LIMONENE QUANTIFICATION BY GAS CHROMATOGRAPHY WITH MASS SPECTROMETRY (GC-MS) AND ITS EFFECTS ON HYDROGEN AND VOLATILE FATTY ACIDS PRODUCTION IN ANAEROBIC REACTORS

The inhibition effect of limonene on the organisms involved in anaerobic reactors may affect obtaining H2 in this process. Rapid and precise limonene quantification is desirable to characterize wastewaters. The objective of this research was to develop a Gas Chromatography Coupled to Mass Spectrometry (GC-MS) method to determine limonene concentration in liquid samples from batch reactors applied to H2 production at 30 ºC. Method validation was carried out through calibration curves (3 to 20 mg L-1of limonene), in addition to evaluating its precision (CV =0.1%), linearity (R2=0.979), limits of detection (1.7 mg L-1) and quantification (4.2 mg L-1). Its inhibitory effect was evaluated with increasing concentrations of limonene (without addition to 2000 mg L-1). Limonene affected the starting time of H2 production (λ), since λ was 8.7 h in control assays and 15 h with 2000 mg L-1 of limonene. The same was observed for obtaining H2, since 19.5 mmol H2 L-1 was obtained in control assays and 8.7 mmol H2 L-1 was obtained in assays with 2000 mg L-1 of limonene. This method was effective for limonene determination in liquid samples from batch reactors and could be used for characterization and control of anaerobic reactors.

柠檬烯（limonene）对厌氧反应器内相关微生物的抑制作用，可能会影响该过程中氢气（H₂）的产出。快速且精准的柠檬烯定量检测，对于废水的特性表征具有重要价值。本研究旨在开发一种气相色谱-质谱联用法（Gas Chromatography Coupled to Mass Spectrometry，GC-MS），用于检测30℃条件下产氢批次反应器液态样品中的柠檬烯浓度。本方法通过校准曲线（柠檬烯浓度范围3~20 mg·L⁻¹）开展验证，并同步评估了其精密度（CV=0.1%）、线性度（R²=0.979）、检测限（1.7 mg·L⁻¹）与定量限（4.2 mg·L⁻¹）。此外，本研究通过梯度递增的柠檬烯浓度（从无添加至2000 mg·L⁻¹）评估了其抑制作用：柠檬烯会影响氢气产出的延滞时间（λ），对照组的延滞时间为8.7 h，添加2000 mg·L⁻¹柠檬烯的实验组则为15 h；氢气产出量也呈现相同趋势，对照组可获得19.5 mmol H₂·L⁻¹，而添加2000 mg·L⁻¹柠檬烯的实验组仅获得8.7 mmol H₂·L⁻¹。该方法可有效检测批次反应器液态样品中的柠檬烯含量，可用于厌氧反应器的特性表征与运行控制。