Direct automatic determination of polyphenols in olive oils in the aqueous phase of a flow-injection liquid-liquid extraction system without phase separation

1990 ◽  
Vol 235 ◽  
pp. 441-444 ◽  
Author(s):  
José A.G. Mesa ◽  
Pilar Linares ◽  
M.D. Luque de Castro ◽  
M. Valcárcel
1994 ◽  
Vol 77 (6) ◽  
pp. 1627-1630 ◽  
Author(s):  
Ana M Martín ◽  
Mercedes Sánchez ◽  
Pedro Espinosa ◽  
Gracia Bagur

Abstract A method was developed for the determination of tin based on the extraction of its 5,5-methylenedisalicylohydroxamic acid complex with 1.09M isobutyl methyl ketone in tributyl phosphate. After the samples were treated with nitric and hydrochloric acid, the aqueous phase was made to 0.05M in perchloric acid. When the ratio of aqueous phase to organic phase was 4:1 (v/v), the detection limit and the relative standard deviation (n = 7,50 μg tin) were 0.20 μg/mL and 0.9%, respectively. The proposed method was applied to the analysis of tin in canned fruits and vegetables. The results were in good agreement with those obtained by the phenylfluorone method.


2017 ◽  
Vol 7 (4) ◽  
pp. 44 ◽  
Author(s):  
Takeshi Kato ◽  
Shotaro Saito ◽  
Shigekatsu Oshite ◽  
Shukuro Igarashi

A powerful technique for the concentration of rhodium (Rh) in plating wastewater was developed. The technique entails complexing Rh with 1-(2-pyridylazo)-2-naphthol (PAN) followed by homogeneous liquid–liquid extraction (HoLLE) with Zonyl FSA. The optimum HoLLE conditions were determined as follows: [ethanol]T = 30.0 vol.%, pH = 4.00, and Rh:PAN = 1:5. Under these optimum conditions, 88.1% of Rh was extracted into the sedimented liquid phase. After phase separation, the volume ratio [aqueous phase (Va) /sedimented liquid phase (Vs)] of Va and Vs was 1000 (50 mL → 0.050 mL). We then applied the new method to wastewater generated by the plating industry. The phase separation was satisfactorily achieved when the volume was scaled up to 1000 mL of the actual wastewater; 84.7% of Rh was extracted into the sedimented liquid phase. After phase separation, Va/Vs was 588 (1000 mL - 1.70 mL).


Molecules ◽  
2019 ◽  
Vol 24 (15) ◽  
pp. 2761 ◽  
Author(s):  
Wenbin Chen ◽  
Siyuan Wu ◽  
Jianing Zhang ◽  
Fengjie Yu ◽  
Jianbo Hou ◽  
...  

In the present work, we developed a simple and rapid sample preparation method for the determination of neonicotinoid pesticides in honey based on the matrix-induced sugaring-out. Since there is a high concentration of sugars in the honey matrix, the honey samples were mixed directly with acetonitrile (ACN)-water mixture to trigger the phase separation. Analytes were extracted into the upper ACN phase without additional phase separation agents and injected into the HPLC system for the analysis. Parameters of this matrix-induced sugaring-out method were systematically investigated. The optimal protocol involves 2 g honey mixed with 4 mL ACN-water mixture (v/v, 60:40). In addition, this simple sample preparation method was compared with two other ACN-water-based homogenous liquid-liquid extraction methods, including salting-out assisted liquid-liquid extraction and subzero-temperature assisted liquid-liquid extraction. The present method was fully validated, the obtained limits of detection (LODs) and limits of quantification (LOQs) were from 21 to 27 and 70 to 90 μg/kg, respectively. Average recoveries at three spiked levels were in the range of 91.49% to 97.73%. Precision expressed as relative standard deviations (RSDs) in the inter-day and intra-day analysis were all lower than 5%. Finally, the developed method was applied for the analysis of eight honey samples, results showed that none of the target neonicotinoid residues were detected.


2001 ◽  
Vol 69 (3) ◽  
pp. 199-204 ◽  
Author(s):  
A.R Maurı́-Aucejo ◽  
M.C Pascual-Martı́ ◽  
M Llobat ◽  
A Herraiz ◽  
A Cerdán

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