CrCL3, CrNano, Cr piconiate (CrPic) and Cr nicotinate (CrNic) were dissolved to different concentration as 100,200,400,800,1600 ppb in 0.9% NaCl solution.

• 将氯化铬、纳米铬、吡啶羧酸铬和烟酸铬分别配制成5个浓度梯度：100、200、400、800、1000ppb，调节溶液Ph值到8.；5后，测定溶液中铬浓度。