The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform

Feng Zheng - One of the best experts on this subject based on the ideXlab platform.

  • determination of trace Methanesulfonates in drug matrix using derivatization and headspace single drop microextraction followed by high performance liquid chromatography with ultraviolet detection
    Journal of Chromatography A, 2019
    Co-Authors: Lan Luo, Jie Zhou, Feng Zheng, Jing Liu
    Abstract:

    Abstract The selective and sensitive determination of potential genotoxic methanesulfonate impurities in drug substances is highly challenging. A new method is reported for testing of methyl methanesulfonate (MMS), ethyl methanesulfonate (EMS) and isopropyl methanesulfonate (IPMS) in active pharmaceutical ingredients (APIs). Headspace single drop microextraction (HS-SDME) with room-temperature ionic liquid (RTIL) as extractant was employed to preconcentrate analytes and eliminate the drug matrix simultaneously. In order to increase volatilities for HS extraction and to improve their reactivity of the further derivatization at the same time, sodium iodide (NaI) was added to the sample to derivatize Methanesulfonates to the corresponding iodoalkanes. The iodoalkanes in the extract were derivatized with N, N-diethyldithiocarbamate (DDTC) after HS-SDME, followed by separation and detection with high-performance liquid chromatography with ultraviolet detection (HPLC-UV). Several important parameters, including reaction temperature, reaction time and concentration of NaI, sample volume, microdrop volume, stirring rate, salt addition, extraction time, concentration, reaction time and reaction temperature of DDTC were investigated. Under the optimal conditions, LODs and LOQs of all Methanesulfonates were 15 ng mL−1 and 40 ng mL−1, respectively. Linearity (correlation coefficient values r > 0.999) and precision (the relative standard deviations were 1.0–4.6%) of six repeated injections were obtained. The recoveries at three spiked concentration levels were all in the range of 86.2–107.5% with the relative standard deviations

  • determination of methyl methanesulfonate and ethyl methanesulfonate in methanesulfonic acid by derivatization followed by high performance liquid chromatography with ultraviolet detection
    IEEE Journal of Solid-state Circuits, 2017
    Co-Authors: Jie Zhou, Xiangyuan Zheng, Wenyuan Liu, Feng Zheng
    Abstract:

    Methanesulfonic acid is routinely used in pharmaceuticals but can contain potentially genotoxic impurities such as methyl methanesulfonate and ethyl methanesulfonate. The aim of this study was to develop a simple high-performance liquid chromatography with ultraviolet detection method for determining methyl methanesulfonate and ethyl methanesulfonate in methanesulfonic acid. Samples (250 mg) in water/acetonitrile (200 μL) were first combined with 10.0 mol/L sodium hydroxide solution (270 μL). Then they were mixed with 2.0 mg/mL N,N-diethyldithiocarbamate (500 μL), diluted to 5 mL with N,N-dimethylacetamide and allowed to react at 80°C for 1 h. The derivatives were analyzed using gradient high-performance liquid chromatography with ultraviolet detection (277 nm) and structurally elucidated by liquid chromatography with mass spectrometry. With acetonitrile/5 mmol/L ammonium acetate solution as the eluent and 1 mL/min as the flow rate on a C18 column, the derivatives were eluted at 10.6 and 14.8 min. Good linearity (correlation coefficients > 0.999) and low limits of quantitation (0.6 ppm) were obtained. The recoveries were in the range of 80-115% with relative standard deviation < 5.0%. Finally, the established method was successfully used for the determination of methyl methanesulfonate and ethyl methanesulfonate in methanesulfonic acid.

Mathias S Wickleder - One of the best experts on this subject based on the ideXlab platform.

  • Methanesulfonates of high valent metals syntheses and structural features of moo2 ch3so3 2 uo2 ch3so3 2 reo3 ch3so3 vo ch3so3 2 and v2o3 ch3so3 4 and their thermal decomposition under n2 and o2 atmosphere
    ChemInform, 2012
    Co-Authors: Ulf Betke, Kai Neuschulz, Mathias S Wickleder
    Abstract:

    The title compounds are the first examples of solvent-free oxide Methanesulfonates of Mo, U, Re, and V.

  • Methanesulfonates of high valent metals syntheses and structural features of moo2 ch3so3 2 uo2 ch3so3 2 reo3 ch3so3 vo ch3so3 2 and v2o3 ch3so3 4 and their thermal decomposition under n2 and o2 atmosphere
    Chemistry: A European Journal, 2011
    Co-Authors: Ulf Betke, Kai Neuschulz, Mathias S Wickleder
    Abstract:

    Oxide Methanesulfonates of Mo, U, Re, and V have been prepared by reaction of MoO(3), UO(2)(CH(3)COO)(2)·2H(2)O, Re(2)O(7)(H(2)O)(2), and V(2)O(5) with CH(3)SO(3)H or mixtures thereof with its anhydride. These compounds are the first examples of solvent-free oxide Methanesulfonates of these elements. MoO(2)(CH(3)SO(3))(2) (Pbca, a=1487.05(4), b=752.55(2), c=1549.61(5) pm, V=1.73414(9) nm(3), Z=8) contains [MoO(2)] moieties connected by [CH(3)SO(3)] ions to form layers parallel to (100). UO(2)(CH(3)SO(3))(2) (P2(1)/c, a=1320.4(1), b=1014.41(6), c=1533.7(1) pm, β=112.80(1)°, V=1.8937(3) nm(3), Z=8) consists of linear UO(2)(2+) ions coordinated by five [CH(3)SO(3)] ions, forming a layer structure. VO(CH(3)SO(3))(2) (P2(1)/c, a=1136.5(1), b=869.87(7), c=915.5(1) pm, β=113.66(1)°, V=0.8290(2) nm(3), Z=4) contains [VO] units connected by methanesulfonate anions to form corrugated layers parallel to (100). In ReO(3)(CH(3)SO(3)) (P1, a=574.0(1), b=1279.6(3), c=1641.9(3) pm, α=102.08(2), β=96.11(2), γ=99.04(2)°, V=1.1523(4) nm(3), Z=8) a chain structure exhibiting infinite O-[ReO(2)]-O-[ReO(2)]-O chains is formed. Each [ReO(2)]-O-[ReO(2)] unit is coordinated by two bidentate [CH(3)SO(3)] ions. V(2)O(3)(CH(3)SO(3))(4) (I2/a, a=1645.2(3), b=583.1(1), c=1670.2(3) pm, β=102.58(3), V=1.5637(5) pm(3), Z=4) adopts a chain structure, too, but contains discrete [VO]-O-[VO] moieties, each coordinated by two bidentate [CH(3)SO(3)] ligands. Additional methanesulfonate ions connect the [V(2)O(3)] groups along [001]. Thermal decomposition of the compounds was monitored under N(2) and O(2) atmosphere by thermogravimetric/differential thermal analysis and XRD measurements. Under N(2) the decomposition proceeds with reduction of the metal leading to the oxides MoO(2), U(3)O(7), V(4)O(7), and VO(2); for MoO(2)(CH(3)SO(3))(2), a small amount of MoS(2) is formed. If the thermal decomposition is carried out in a atmosphere of O(2) the oxides MoO(3) and V(2)O(5) are formed.

Jie Zhou - One of the best experts on this subject based on the ideXlab platform.

  • determination of trace Methanesulfonates in drug matrix using derivatization and headspace single drop microextraction followed by high performance liquid chromatography with ultraviolet detection
    Journal of Chromatography A, 2019
    Co-Authors: Lan Luo, Jie Zhou, Feng Zheng, Jing Liu
    Abstract:

    Abstract The selective and sensitive determination of potential genotoxic methanesulfonate impurities in drug substances is highly challenging. A new method is reported for testing of methyl methanesulfonate (MMS), ethyl methanesulfonate (EMS) and isopropyl methanesulfonate (IPMS) in active pharmaceutical ingredients (APIs). Headspace single drop microextraction (HS-SDME) with room-temperature ionic liquid (RTIL) as extractant was employed to preconcentrate analytes and eliminate the drug matrix simultaneously. In order to increase volatilities for HS extraction and to improve their reactivity of the further derivatization at the same time, sodium iodide (NaI) was added to the sample to derivatize Methanesulfonates to the corresponding iodoalkanes. The iodoalkanes in the extract were derivatized with N, N-diethyldithiocarbamate (DDTC) after HS-SDME, followed by separation and detection with high-performance liquid chromatography with ultraviolet detection (HPLC-UV). Several important parameters, including reaction temperature, reaction time and concentration of NaI, sample volume, microdrop volume, stirring rate, salt addition, extraction time, concentration, reaction time and reaction temperature of DDTC were investigated. Under the optimal conditions, LODs and LOQs of all Methanesulfonates were 15 ng mL−1 and 40 ng mL−1, respectively. Linearity (correlation coefficient values r > 0.999) and precision (the relative standard deviations were 1.0–4.6%) of six repeated injections were obtained. The recoveries at three spiked concentration levels were all in the range of 86.2–107.5% with the relative standard deviations

  • determination of methyl methanesulfonate and ethyl methanesulfonate in methanesulfonic acid by derivatization followed by high performance liquid chromatography with ultraviolet detection
    IEEE Journal of Solid-state Circuits, 2017
    Co-Authors: Jie Zhou, Xiangyuan Zheng, Wenyuan Liu, Feng Zheng
    Abstract:

    Methanesulfonic acid is routinely used in pharmaceuticals but can contain potentially genotoxic impurities such as methyl methanesulfonate and ethyl methanesulfonate. The aim of this study was to develop a simple high-performance liquid chromatography with ultraviolet detection method for determining methyl methanesulfonate and ethyl methanesulfonate in methanesulfonic acid. Samples (250 mg) in water/acetonitrile (200 μL) were first combined with 10.0 mol/L sodium hydroxide solution (270 μL). Then they were mixed with 2.0 mg/mL N,N-diethyldithiocarbamate (500 μL), diluted to 5 mL with N,N-dimethylacetamide and allowed to react at 80°C for 1 h. The derivatives were analyzed using gradient high-performance liquid chromatography with ultraviolet detection (277 nm) and structurally elucidated by liquid chromatography with mass spectrometry. With acetonitrile/5 mmol/L ammonium acetate solution as the eluent and 1 mL/min as the flow rate on a C18 column, the derivatives were eluted at 10.6 and 14.8 min. Good linearity (correlation coefficients > 0.999) and low limits of quantitation (0.6 ppm) were obtained. The recoveries were in the range of 80-115% with relative standard deviation < 5.0%. Finally, the established method was successfully used for the determination of methyl methanesulfonate and ethyl methanesulfonate in methanesulfonic acid.

Ulf Betke - One of the best experts on this subject based on the ideXlab platform.

  • Methanesulfonates of high valent metals syntheses and structural features of moo2 ch3so3 2 uo2 ch3so3 2 reo3 ch3so3 vo ch3so3 2 and v2o3 ch3so3 4 and their thermal decomposition under n2 and o2 atmosphere
    ChemInform, 2012
    Co-Authors: Ulf Betke, Kai Neuschulz, Mathias S Wickleder
    Abstract:

    The title compounds are the first examples of solvent-free oxide Methanesulfonates of Mo, U, Re, and V.

  • Methanesulfonates of high valent metals syntheses and structural features of moo2 ch3so3 2 uo2 ch3so3 2 reo3 ch3so3 vo ch3so3 2 and v2o3 ch3so3 4 and their thermal decomposition under n2 and o2 atmosphere
    Chemistry: A European Journal, 2011
    Co-Authors: Ulf Betke, Kai Neuschulz, Mathias S Wickleder
    Abstract:

    Oxide Methanesulfonates of Mo, U, Re, and V have been prepared by reaction of MoO(3), UO(2)(CH(3)COO)(2)·2H(2)O, Re(2)O(7)(H(2)O)(2), and V(2)O(5) with CH(3)SO(3)H or mixtures thereof with its anhydride. These compounds are the first examples of solvent-free oxide Methanesulfonates of these elements. MoO(2)(CH(3)SO(3))(2) (Pbca, a=1487.05(4), b=752.55(2), c=1549.61(5) pm, V=1.73414(9) nm(3), Z=8) contains [MoO(2)] moieties connected by [CH(3)SO(3)] ions to form layers parallel to (100). UO(2)(CH(3)SO(3))(2) (P2(1)/c, a=1320.4(1), b=1014.41(6), c=1533.7(1) pm, β=112.80(1)°, V=1.8937(3) nm(3), Z=8) consists of linear UO(2)(2+) ions coordinated by five [CH(3)SO(3)] ions, forming a layer structure. VO(CH(3)SO(3))(2) (P2(1)/c, a=1136.5(1), b=869.87(7), c=915.5(1) pm, β=113.66(1)°, V=0.8290(2) nm(3), Z=4) contains [VO] units connected by methanesulfonate anions to form corrugated layers parallel to (100). In ReO(3)(CH(3)SO(3)) (P1, a=574.0(1), b=1279.6(3), c=1641.9(3) pm, α=102.08(2), β=96.11(2), γ=99.04(2)°, V=1.1523(4) nm(3), Z=8) a chain structure exhibiting infinite O-[ReO(2)]-O-[ReO(2)]-O chains is formed. Each [ReO(2)]-O-[ReO(2)] unit is coordinated by two bidentate [CH(3)SO(3)] ions. V(2)O(3)(CH(3)SO(3))(4) (I2/a, a=1645.2(3), b=583.1(1), c=1670.2(3) pm, β=102.58(3), V=1.5637(5) pm(3), Z=4) adopts a chain structure, too, but contains discrete [VO]-O-[VO] moieties, each coordinated by two bidentate [CH(3)SO(3)] ligands. Additional methanesulfonate ions connect the [V(2)O(3)] groups along [001]. Thermal decomposition of the compounds was monitored under N(2) and O(2) atmosphere by thermogravimetric/differential thermal analysis and XRD measurements. Under N(2) the decomposition proceeds with reduction of the metal leading to the oxides MoO(2), U(3)O(7), V(4)O(7), and VO(2); for MoO(2)(CH(3)SO(3))(2), a small amount of MoS(2) is formed. If the thermal decomposition is carried out in a atmosphere of O(2) the oxides MoO(3) and V(2)O(5) are formed.

Xiangyuan Zheng - One of the best experts on this subject based on the ideXlab platform.

  • determination of methyl methanesulfonate and ethyl methanesulfonate in methanesulfonic acid by derivatization followed by high performance liquid chromatography with ultraviolet detection
    IEEE Journal of Solid-state Circuits, 2017
    Co-Authors: Jie Zhou, Xiangyuan Zheng, Wenyuan Liu, Feng Zheng
    Abstract:

    Methanesulfonic acid is routinely used in pharmaceuticals but can contain potentially genotoxic impurities such as methyl methanesulfonate and ethyl methanesulfonate. The aim of this study was to develop a simple high-performance liquid chromatography with ultraviolet detection method for determining methyl methanesulfonate and ethyl methanesulfonate in methanesulfonic acid. Samples (250 mg) in water/acetonitrile (200 μL) were first combined with 10.0 mol/L sodium hydroxide solution (270 μL). Then they were mixed with 2.0 mg/mL N,N-diethyldithiocarbamate (500 μL), diluted to 5 mL with N,N-dimethylacetamide and allowed to react at 80°C for 1 h. The derivatives were analyzed using gradient high-performance liquid chromatography with ultraviolet detection (277 nm) and structurally elucidated by liquid chromatography with mass spectrometry. With acetonitrile/5 mmol/L ammonium acetate solution as the eluent and 1 mL/min as the flow rate on a C18 column, the derivatives were eluted at 10.6 and 14.8 min. Good linearity (correlation coefficients > 0.999) and low limits of quantitation (0.6 ppm) were obtained. The recoveries were in the range of 80-115% with relative standard deviation < 5.0%. Finally, the established method was successfully used for the determination of methyl methanesulfonate and ethyl methanesulfonate in methanesulfonic acid.