Extraction induced by emulsion breaking to assay Cr, Cu and Mn in asphalt samples by high-resolution continuum source atomic absorption spectrometry and its comparison with other sample preparation methods

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

“…It is worthy to indicate that oils with high viscosity do not perform well for the extraction of metals using EIEB [ 38 ]. This is because, high viscosity oils get stuck on the container walls, thereby limit the formation of emulsion with the aqueous phase [ 39 ]. To overcome this challenge, some researchers have introduced carcinogenic organic solvents (toluene, hexane, and xylene) as diluents, however, too diluted oils would result in unstable emulsions, thereby reduce extraction recoveries [ 17 , 31 ].…”

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

“…The hydrocarbon class types that are found in crudes are paraffinic, naphthenic, aromatic and asphaltic 2 . Crudes with high metal content are undesirable since the metals can act as catalyst poison, reducing catalyst activity which result in slowed refinery process 3 . Metals such as nickel, iron and vanadium have a long history of being problematic to refiners 4 .…”

“…Crude oil is then refined to form crude oil fractions like gasoline, diesel, kerosene, just to name the few. When gasoline and diesel are combusted, the presence of Cu, Fe, Co and Mn can catalyse the oxidation reaction, thereby causing low combustion efficiency, resulting in unburnt deposits and also cause metal laydown in the cylinder 3 . Therefore, the challenges associated with metals in crude oil and crude oil fractions have ignited an interest for many researchers to conduct investigations on the development of analytical methods for quantitative determination of metals in various fuel oils.…”

Highly Sensitive Hydrogel Gratings for Real-Time Detection of Trace Hexavalent Chromium Ions in Water

“…Hexavalent chromium ion [Cr­(VI)], which is a common groundwater contaminant, is a severe threat to eco-system health and sustainability even at trace amounts. − For example, Cr­(VI) can be easily absorbed by humans through the respiratory tract and skin, leading to genetic defects and strong carcinogenesis. − Even in 2016, a US Environmental Working Group investigation found that many people were drinking tap water contaminated with Cr­(VI) due to the effluent discharge from a phosphate fertilizer plant. , Due to the harmful effect of Cr­(VI), the World Health Organization provides high-level restriction on Cr­(VI) content in drinking water (<9.7 × 10 –7 M); therefore, the detection of such trace amounts of Cr­(VI) is very important. Although such a detection can be achieved by using conventional methods such as atomic absorption spectroscopy , and inductively coupled plasma–mass spectrometry, , they are still limited by the requirements of expensive bulky instruments, professional operators, and time-consuming operation protocols. Meanwhile, emerging techniques, such as microcantilever sensors, surface plasmon resonance-based fiber optic sensors, and fiber Bragg gratings, − are developed to advance the sensitive detection of Cr­(VI).…”

“…9,10 Due to the harmful effect of Cr(VI), the World Health Organization provides high-level restriction on Cr(VI) content in drinking water (<9.7 × 10 −7 M); therefore, the detection of such trace amounts of Cr(VI) is very important. Although such a detection can be achieved by using conventional methods such as atomic absorption spectroscopy 11,12 and inductively coupled plasma−mass spectrometry, 13,14 they are still limited by the requirements of expensive bulky instruments, professional operators, and time-consuming operation protocols. Meanwhile, emerging techniques, such as microcantilever sensors, 15 surface plasmon resonance-based fiber optic sensors, 16 and fiber Bragg gratings, 17−19 are developed to advance the sensitive detection of Cr(VI).…”