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Hua Zhang - One of the best experts on this subject based on the ideXlab platform.

  • A simple and sensitive assay for ascorbate using Potassium Ferricyanide as spectroscopic probe reagent.
    Analytical biochemistry, 2009
    Co-Authors: Hua Zhang, Kui Wang
    Abstract:

    Abstract We have developed a rapid, inexpensive, and reliable assay to determine ascorbate using Potassium Ferricyanide as spectroscopic probe reagent. In this assay, Fe(III) was deoxidized to Fe(II) by ascorbate at pH 4.0 and then Fe(II) reacted with Potassium Ferricyanide to form a blue product, soluble Prussian blue (KFeIII[FeII(CN)6]). The absorbance of this product was monitored over time using a spectrophotometer at an absorption maximum of 735 nm and the amount of ascorbate can be calculated based on absorbance. A good linear relationship of the concentration of ascorbate versus absorbance was observed, and the linear regression equation was A = −0.01911 + 0.16208C (μg/ml). Moreover, the apparent molar absorption coefficient of indirect determination of ascorbate was 2.85 × 104 L/mol·cm. To demonstrate the usefulness of this assay, it was used to determine ascorbate in different samples, and we particularly investigated the uptake of ascorbate and ascorbate phosphate in osteoblasts. We found similar plateau levels of intracellular ascorbate at 24 h for ascorbate and ascorbate phosphate. The assay was robust for a variety of samples, including orange juice, fruits, and swine plasma. The assay was quick and very economical and provides results with uncertainties on the order of only 5%.

  • Determination of isoniazid among pharmaceutical samples and the patients’ saliva samples by using Potassium Ferricyanide as spectroscopic probe reagent
    Analytica Chimica Acta, 2008
    Co-Authors: Hua Zhang
    Abstract:

    Abstract A novel method to determine isoniazid with high sensitivity and good selectivity has been established by using Potassium Ferricyanide as spectroscopic probe reagent. In the presence of Potassium Ferricyanide, it has been demonstrated that iron(III) is reduced to iron(II) by isoniazid at pH 4.0. In addition, the in situ formed iron(II) reacts with Potassium Ferricyanide to give soluble prussian blue. The absorbance of soluble prussian blue is measured at the absorption maximum of 735 nm, and the amount of isoniazid can be calculated based on this absorbance. A good linear relationship of the concentration of isoniazid versus absorbance is observed with a linear range of 0.040–8.00 μg mL −1 . The linear regression equation is A  = −0.00286 + 0.28588 C (μg mL −1 ) with a correlation coefficient of 0.9992. The detection limit (3 σ / k ) is 0.037 μg mL −1 , and its relative standard deviation (R.S.D.) is 0.35% ( n  = 11). Moreover, the apparent molar absorption coefficient of indirect determination of isoniazid is 3.92 × 10 4  L mol −1  cm −1 . The parameters with regard to determination are optimized, and the reaction mechanism is discussed. This method has been successfully applied to the determination of isoniazid in pharmaceutical samples and saliva samples of patients.

Yan Zhang - One of the best experts on this subject based on the ideXlab platform.

  • spectrophotometric determination of methimazole in pharmaceutical serum and urine samples by reaction with Potassium Ferricyanide fe iii
    Journal of Analytical Chemistry, 2010
    Co-Authors: Chunhong Dong, Yan Zhang, Li Guo
    Abstract:

    This paper describes a novel method to determine methimazole by spectrophotometry using a Potassium Ferricyanide-Fe(III) reaction. The study indicates that at pH 4.0 Fe(III) is reduced to Fe(II) by methimazole and in situ formed Fe(II) reacts with Potassium Ferricyanide to give soluble Prussian Blue which is characterized by means of XRD analysis. The absorbance of Prussian Blue is measured at the absorption maximum of 735 nm, and the amount of methimazole can be determined based on this absorbance. Beer’s law is obeyed in the range of methimazole concentrations of 0.02–6.00 μg/mL. The equation of the linear regression is A = −0.0058 + 0.49988c (μg/mL), with a correlation coefficient of 0.9998 and RSD of 0.80%. The detection limit (3σ/k) is 0.015 μg/mL, and the apparent molar absorption coefficient of indirect determination of methimazole is 5.7 ± 104 L/mol cm. This method has been successfully applied to the determination of methimazole in pharmaceutical, serum and urine samples, and average recoveries are in the range of 98.6–102.4%. Analytical results obtained with this novel method are satisfactory.

  • Spectrophotometric determination of perphenazine with the detection system of Potassium Ferricyanide-Fe(III) in pharmaceutical and serum samples.
    Spectrochimica acta. Part A Molecular and biomolecular spectroscopy, 2009
    Co-Authors: Li Guo, Yan Zhang
    Abstract:

    Abstract In this paper, a novel spectrophotometric method has been established to determine perphenazine using the detection system of Potassium Ferricyanide–Fe(III). In the presence of Potassium Ferricyanide, it has been demonstrated that Fe(III) is reduced to Fe(II) by perphenazine at pH 4.0. In addition, soluble prussian blue (KFeIII[FeII(CN)6]) is produced by the reaction between the in situ formed Fe(II) and Potassium Ferricyanide. The absorbance of soluble prussian blue is measured at the absorption maximum of 735 nm, and the amount of perphenazine can be calculated based on this absorbance. The absorbance is linear to perphenazine concentration in the ranges of 0.05–25.00 μg/mL with correlation coefficients of 0.9997, and the linear regression equation is A = 0.0069 + 0.1285C (μg/mL). The detection limit (3σ/k) is 0.049 μg/mL, and the relative standard deviation (R.S.D.) is 0.86% (n = 11). Moreover, the apparent molar absorption coefficient of indirect determination of perphenazine is 5.2 × 104 L/mol cm. The parameters with regard to determination are optimized, and the reaction mechanism is discussed. This method has been successfully applied to the determination of perphenazine in pharmaceutical and serum samples. Analytical results obtained with this novel assay are satisfactory.

  • A Novel Spectrophotometric Method for the Determination of Levodopa with the Detection System of Potassium Ferricyanide-Fe(III)
    Journal of the Chinese Chemical Society, 2009
    Co-Authors: Li Guo, Yan Zhang
    Abstract:

    In this paper, a novel method has been established to determine levodopa with the detection system of Potassium Ferricyanide-Fe(III). In the presence of Potassium Ferricyanide, it has been demonstrated that Fe(III) is reduced to Fe(II) by levodopa at pH 4.0. In addition, the in situ formed Fe(II) reacts with Potassium Ferricyanide to form soluble prussian blue (KFe III [Fe II (CN) 6 ]). Beer's law is obeyed in the range of levodopa concentrations of 0.01-4.00 μg mL -1 at the maximal absorption wavelength of 735 nm. The linear regression equation is A = 0.0082 + 0.61365 C (μg mL -1 ) with a correlation coefficient of 0.9996. The detection limit (3σ/k) is 9 ng mL -1 and R.S.D. is 0.73% (n = 11). Moreover, the apparent molar absorption coefficient of indirect determination of levodopa is 1.2 x 10 5 Lmol -1 cm -1 . The parameters with regard to determination are optimized, and the reaction mechanism is discussed. This method has been successfully applied to determine levodopa in pharmaceutical, serum and urine samples. Analytical results obtained with this novel assay are satisfactory.

  • Spectrophotometric Determination of Dopamine Hydrochloride in Pharmaceutical, Banana, Urine and Serum Samples by Potassium Ferricyanide-Fe(III)
    Analytical sciences : the international journal of the Japan Society for Analytical Chemistry, 2009
    Co-Authors: Li Guo, Yan Zhang
    Abstract:

    In the present work, we developed a simple, sensitive and inexpensive method to determine dopamine hydrochloride using Potassium Ferricyanide-Fe(III) by spectrophotometry. The results show that Fe(III) is deoxidized to Fe(II) by dopamine hydrochloride at pH 4.0, and then Fe(II) reacts with Potassium Ferricyanide to form a soluble prussian blue (KFe(III)[Fe(II)(CN)6]). The absorbance of this product was monitored over time using a spectrophotometer at an absorption maximum of 735 nm, and the amount of dopamine hydrochloride could be calculated based on the absorbance. A good linear relationship of the concentration of dopamine hydrochloride versus absorbance was observed, and a linear regression equation of A = 0.022 + 0.16921C (microg mL(-1)) was obtained. Moreover, the apparent molar absorption coefficient for the indirect determination of dopamine hydrochloride was 3.2 x 10(4) L mol(-1) cm(-1). This described method has been used to determine dopamine hydrochloride in pharmaceutical, banana, urine and serum samples with satisfactory results.

Yihua Zhang - One of the best experts on this subject based on the ideXlab platform.

Weiping Yin - One of the best experts on this subject based on the ideXlab platform.

  • selective para cyanation of alkoxy and benzyloxy substituted benzenes with Potassium Ferricyanide promoted by copper ii nitrate and iodine
    Advanced Synthesis & Catalysis, 2012
    Co-Authors: Yunlai Ren, Mengjie Yan, Shuang Zhao, Jianji Wang, Xinzhe Tian, Weiping Yin
    Abstract:

    A simple method was developed for selective para-cyanation of alkoxy- and benzyloxy-substituted benzenes with 0.5 equivalents of Potassium Ferricyanide, 0.8 equivalants of copper(II) nitrate and 0.5 equivalents of iodine in acetonitrile. Among various phenyl carbon-hydrogen bonds, those at the para-position with regard to the alkoxy or benzyloxy groups were selectively cyanated in 20% to 87% yields (23 examples). The present method uses commercially available reagents, and can be performed on a ten gram-scale. Interestingly, methoxybenzene was cyanated in 32% yield in the absence of Potassium Ferricyanide, which suggests that the nitrile group of a part of the product is possibly from the solvent acetonitrile.

  • Selective para‐Cyanation of Alkoxy‐ and Benzyloxy‐Substituted Benzenes with Potassium Ferricyanide Promoted by Copper(II) Nitrate and Iodine
    Advanced Synthesis & Catalysis, 2012
    Co-Authors: Yunlai Ren, Mengjie Yan, Shuang Zhao, Jianji Wang, Xinzhe Tian, Weiping Yin
    Abstract:

    A simple method was developed for selective para-cyanation of alkoxy- and benzyloxy-substituted benzenes with 0.5 equivalents of Potassium Ferricyanide, 0.8 equivalants of copper(II) nitrate and 0.5 equivalents of iodine in acetonitrile. Among various phenyl carbon-hydrogen bonds, those at the para-position with regard to the alkoxy or benzyloxy groups were selectively cyanated in 20% to 87% yields (23 examples). The present method uses commercially available reagents, and can be performed on a ten gram-scale. Interestingly, methoxybenzene was cyanated in 32% yield in the absence of Potassium Ferricyanide, which suggests that the nitrile group of a part of the product is possibly from the solvent acetonitrile.

Li Guo - One of the best experts on this subject based on the ideXlab platform.

  • spectrophotometric determination of methimazole in pharmaceutical serum and urine samples by reaction with Potassium Ferricyanide fe iii
    Journal of Analytical Chemistry, 2010
    Co-Authors: Chunhong Dong, Yan Zhang, Li Guo
    Abstract:

    This paper describes a novel method to determine methimazole by spectrophotometry using a Potassium Ferricyanide-Fe(III) reaction. The study indicates that at pH 4.0 Fe(III) is reduced to Fe(II) by methimazole and in situ formed Fe(II) reacts with Potassium Ferricyanide to give soluble Prussian Blue which is characterized by means of XRD analysis. The absorbance of Prussian Blue is measured at the absorption maximum of 735 nm, and the amount of methimazole can be determined based on this absorbance. Beer’s law is obeyed in the range of methimazole concentrations of 0.02–6.00 μg/mL. The equation of the linear regression is A = −0.0058 + 0.49988c (μg/mL), with a correlation coefficient of 0.9998 and RSD of 0.80%. The detection limit (3σ/k) is 0.015 μg/mL, and the apparent molar absorption coefficient of indirect determination of methimazole is 5.7 ± 104 L/mol cm. This method has been successfully applied to the determination of methimazole in pharmaceutical, serum and urine samples, and average recoveries are in the range of 98.6–102.4%. Analytical results obtained with this novel method are satisfactory.

  • Spectrophotometric determination of perphenazine with the detection system of Potassium Ferricyanide-Fe(III) in pharmaceutical and serum samples.
    Spectrochimica acta. Part A Molecular and biomolecular spectroscopy, 2009
    Co-Authors: Li Guo, Yan Zhang
    Abstract:

    Abstract In this paper, a novel spectrophotometric method has been established to determine perphenazine using the detection system of Potassium Ferricyanide–Fe(III). In the presence of Potassium Ferricyanide, it has been demonstrated that Fe(III) is reduced to Fe(II) by perphenazine at pH 4.0. In addition, soluble prussian blue (KFeIII[FeII(CN)6]) is produced by the reaction between the in situ formed Fe(II) and Potassium Ferricyanide. The absorbance of soluble prussian blue is measured at the absorption maximum of 735 nm, and the amount of perphenazine can be calculated based on this absorbance. The absorbance is linear to perphenazine concentration in the ranges of 0.05–25.00 μg/mL with correlation coefficients of 0.9997, and the linear regression equation is A = 0.0069 + 0.1285C (μg/mL). The detection limit (3σ/k) is 0.049 μg/mL, and the relative standard deviation (R.S.D.) is 0.86% (n = 11). Moreover, the apparent molar absorption coefficient of indirect determination of perphenazine is 5.2 × 104 L/mol cm. The parameters with regard to determination are optimized, and the reaction mechanism is discussed. This method has been successfully applied to the determination of perphenazine in pharmaceutical and serum samples. Analytical results obtained with this novel assay are satisfactory.

  • A Novel Spectrophotometric Method for the Determination of Levodopa with the Detection System of Potassium Ferricyanide-Fe(III)
    Journal of the Chinese Chemical Society, 2009
    Co-Authors: Li Guo, Yan Zhang
    Abstract:

    In this paper, a novel method has been established to determine levodopa with the detection system of Potassium Ferricyanide-Fe(III). In the presence of Potassium Ferricyanide, it has been demonstrated that Fe(III) is reduced to Fe(II) by levodopa at pH 4.0. In addition, the in situ formed Fe(II) reacts with Potassium Ferricyanide to form soluble prussian blue (KFe III [Fe II (CN) 6 ]). Beer's law is obeyed in the range of levodopa concentrations of 0.01-4.00 μg mL -1 at the maximal absorption wavelength of 735 nm. The linear regression equation is A = 0.0082 + 0.61365 C (μg mL -1 ) with a correlation coefficient of 0.9996. The detection limit (3σ/k) is 9 ng mL -1 and R.S.D. is 0.73% (n = 11). Moreover, the apparent molar absorption coefficient of indirect determination of levodopa is 1.2 x 10 5 Lmol -1 cm -1 . The parameters with regard to determination are optimized, and the reaction mechanism is discussed. This method has been successfully applied to determine levodopa in pharmaceutical, serum and urine samples. Analytical results obtained with this novel assay are satisfactory.

  • Spectrophotometric Determination of Dopamine Hydrochloride in Pharmaceutical, Banana, Urine and Serum Samples by Potassium Ferricyanide-Fe(III)
    Analytical sciences : the international journal of the Japan Society for Analytical Chemistry, 2009
    Co-Authors: Li Guo, Yan Zhang
    Abstract:

    In the present work, we developed a simple, sensitive and inexpensive method to determine dopamine hydrochloride using Potassium Ferricyanide-Fe(III) by spectrophotometry. The results show that Fe(III) is deoxidized to Fe(II) by dopamine hydrochloride at pH 4.0, and then Fe(II) reacts with Potassium Ferricyanide to form a soluble prussian blue (KFe(III)[Fe(II)(CN)6]). The absorbance of this product was monitored over time using a spectrophotometer at an absorption maximum of 735 nm, and the amount of dopamine hydrochloride could be calculated based on the absorbance. A good linear relationship of the concentration of dopamine hydrochloride versus absorbance was observed, and a linear regression equation of A = 0.022 + 0.16921C (microg mL(-1)) was obtained. Moreover, the apparent molar absorption coefficient for the indirect determination of dopamine hydrochloride was 3.2 x 10(4) L mol(-1) cm(-1). This described method has been used to determine dopamine hydrochloride in pharmaceutical, banana, urine and serum samples with satisfactory results.