scholarly journals A New Ultrasonic Assisted Cloud Point Extraction and Preconcentration Procedure for the Spectrophotometric Oxalate Determination in Beverages

2017 ◽  
Vol 1 (45) ◽  
pp. 81-94 ◽  
Author(s):  
Ramazan Gürkan ◽  
Nail Altunay
2012 ◽  
Vol 95 (3) ◽  
pp. 845-849 ◽  
Author(s):  
Mohammad Mirzaei ◽  
Atieh Karimi Naeini ◽  
Mansoureh Behzadi

Abstract A simple and sensitive method has been developed for preconcentration and determination of genistein in soybeans. This method is based on cloud point extraction (CPE) of genistein from soybeans using ethylene glycol monoalkyl ether (Genapol X-080) as a nonionic surfactant. The concentration of extracted genistein was determined by HPLC with a UV detector. Optimum experimental conditions were established. With 5% Genapol X-080 (v/v), a liquid/solid ratio of 25:1 mL/g, and ultrasonic-assisted extraction at 40°C for 45 min, the extraction percentage of genistein reached its highest value. The preconcentration factor for genistein was about 16.5. The RSD for seven replicate measurements and the LOD were ±4.45% and 15.0 ng/mL, respectively. CPE is simple, inexpensive, and suitable for extraction of genistein from soybean. It uses environmentally friendly surfactants and offers a convenient alternative to more conventional extraction systems.


RSC Advances ◽  
2015 ◽  
Vol 5 (80) ◽  
pp. 65321-65327 ◽  
Author(s):  
Chunlei Fan ◽  
Shengxu Luo ◽  
Rong Liu

BTF is exists with spirolactone species with adding Cu2+, which leads to the absorbance intensity is decreased gradually and the decrease of the absorbance value is linear for Cu2+.


2011 ◽  
Vol 94 (4) ◽  
pp. 1304-1309 ◽  
Author(s):  
Regina Terumi Yamaki ◽  
Luana Sena Nunes ◽  
Hygor Rodrigues De Oliveira ◽  
André S Araújo ◽  
Marcos Almeida Bezerra ◽  
...  

Abstract The synthesis and characterization of the reagent 2-(5-bromothiazolylazo)-4-chlorophenol and its application in the development of a preconcentration procedure for cobalt determination using flame atomic absorption spectrometry after cloud point extraction is presented. This procedure is based on cobalt complexing and entrapment of the metal chelates into micelles of a surfactant-rich phase of Triton X-114. The preconcentration procedure was optimized by using a response surface methodology through the application of the Box-Behnken matrix. Under optimum conditions, the procedure determined the presence of cobalt with an LOD of 2.8 μg/L and LOQ of 9.3 μg/L. The enrichment factor obtained was 25. The precision was evaluated as the RSD, which was 5.5% for 10 μg/L cobalt and 6.9% for 30 μg/L. The accuracy of the procedure was assessed by comparing the results with those found using inductively coupled plasma-optical emission spectrometry. After validation, the procedure was applied to the determination of cobalt in pharmaceutical preparation samples containing cobalamin (vitamin B12).


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