Accurate Determination of Calcium and Chlorine in Food with Inductively Coupled Plasma Tandem Mass Spectrometry

An analytical method for the determination of Ca and Cl elements in food was established with inductively coupled plasma tandem mass spectrometry (ICP-MS/MS). The most abundant isotope Ca-40 of Ca is suffering from intense interferences from the Ar-40 among the argon plasma gas, and Cl-35 is subjected to interference from (OOH)-O-16-O-18. To avoid the interference, in the MS/MS mode, collision/reaction cell (CRC) was adopted using H-2 as the reaction gas, so that H-2 will reach with Ar-40+ instead of Ca-40(+), A H-2 on-mass method was used to eliminate the interference of Ar-40(+) on Ca-40(+). As mass shift reaction could take place between Cl-35(+) and H-2 to generate H-2 Cl-35(+), thus the interference of (OOH+)-O-16-O-18 on Cl-35(+) can be eliminated by determining H-2 Cl-35(+) Ca and Cl showed good linearity in the concentration range of 0. 0 similar to 100. 0 mu g.L-1 with linear correlation coeffiClent (R-2)>= 0. 999 9, and the detection limits of Ca and Cl were 0. 061 and 2. 32 mu g.L-1, respectively. The accuracy and preClsion of this method were verified by series of national standard materials. The results of this method were basically consistent with the certified values of the reference materials, indicating that the method of good accuracy and high preClsion. The new method can be used to achieve the accurate determination of Ca and Cl in food.