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    Combination of high performance liquid chromatography and flame atomic absorption spectrophotometry using a novel nebulizer interface supported T shaped slotted quartz tube for the determination of Vitamin B12
    (Elsevier Science, 2022) Erarpat, Sezin; Bodur, Süleyman; Günkara, Ömer Tahir; Bakırdere, Sezgin
    A novel nebulizer interface (NI) was proposed to combine high performance liquid chromatography (HPLC) and flame atomic absorption spectrophotometer (FAAS). A glass concentric nebulizer was linked to T-shaped slotted quartz tube (T-SQT) using a tubing to transfer the liquid solution eluted from the chromatographic system into the atomization region of FAAS system. T-SQT was also used to intensify the interaction of atoms with the hollow cathode lamp light. Vitamin B12 was selected as an analyte to show the applicability of the new hyphenated system. After optimizing some parameters such as mobile phase flow rate and pH, nebulizer gas flow rate, T-SQT height and injection volume, linear range for the analyte was determined between 4.7 and 92 mg/kg as Co. Limit of detection (LOD) and limit of quantitation (LOQ) for the HPLC-NI-T-SQT-FAAS system were calculated to be 1.6 and 5.3 mg/kg as Co, respectively. Recovery studies were also conducted to verify the accuracy and applicability of the developed method for vitamin tablets and excellent percent recovery results (~ 100%) with low standard deviation values were obtained when matrix-matching calibration strategy was performed for each vitamin tablet. A successful separation and detection of the analyte was achieved within 3.0 min that offers high sample throughput. Two different vitamin tablets were analyzed by the optimized hyphenated system. The developed method also provides low usage of sample solution in contrast to conventional nebulizer in the FAAS system
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    Determination of capsaicin at trace levels in different food, biological and environmental samples by quadruple isotope dilution-gas chromatography mass spectrometry after its preconcentration
    (Elsevier, 2024) Bodur, Sezin Erarpat; Bodur, Süleyman; Ayyıldız, Merve Fırat; Günkara, Ömer Tahir; Dikmen, Yaren; Doru, Esra Sultan; Bakırdere, Sezgin
    Despite the therapeutic properties of capsaicin for some diseases, it shows some side effects for human health. The goal of this study was to develop a precise and accurate analytical strategy for the trace determination of capsaicin in different food, biological and environmental samples including pepper, saliva and wastewater by gas chromatography-mass spectrometry (GC-MS) after spraying-based fine droplet formation-liquid phase microextraction (SFDF-LPME) and quadruple isotope dilution (ID4) method. Acetic anhydride was used as derivatizing agent, and the extraction method was used to enrich the analyte derivative to reach low detection limits. Under the optimum conditions, limit of detection (LOD) and limit of quantitation (LOQ) were determined to be 0.33 and 1.10 mu g/kg, respectively. Percent recoveries calculated for SFDF-LPME-GC-MS method ranged between 84.1 and 131.7 %. After the application of ID4-SFDF-LPME-GC-MS method, percent recoveries were obtained in the range of 94.9 and 104.0 % (%RSD <= 2.8) for the selected samples. It is obvious that the isotope dilution-based method provided high accurate and precise results due to the elimination of errors during the derivatization, extraction and measurement steps.
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    Dispersive solid phase extraction and quadruple isotope dilution–mass spectrometry combination for the accurate and sensitive quantification of capsaicin in pepper, domestic wastewater and human saliva samples by GC–MS system
    (Elsevier Inc., 2025) Bodur, Süleyman; Bodur, Sezin Erarpat; Gürsoy, Selim; Ayyıldız, Merve Fırat; Kartoğlu, Bedrihan; Akbıyık, Hilal; Günkara, Ömer Tahir; Bakırdere, Sezgin
    In the presented study, reduced graphene oxide/Fe3O4 (rGO/Fe3O4) nanocomposites based dispersive solid phase extraction (DSPE) – gas chromatography–mass spectrometry (GC–MS) method was developed for the determination of capsaicin in domestic wastewater (DW), pepper (PP) and human saliva (HS) samples. All important parameters of the DSPE method affected the preconcentration factor were carefully optimized to achieve high signal to noise ratio for the analyte. After the optimization studies, the system analytical performance of DSPE-GC–MS system was evaluated using the aqueous standard solution of capsaicin. Limit of detection (LOD), limit of quantitation (LOQ) and dynamic range were figured out to be 0.54 µg/kg, 1.80 µg/kg and 2.66 – 487.35 µg/kg, respectively. Under the optimum experimental conditions, recovery studies were conducted with the spiked DW, PP and HS samples, and percent recovery results were recorded between 52.6 % and 183.6 % via matrix matching calibration strategy. After the implementation of ID4 strategy, percent recovery results for the spiked DW, PP and HS samples were calculated as 98.2 %–99.3 %, 99.7 %–100.7 % and 99.4 %–99.8 %, respectively. In addition, capsaicin content in Sivri (S)-PP, Kıl (K)-PP and Samandağ (SA)-PP samples were found to be 309.5 ± 11.8 mg/kg, 873.7 ± 26.7 mg/kg and 165.3 ± 5.1 mg/kg via DSPE-GC-ID4-MS method, respectively. As a result, the combination of quadruple isotope dilution (ID4) strategy and the DSPE-GC–MS method were successfully performed to boost the accuracy and precision of developed DSPE-GC–MS method. © 2024 Elsevier B.V.