and solvent changes must be carried out prior to the instrumental analysis. A methodology for the liquid-liquid extraction (water/acetonitrile) of 15 PAHs in aqueous matrices was developed. The mixture was saturated with anhydrous sodium sulfate to cause the partitioning and the extract was analyzed by High-Resolution Liquid Chromatography with Fluorescence Detection (HPLCFLD). The recoveries of analytes achieved (61-114%) were comparable to those expected using traditional extraction techniques, and with moderate uncertainty. The results were consistent with the expectations for of the required analytical and concentration ranges.

2005 ◽  
Vol 88 (4) ◽  
pp. 1247-1254 ◽  
Author(s):  
Sandra Martinez-López ◽  
Asuncion Morales-Noé ◽  
Agustin Pastor-Garcia ◽  
Angel Morales-Rubio ◽  
Miguel de la Guardia

Abstract The determination of 15 polycyclic aromatic hydrocarbons (PAHs) in olive oil samples has been improved in order to obtain a fast methodology with a low limit of detection through the combination of liquid–liquid extraction with acetonitrile and preparative gel permeation chromatography (GPC) prior to the injection of purified extracts into a C18 column. Acetonitrile–water was used as the mobile phase with a gradient from 50 to 95%, w/w, acetonitrile in 30 min. The oven temperature was maintained at 15°C, and fluorometric detection was made at a fixed excitation wavelength of 264 nm and variable, optimal emission wavelength for each analyte ranging from 352 nm for 11-H-benzo(b)fluorene to 500 nm for indeno(1,2,3-cd)pyrene. Recovery for all the compounds studied varied from 75 to 111%, and limit of detection values from 0.05 ng/g for benzo(k)fluoranthene to 0.48 ng/g for indeno(1,2,3-cd)pyrene, corresponding to 0.09 ng/g benzo(a)pyrene. Results were compared with those obtained by liquid–liquid extraction followed by a cleanup on silica and a direct GPC treatment of oil samples diluted in dichloromethane, 2 other methodologies that are appropriate for quantifying PAHs in olive oils. However, the proposed method improves the determination limits, reduces the time of analysis, and provides a highly stable baseline for sample chromatograms.


2017 ◽  
Vol 82 (1) ◽  
pp. 107-116
Author(s):  
Kahina Bedda ◽  
Boudjema Hamada ◽  
Nikolay Kuzichkin ◽  
Kirill Semikin

The purification of a hydrotreated gas oil by liquid-liquid extraction with N-methylpyrrolidone as solvent has been studied. The results showed that this method, under appropriate experimental conditions, has reduced sulphur content of the gas oil from 174 ppm to 28 ppm, nitrogen content has decreased from 58 ppm to 15 ppm, aromatics content has diminished from 27.1 % to 13.8 % and the polycyclic aromatic hydrocarbons were totally extracted. The refined gas oil obtained can be used to produce clean diesel fuel for the environment.


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