Cloud point extraction (CPE) is proposed as a pre-concentration procedure for the determination of Hg in Chinese herbal medicine samples by @entity7470 generation-atomic fluorescence spectrometry (HG-AFS). Hg2+ was reacted with @entity8059 to form hydrophobic chelate under the condition of pH. Using @entity10385 , as surfactant, chelate was quantitatively extracted into small volume of the surfactant-rich phase by heating the solution in a water bath for 15 min and centrifuging. Four variables including pH, @entity8059 concentration, @entity10385 concentration and equilibrium temperature (T) showed the significant effect on extraction efficiency of total Hg evaluated by single-factor experiment, and Box-Behnken design and response surface method- ology were adopted to further investigate the mutual interactions between these variables and to identify their optimal values that would generate maximum extraction efficiency. The results showed that the binomial was used to fit the response to experimental levels of each variable. ALL linear, quadratic terms of four variables, and interactions between pH and Trion X-114, pH and di- thizone affected the response value(extraction efficiency) significantly at 5% level. The optimum extraction conditions were as follows: pH 5.1, @entity10385 concentration of 1.16 g x L(-1), @entity8059 concentration of 4.87 mol x L(-1), and T 58.2 degrees C, the predicted value of fluorescence was 4528.74 under the optimum conditions, and the experimental value had only 2.1% difference with it. Under the conditions, fluorescence was linear to @entity349 concentration in the range of 1-5 microg x L(-1). The limit of detection obtained was 0.01247 microg x L(-1) with the relative standard deviations (R.S.D.) for six replicate determinations of 1.30%. The proposed method was successfully applied to determination of Hg in morindae Radix, Andrographitis and dried tangerine samples with the recoveries of 95.0%-100.0%. Apparently Box-Behnken design combined with response surface analysis method was considered to be well used for optimization of the cloud point extraction.

[Cloud Point extraction for determination of XXXX in Chinese herbal medicine by @entity7470 generation atomic fluorescence spectrometry with optimization using Box-Behnken design].

@entity10385 :: ('MESH:C010615', 'Chemical') :: ['Triton X-114'] @entity349 :: ('MESH:D008628', 'Chemical') :: ['mercury'] @entity8059 :: ('MESH:D004230', 'Chemical') :: ['dithizone'] @entity7470 :: ('CHEBI:29239', 'Chemical') :: ['hydride']
@entity349 :: (MESH:D008628,Chemical) :: ['mercury']
