该文建立液相色谱-稳定同位素比值质谱联用(liquid chromatography-stable isotope ratio mass spectrometry,LC-IRMS)检测抗坏血酸δ^(13)C值的分析方法,用于鉴别针叶樱桃粉中抗坏血酸天然来源的真实性。样品中抗坏血酸经液相色谱在线...该文建立液相色谱-稳定同位素比值质谱联用(liquid chromatography-stable isotope ratio mass spectrometry,LC-IRMS)检测抗坏血酸δ^(13)C值的分析方法,用于鉴别针叶樱桃粉中抗坏血酸天然来源的真实性。样品中抗坏血酸经液相色谱在线分离纯化,优化后色谱条件为:Syncronis C18(250 mm×4.6 mm,5μm)色谱柱,流动相为水-pH 2的硫酸溶液(90∶10,体积比),流速0.250 mL/min,色谱柱温度30℃,进样量10μL,通过LC-IsoLink实现目标物全部氧化为CO_(2)气体,最终以气态形式进入稳定同位素质谱仪,直接检测样品中抗坏血酸的δ^(13)C,该方法结果稳定、准确。分别测定了7个合成来源的维生素C片和19个针叶樱桃粉,结果表明,天然来源抗坏血酸δ^(13)C值为-25.00‰~-22.01‰,合成来源抗坏血酸δ^(13)C值为-11.74‰~-10.28‰,两者分布显著性差异,该方法可用于抗坏血酸产品标识的真实性鉴别研究。展开更多
A simple and precise method for direct determination of molar ratio of 206Pb/ 204Pb, 207Pb/ 204Pb and 208Pb/ 204Pb by ICP-MS was developed. The data acquirement parameters of MS for Quadrupole setting time(QST), Dwell...A simple and precise method for direct determination of molar ratio of 206Pb/ 204Pb, 207Pb/ 204Pb and 208Pb/ 204Pb by ICP-MS was developed. The data acquirement parameters of MS for Quadrupole setting time(QST), Dwell time(DT), Integrated time and number of sweeps were investigated in detail. The relative standard deviation(RSD) of different Pb isotope ratios were less than 0.32%[n=5, ρ(Pb)=20 ng/mL]. The mass discrimination and dead time of detector was calibrated by using NIST981 solution. The mass bias factor(α) of 206Pb/ 204Pb, 207Pb/ 204Pb and 208Pb/ 204Pb were 0 002 5, 0 002 9 and 0 002 0, respectively. The dead time of detector was 7 ns. The proposed method has been applied to the analysis of geological standard reference materials containing AGV-1, BCR-2 and BHVO-2 .The relative error between this work and the recommend values or reported values was better than 0.73% and the relative standard deviation was better than 0.93%(n=5).展开更多
This paper presents The investigation of laser resonance ionization mass spectroscopy of lutetium with our laser ionization mass spectrometry system manufactured by our own. The optimum radius of laser focal spot over...This paper presents The investigation of laser resonance ionization mass spectroscopy of lutetium with our laser ionization mass spectrometry system manufactured by our own. The optimum radius of laser focal spot overlapped with atomic beam is calculated theoretical.Lutetium ionic signal at The rate of 1.8 ×105 s- 1is detected The Sample she of 1 μg lutetium.. With laser resonance ionization and The of atomizer,it is possible that The detection ho reaches 106 atoms. The effect of laser-induce isotopic discrimination on The measurement of isotope ratio is discussed. It is proposed that laser bandwidth and wavelength tuning effects are The main factors of deviation of lutetium isotopic ratios with this broad bandwidth laser.展开更多
该研究建立了一种精准测定不同样品中氨基酸含量及其氮同位素组成的方法。首先利用N-新戊酰基-O-异丙酯(NPP)对氨基酸进行衍生化,使其更适用于气相色谱分析。随后,采用气相色谱-质谱(GCMS)对大豆、土壤以及标准样品中的15种氨基酸单体...该研究建立了一种精准测定不同样品中氨基酸含量及其氮同位素组成的方法。首先利用N-新戊酰基-O-异丙酯(NPP)对氨基酸进行衍生化,使其更适用于气相色谱分析。随后,采用气相色谱-质谱(GCMS)对大豆、土壤以及标准样品中的15种氨基酸单体进行定量分析,所有目标氨基酸均获得良好的分离效果,且在1.0~16.0μmol/L浓度范围内呈线性关系(r^(2)>0.98)。此外,利用气相色谱-燃烧-同位素比值质谱(GC-C-IRMS)对上述样品中氨基酸的氮同位素组成(δ~(15)N)进行了测定。结果表明,当进样量超过20 ng N([N_(2)^(+)]m/z 28信号强度约为150 mV)时,该方法可以获得稳定可靠的δ^(15)N值,平均精度可达0.36‰。通过与元素分析-同位素比值质谱(EA-IRMS)的结果进行比较,两种方法的测定结果高度一致(r^(2)=0.9954),表明NPP衍生化过程未引入明显的氮同位素分馏。最终测得大豆和土壤样品中各氨基酸的δ~(15)N值分别分布在10.90‰~22.32‰和-1.92‰~12.82‰之间,标准偏差分别为0.23‰~0.88‰和0.08‰~0.79‰,符合样品分析的精度要求。展开更多
文摘A simple and precise method for direct determination of molar ratio of 206Pb/ 204Pb, 207Pb/ 204Pb and 208Pb/ 204Pb by ICP-MS was developed. The data acquirement parameters of MS for Quadrupole setting time(QST), Dwell time(DT), Integrated time and number of sweeps were investigated in detail. The relative standard deviation(RSD) of different Pb isotope ratios were less than 0.32%[n=5, ρ(Pb)=20 ng/mL]. The mass discrimination and dead time of detector was calibrated by using NIST981 solution. The mass bias factor(α) of 206Pb/ 204Pb, 207Pb/ 204Pb and 208Pb/ 204Pb were 0 002 5, 0 002 9 and 0 002 0, respectively. The dead time of detector was 7 ns. The proposed method has been applied to the analysis of geological standard reference materials containing AGV-1, BCR-2 and BHVO-2 .The relative error between this work and the recommend values or reported values was better than 0.73% and the relative standard deviation was better than 0.93%(n=5).
文摘This paper presents The investigation of laser resonance ionization mass spectroscopy of lutetium with our laser ionization mass spectrometry system manufactured by our own. The optimum radius of laser focal spot overlapped with atomic beam is calculated theoretical.Lutetium ionic signal at The rate of 1.8 ×105 s- 1is detected The Sample she of 1 μg lutetium.. With laser resonance ionization and The of atomizer,it is possible that The detection ho reaches 106 atoms. The effect of laser-induce isotopic discrimination on The measurement of isotope ratio is discussed. It is proposed that laser bandwidth and wavelength tuning effects are The main factors of deviation of lutetium isotopic ratios with this broad bandwidth laser.
文摘该研究建立了一种精准测定不同样品中氨基酸含量及其氮同位素组成的方法。首先利用N-新戊酰基-O-异丙酯(NPP)对氨基酸进行衍生化,使其更适用于气相色谱分析。随后,采用气相色谱-质谱(GCMS)对大豆、土壤以及标准样品中的15种氨基酸单体进行定量分析,所有目标氨基酸均获得良好的分离效果,且在1.0~16.0μmol/L浓度范围内呈线性关系(r^(2)>0.98)。此外,利用气相色谱-燃烧-同位素比值质谱(GC-C-IRMS)对上述样品中氨基酸的氮同位素组成(δ~(15)N)进行了测定。结果表明,当进样量超过20 ng N([N_(2)^(+)]m/z 28信号强度约为150 mV)时,该方法可以获得稳定可靠的δ^(15)N值,平均精度可达0.36‰。通过与元素分析-同位素比值质谱(EA-IRMS)的结果进行比较,两种方法的测定结果高度一致(r^(2)=0.9954),表明NPP衍生化过程未引入明显的氮同位素分馏。最终测得大豆和土壤样品中各氨基酸的δ~(15)N值分别分布在10.90‰~22.32‰和-1.92‰~12.82‰之间,标准偏差分别为0.23‰~0.88‰和0.08‰~0.79‰,符合样品分析的精度要求。
