Various forms of PVC can be achieved by adding thermal stabilizers, plasticizers, antioxidants, fillers and other additives. Additives in PVC enhances its mechanical and thermal properties. In my work, I determined antioxidants in 44 different PVC samples. The method and chromatographic conditions were already optimized. I used C18 reverse phase column and for gradient-elution two mobile phases: acetonitrile and MQ water, the injection volume was 30 μL and flow rate constant at 0.5 mL/min. A wavelength of 210 nm was set on the UV detector. At the beginning, I injected different concentrations of the mixed standard solution of antioxidants and integrated the peak areas in the obtained chromatograms. I plotted a calibration line for each antioxidant - a graph of the peak area of the chromatographic peak of the selected antioxidant as a function of the mass concentration of this antioxidant in the mixed standard solution. Based on obtained results limit of detection and limit of quantification were determined. Then, I prepared the samples for analysis and injected them into the HPLC. Based on the chromatographic peaks, I divided the samples into 6 groups, according to the peaks at the same retention times. I found that, in addition to the antioxidants Irganox 1076 and Irgafos 168, the samples also contain other compounds that could be softened by other antioxidants or other additives.
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