Extraction induced by emulsion breaking for As, Se and Hg determination in crude palm oil by vapor generation-AFS

Ionic liquid assisted extraction induced by emulsion breaking for extraction of trace metals in diesel, gasoline and kerosene prior to ICP-OES analysis

This study describes a novel and greener ionic liquid assisted extraction induced by emulsion breaking (ILA-EIEB) method for extraction of As, Ba, Cd, Cr, Ni Pb, Sb, Sn, Tb, Te and V in fuel oils. The most influential extraction parameters were ionic liquid concentration [(1-Ethyl-3-methylimidazolium bis (trifluoromethylsulfonyl)], HNO3 concentration, Triton X-100 concentration, and sample mass and were optimised by using full factorial and Box-Behnken designs. The optimum conditions obtained were 0.035 % 1-Ethyl-3-methylimidazolium bis (trifluoromethylsulfonyl) concentration, 18 % v/v HNO3 concentration, 15 % w/v Triton X-100 concentration, and 0.1 g sample mass. The emulsions were fully broken by using a controlled heating water bath at temperature of 80 ± 2 °C for 30 ± 4 min, followed by centrifugation at 3500 rpm for 15 min. Under the optimum conditions, the proposed ILA-EIEB method was accurate (80.1-101 %) and precise (1.9-4.7 %) for all the investigated metals. The method detection limits were 0.107, 0.013, 3.494 and 0.560 μg/g for Ba, Na, Ni and V, respectively. The optimised ILA-EIEB method was then applied in real fuel samples and metal concentration levels ranged from 0.072 to 8.610 μg/g, which were consistent with other literature reported work. Therefore, this study suggests that the examined metal ions present in fuel oils commercialised in Johannesburg, South Africa are in tolerable concentration levels and are not a threat.

Microwave-assisted hydrogen peroxide digestion followed by ICP-OES for determination of metals in selected fuel oils

This work describes a greener and cost-effective microwave-assisted hydrogen peroxide digestion (MA-HPD) with the addition of 1 mL of HNO3 (70% v/v) to enhance extraction of selected metals (Al, Ba, Cd, Co, Cr, Cu, Mg, Na, Ni, Pb, Sb, Ti and V) in crude-oil, diesel, gasoline and kerosene samples prior to inductively coupled plasma-optical emission spectroscopic (ICP-OES) analysis. The most influential parameters of the MA-HPD method were investigated by using multivariate optimization tools (two-level full factorial and central composite designs) and fuel oil certified reference material (NIST1634c). The optimum conditions were observed to be 245 ℃ microwave temperature, 25 min digestion time, 0.1 g sample mass and 5 M H2O2 were the optimum digestion conditions with accepted accuracy (104.8-117.7%) and precision (≤ 4.1%). In overall, the metals that reported high concentrations in the crude oil, diesel, gasoline, and kerosene samples were Na (51.94-58.86 mg/kg) and Mg (36.08-47.4 mg/kg), while Cu was the lowest (0.55-2.89 mg/kg). When comparing the obtained concentration levels with other literature reports, a conclusion can be drawn that South Africa is importing oils of reasonable quality.

A systematic review and meta-analysis of validated analytical techniques for the determination of total selenium in foods and beverages

The intricate balance between the beneficial and harmful effects of selenium (Se) intake means that its quantification in food needs to be done correctly. Therefore, in this review, we systematized 105 articles to identify the most studied methodologies, analytical techniques, and food matrices. Among the analytical techniques employed, inductively coupled plasma mass spectrometry (ICP-MS) (n = 29) emerged as the most commonly used method. The most prevalent hydrolysis methodology to digest Se in food matrices involved the use of nitric acid combined with ultrasound, which improved both the yield and digestion time. Optimal recovery values were achieved when total Se quantification accounted for the sum of Se(IV) and Se(VI) (94.4-99.4%) and for SeCys (88-96.5%). These findings are relevant for advancing methodological approaches, and their results emphasize the importance of developing alternative, faster, and lower-cost protocols for Se quantification in foods and beverages.

Essential Components from Plant Source Oils: A Review on Extraction, Detection, Identification, and Quantification

Oils derived from plant sources, mainly fixed oils from seeds and essential oil from other parts of the plant, are gaining interest as they are the rich source of beneficial compounds that possess potential applications in different industries due to their preventive and therapeutic actions. The essential oils are used in food, medicine, cosmetics, and agriculture industries as they possess antimicrobial, anticarcinogenic, anti-inflammatory and immunomodulatory properties. Plant based oils contain polyphenols, phytochemicals, and bioactive compounds which show high antioxidant activity. The extractions of these oils are a crucial step in terms of the yield and quality attributes of plant oils. This review paper outlines the different modern extraction techniques used for the extraction of different seed oils, including microwave-assisted extraction (MAE), pressurized liquid extraction (PLE), cold-pressed extraction (CPE), ultrasound-assisted extraction (UAE), supercritical-fluid extraction (SFE), enzyme-assisted extraction (EAE), and pulsed electric field-assisted extraction (PEF). For the identification and quantification of essential and bioactive compounds present in seed oils, different modern techniques-such as high-performance liquid chromatography (HPLC), gas chromatography-mass spectrometry (GC-MS), Fourier transform infrared spectroscopy (FTIR), gas chromatography-infrared spectroscopy (GC-IR), atomic fluorescence spectroscopy (AFS), and electron microscopy (EM)-are highlighted in this review along with the beneficial effects of these essential components in different in vivo and in vitro studies and in different applications. The primary goal of this research article is to pique the attention of researchers towards the different sources, potential uses and applications of oils in different industries.

Extraction Induced by Emulsion and Microemulsion Breaking for Metal Determination by Spectrometric Methods - A Review

This review focuses on extraction induced by the destabilization of emulsified systems combined with spectrometric techniques for metal analysis in oily samples. This approach is based on the formation and breaking of an emulsion (extraction induced by emulsion breaking - EIEB) or microemulsion (extraction induced by microemulsion breaking - EIMB) to transfer the analytes from the oil sample to the aqueous phase, which is separated in the process. Its simplicity, speed, and low cost have contributed to its growing popularity among researchers. However, the potential of EIEB and EIMB is far from being fully exploited. Therefore, this paper aims to provide relevant information to expand the applicability of these methods. The principle of the methods is discussed, and a brief description of emulsified systems is presented. The parameters affecting the extraction efficiency and calibration strategy are also critically discussed. Furthermore, the analytical applications of the methods are reviewed. Trends and opportunities in this field are also considered.