2.2 Analysis of Chemical Composition in Pancreatic...
2.2.1 Chemical Elements in Pancreatic Stones
Calcium is themost abundant chemical element in pancreatic stones（almost 90%）.Other elements such as P，S，K，Fe，Cr，Ni were also found.Pitchumoni et al.（1987）studied the major，minor，and trace elements present in pancreatic stones by DC-plasma emission（DCP）spectroscopy and found that pancreatic stones were made up of calcite and contained，in addition to calcium，17 other elements.They also studied the morphology，nature，and elements in human pancreatic stones by scanning electron microscopy（SEM）and energy dispersive X-ray fluorescence（EDXRF）and found that the amorphous nidus only contained iron，chromium，and nickel，whereas the outer shell was made up of calcium and 17 other elements.(https://www.daowen.com)
2.2.2 Composition of Human Pancreatic Stones
It is important to know how the organic and inorganic components interact with each other during pancreatic stone formation.Calcium carbonate was the major inorganic component in pancreatic stones.The organic matrix of pancreatic stones includes proteins and glycosaminoglycans（mucopolysaccharides and mucosubstances）.Comparing pancreatic stones before and after decalcification，Bockman et al.（1986）found carbonate more common on rounded，lamellar，or otherwise modified surfaces by scanning electron microscopy.They were embedded in a gel-like matrix.Histochemical studies found that the gel-like matrix was made up of acid glycosaminoglycans，acid glycoprotein，and neutral glycoprotein.Farnbacher et al.（2005）found that clogging material in pancreatic stents contained mucopolysaccharides，crystals，and plant material，as well as visible calcium carbonate calculi.