固相萃取-离子对液相色谱法测定保健品中的叶酸

建立了一种快速、准确、灵敏的固相萃取- 离子对反相高效液相色谱测定保健品中叶酸的方法。用Chromabond-SB 萃取小柱富集保健品中的叶酸,以四丁基溴化铵为离子对试剂,优化了色谱条件。采用 Lu-Na C18色谱柱(250mm × 4.6mm,5μm),SPD-6AV 紫外可见吸收检测器,流动相为0.05mol/L KH2PO4-0.01mol/L 四丁基溴化铵- 乙腈(88:2:10,V/V),用磷酸调节 pH5.5,流速 1.0ml/min,检测波长284nm。结果表明：叶酸在0.06～2.40μg/ml 浓度范围内,峰面积和浓度呈良好的线性关系,相关系数为0.9996,最小检出限为0.008μg/ml,加标回收率为 95.14%～102.87%。     

Effects of La~（3＋） on osteogenic and adipogenic differentiation of primary mouse bone marrow stromal cells

In order to elucidate the action of La3+ on bone metabolism,effects of La3+ on the osteogenic and adipogenic differentiation of pri-mary mouse bone marrow stromal cells(BMSCs) were studied by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide(MTT) test,alkaline phosphatase(ALP) activity measurement,mineralized function,oil red O stain and measurement.The results showed that La3+ pro-moted the proliferation of BMSCs except at 1×10-10 and 1×10-6 mol/L.The effect of La3+ on the osteogenic differentiation depended on con-centrations at the 7th day,but the osteogenic differentiation was inhibited at any concentration at the 14th day.La3+ promoted the formation of mineralized matrix nodules except at 1×10-8 and 1×10-5 mol/L.La3+ inhibited adipogenic differentiation except at 1×10-10 and 1×10-7 mol/L at the 10th day,and inhibited adipogenic differentiation except at 1×10-9 mol/L at the 16th day.These findings suggested that La3+ might have protective effect on bone at appropriate dose and time.This would be valuable for better understanding the mechanism of the effect of La3+ on bone metabolism.