Abundant vanadyl (VO) and nickel (Ni) porphyrins were detected in the Late Devonian–Early Mississippian Woodford formation shales using a recently developed reverse-phase liquid chromatography quadrupole time-of-flight mass spectrometry with electrospray ionization (RPLC-ESI-qTOF-MS) method. This Woodford shale sequence is characterized by the presence of sustained photic zone euxinia (PZE), as indicated by the occurrence of green sulfur bacteria-produced isorenieratane. The distribution of VO- and Ni-porphyrins, expressed as the VO/(VO + Ni) ratio, reflects a generally reducing/sulfidic condition throughout most of the Woodford deposition. However, in the later Upper Woodford, there is a significant drop in the VO/(VO + Ni) ratio, marking the collapse of anoxia/euxinia due to gradual oxygenation. The depth profiles of VO- and Ni-porphyrin concentrations exhibit a remarkable increase during the peak of PZE in the Middle Woodford, implying that Ni-porphyrin is not completely limited by sulfide. All three categories of porphyrin structures, namely bicycloalkanoporphyrin (BiCAP), deoxophylloerythroethioporphyrin (DPEP), and etioporphyrin (Etio), occurred in VO- and Ni-porphyrins. VO²⁺ exhibits a preferential chelation to BiCAP over the other two types of porphyrins. In contrast, Ni-porphyrins are predominantly composed of Etio structures. Due to such selective binding of metal species to specific porphyrin structures, the relative abundance of VO- and Ni-porphyrins (VO/Ni) exhibits a strong positive correlation (R² > 0.83) with the ratio of BiCAP to Etio (BiCAP/Etio). These findings suggest that the distribution of VO- and Ni-porphyrins in sediments is not solely controlled by the availability of metal ions. When both VO²⁺ and Ni²⁺ are not limited, the molecular configurations of porphyrins determine the relative abundance of VO- and Ni-porphyrins. Further investigations into the influence of biological and diagenetic processes on the production of BiCAP and Etio are crucial and warrant future research endeavors.

使用最近开发的电喷雾电离反相液相色谱四极杆飞行时间质谱（RPLC-ESI-qTOF- MS）方法。该 Woodford 页岩层序的特征是存在持续的透光区 euxinia (PZE)，绿色硫细菌产生的异雷尼尔烷的出现表明了这一点。VO-和 Ni-卟啉的分布以 VO/(VO + Ni) 比率表示，反映了伍德福德沉积大部分地区普遍存在的还原/硫化条件。然而，在后期的Upper Woodford，VO/(VO + Ni)比值显着下降，标志着由于逐渐氧化而导致缺氧/常氧的崩溃。VO-和Ni-卟啉浓度的深度剖面在中伍德福德的PZE峰值期间表现出显着增加，这意味着Ni-卟啉并不完全受到硫化物的限制。所有三类卟啉结构，即双环烷卟啉 (BiCAP)、脱氧叶绿红硫卟啉 (DPEP) 和硫卟啉 (Etio)，均出现在 VO- 和 Ni- 卟啉中。与其他两种卟啉相比，VO ^{2+对 BiCAP 具有优先螯合作用。}相比之下，Ni-卟啉主要由 Etio 结构组成。 由于金属物质与特定卟啉结构的这种选择性结合，VO-和 Ni-卟啉的相对丰度 (VO/Ni)与 BiCAP 与 Etio 的比率 (BiCAP/Etio)表现出很强的正相关性 (R 2 > 0.83 ⁾）。这些发现表明沉积物中 VO- 和 Ni- 卟啉的分布不仅仅由金属离子的可用性控制。当VO ²⁺和Ni ²⁺均不受限制时，卟啉的分子构型决定了VO-和Ni-卟啉的相对丰度。进一步研究生物和成岩过程对 BiCAP 和 Etio 生产的影响至关重要，值得未来的研究努力。