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In this study, the Digital Image-Based Colorimetric Detection Method developed by Bakırdere et al. was used to find the TAC (Total Antioxidant Capacity) value of tea samples from different brands. To determine the total amount of antioxidants in tea samples, the CUPRAC (cupric ion reducing antioxidant capacity) method, which is widely used in antioxidant determination, was combined with a digital image-based colorimetric detection system. To use in our study, a box with opaque wood material measuring 24 cm x 19 cm x 17 cm (width/length/depth) was designed and manufactured. In the analysis, the oxidation reaction between the chromogenic copper(II)-neocuproine (Cu(II)-Nc) reagent and antioxidants was utilized. The color change that occurs as a result of the oxidation was calculated using an application on smartphones. In our study, analyzes were performed on 4 different brand tea extract samples (tea A, tea B, tea C, tea D) to determine the total antioxidant capacity of ascorbic acid equivalent. The TAC values for ascorbic acid equivalent in tea extract samples were found as 380 ± 8 mg/L (tea A), 402 ± 4 mg/L (tea B), 213 ± 3 mg/L (tea C), 232 ± 4 mg/L (tea D) using the digital image-based colorimetric detection systems.

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Bu çalışmada, analizi yapılacak numunelerin sıvı-sıvı mikroekstraksiyon ile önderiştirilmelerinin ardından özgün tasarımlı dijital görüntüleme kutusu kullanılarak antimonun(III) kolorimetrik tayinine yönelik yöntem geliştirilmiştir. Önderiştirme aşamasında numune içerisindeki antimon ile kompleks oluşturması amacıyla ditizon ligand olarak kullanılmıştır. Önderiştime işleminden sonra elde edilen renkli örnekler dijital görüntüleme kutusu içerisine yerleştirilmiş ve akıllı telefonlara yüklenebilen bir uygulama kullanılarak kolorimetrik analiz gerçekleştirilmiştir. Analizlere başlanmadan önce dijital görüntüleme kutusu içerisine yerleştirilen kuvars küvetin merceğe olan uzaklığı, kuvars küvet üzerinde kolorimetrik tayinin yapılacağı noktanın konumu ve analiz edilecek noktanın yarıçapına yönelik optimizasyon çalışması yapılmıştır. Optimum koşullar altında farklı derişimlere sahip antimon numelerinin analizi sonucunda 1-4 mg/L aralığında lineer bölge elde edilmiş ve antimon için tayin limiti (LOD) 0,71 mg/L olarak hesaplanmıştır. Çalışmada en düşük konsantrasyon için yüzde bağıl standart sapma %0,33 (n=8) olarak bulunmuştur. Bu değer, yapılan analizin yüksek hassasiyete sahip olduğunu göstermektedir.

In this study, a potentiometric sensor was developed for the analysis of the parahtion which is a nerve agent simulant and pesticide. A molecularly imprinted polymer was used as the recognition layer in the electrode used in the potentiometric sensor. Parathion is also used as both an organophosphorus pesticide and a nerve agent simulant. For this reason, analysis methods to be developed for parathion are very important. The most important advantages brought by MIP-based sensor systems are; fast analysis, sensitive analysis, and the ability to analyze at very low concentrations. The sensor developed in our study was validated for parathion adsorption. In our study, first, Parathion imprinted polymers were synthesized. The synthesized MIPs are used as the recognition layer in the potentiometric sensor. The characterization of parathion imprinted polymers was done by FESEM, FT-IR, and zeta-sizer measurements. Optimization of the working conditions was carried out for the developed sensor system. The working pH was found to be 7.4.Measurements were taken for parathion samples with different concentrations under optimum operating conditions. When the results obtained were examined, a large linear range (10-8-10-4 mol L-1) and a satisfying detection limit against parathion (1.86 × 10-8 mol L-1) were calculated. Interference effect analysis was carried out within the scope of the performance tests of the potentiometric sensor. The analysis showed that interference did not affect the experimental results. In order to examine the matrix effect of the real sample environment, analyses were carried out in tap water and lake water. The recovery values in the analysis results are quite good. The results of the experiments show that the sensor we have developed can be used successfully in complex matrix environments.