The determination of accurate protein concentration is a challenge for biopharmaceutical companies when no reference standard is available. ICP-MS is mainly used to analyze metals in a wide range of applications, from environmental analysis to quality control of pharmaceuticals and biopharmaceuticals. However, it can also be used in biotechnology and proteomics [1]. Recently, a remarkable progress that utilizes inductively coupled plasma-mass spectrometry (ICP-MS) as an attractive complement to electrospray MS and MALDI-MS for protein quantification, especially for absolute quantification, has been achieved [2]. In this work, we investigated the occurrence of superoxide dismutase in plant samples. Plant samples were collected from Mazandaran State. The leaves of the selected medicinal plants were washed, air dried and then powdered. The samples were extracted using ultrasonic assisted solvent extraction with water (pH=3). These mixtures were shaken at room temperature for 24 h. After incubation, the extracts were filtered using modified cellulose nanofiber filter based microextraction (CNF-FME). After the extraction Mn was eluted with HNO3 1% and was analysed with Perkin Elmer Sciexe 9000 ICP-MS instrument in full spectrum mode. The developed method can be applied in metabolomics studies. The effect of experimental parameters on the extraction performance including pH, volume and concentration of aqueous solution, pH and volume of eluent solution and amounts of were investigated. Under these extraction conditions, determination by ICP-MS was able to provide a good linearity (R2 ≥0.9997) in the range of 0.1–3400.0 ng mL−1, low limit of detection (0.06 ng mL−1), good extraction repeatabilities (relative standard deviations below 1.5%, n = 10), and enrichment factor of 20. Finally, the developed method was successfully used for the determination of the mentioned analyte in Mints samples. Recoveries in real samples were between 91.2% and 94.7%.
