Determination of As, Hg and Pb in herbs using slurry sampling flow injection chemical vapor generation inductively coupled plasma mass spectrometry.
Analysis of herbs for As, Hg and Pb has been carried out using slurry sampling inductively coupled plasma mass spectrometry (ICP-MS) with flow injection vapor generation. Slurry containing 0.5% m/v herbal powder, 0.1% m/v citric acid and 2% v/v HCl was injected into the VG-ICP-MS system for the determination of As, Hg and Pb that obviate dissolution and mineralization. Standard addition and isotope dilution methods were used for quantifications in selected herbal powders. This method has been validated by the determination of As, Hg and Pb in NIST standard reference materials SRM 1547 Peach Leaves and SRM 1573a Tomato Leaves. The As, Hg and Pb analysis results of the reference materials agreed with the certified values. The precision obtained by the reported procedure was better than 7% for all determinations. The detection limit estimated from standard addition curve was 0.008, 0.003, and 0.007 ng mL(-1) for As, Hg and Pb, respectively.
Biosorption of Zn2+, Ni2+ and Co2+ from water samples onto Yarrowia lipolytica ISF7 using a response surface methodology, and analyzed by inductively coupled plasma optical emission spectrometry (ICP-OES)
A response surface methodology (RSM) based on a central composite design with five variables and five levels was employed to interpret the biosorption efficiency of Zn2+, Ni2+ and Co2+ ions onto Yarrowia lipolytica ISF7. Independent variables, viz. pH, temperature, and Zn2+, Ni2+ and Co2+ ion concentrations were transformed into coded values and a quadratic model was built to predict the responses. Analysis of variance (ANOVA) and t-test statistics were used to test the significance of the independent variables and their interactions. The predicted maximum biosorption efficiencies (99.65, 99.30 and 98.78% for Zn2+, Ni2+ and Co2+ ions, respectively) under the optimum recommended conditions (pH 6.0, 25 °C, 30, 25 and 30 mg L−1 of Zn2+, Ni2+ and Co2+ ions) following 24 h mixing were very close to the experimental values (99.65, 99.30 and 98.78% for Zn2+, Ni2+ and Co2+ ions, respectively). The equilibrium equation was extensively investigated and found to be efficiently represented by a Langmuir model with maximum monolayer biosorption capacities of 31.96, 24.40 and 25.77 mg g−1 for Zn2+, Ni2+ and Co2+, respectively. The biosorption data trend closely followed a pseudo-second-order kinetic model. FTIR and scanning electron microscopy coupled with X-ray energy dispersed analysis (SEM-EDX) provided proof of progress of ion biosorption on the yeast surfaces.
Lupin alkaloids from teratogenic and nonteratogenic lupins. II. Identification of the major alkaloids by tandem gas chromatography-mass spectrometry in plants producing crooked calf disease.
The major alkaloids of lupin plants producing crooked calf disease were identified by tandem gas chromatography-mass spectrometry and infrared analysis. The gas chromatography peak invariably present in teratogenic plants proved to be anagyrine. A minor but irregular contaminant of the peak was α-isolupanine. Other alkaloids present but apparently not associated with crooked calf disease were lupanine and two others that were probably epimethoxylupanine and 5,6-dehydrolupanine.