Feasibility study on the development of reference material of pesticide in black tea

In this paper, a study on development of reference material (RM) for α-endosulfan and bifenthrin in black tea as a matrix is reported. The study was conducted on the basis that such RMs was presently not available in Indonesia. To obtain a good and proper RM, a feasibility study of RM development is extremely required. The RM was firstly prepared by grinding the tea leaf to have particle size of about 150-106 μm and water content of about 5.99%. A small portion of the grinded tea leaf was then spiked with hexane solution containing both target analytes at certain concentrations, followed by a proper drying to obtain initial candidate of RM (iCRM). The iCRM was then well-mixed properly with another portion of non-spiked grinded tea material to get final candidate reference material (fCRM) powder. A gas chromatography equipped with electron capture detector was used for analyte identification and the feasibility of the method was evaluated in term of spiking technique and homogenization process. The evaluation by ANOVA showed that fCRM was statistically considered to be homogeneous and having α-endosulfan and bifentrin mass fraction ± U of 380.32 (±120.32) ng g^-1 and 522.74 (±148.65) ng g-1 in dry weight basis, respectively.