School of Chemistry and Centre for Biospectroscopy, School of Chemistry, Monash University, Melbourne, Victoria 3168, Australia.
Analyst. 2012 Aug 21;137(16):3704-9. doi: 10.1039/c2an35289c.
Phosphorus (P) is a major cause of eutrophication and subsequent loss of water quality in freshwater ecosystems. A major part of the flux of P to eutrophic lake sediments is organically bound or of biogenic origin. Despite the broad relevance of polyphosphate (Poly-P) in bioremediation and P release processes in the environment, its quantification is not yet well developed for sediment samples. Current methods possess significant disadvantages because of the difficulties associated with using a single extractant to extract a specific P compound without altering others. A fast and reliable method to estimate the quantitative contribution of microorganisms to sediment P release processes is needed, especially when an excessive P accumulation in the form of polyphosphate (Poly-P) occurs. Development of novel approaches for application of emerging spectroscopic techniques to complex environmental matrices such as sediments significantly contributes to the speciation models of P mobilization, biogeochemical nutrient cycling and development of nutrient models. In this study, for the first time Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) spectroscopy in combination with partial least squares (PLS) was used to quantify Poly-P in sediments. To reduce the high absorption matrix components in sediments such as silica, a physical extraction method was developed to separate sediment biological materials from abiotic particles. The aim was to achieve optimal separation of the biological materials from sediment abiotic particles with minimum chemical change in the sample matrix prior to ATR-FTIR analysis. Using a calibration set of 60 samples for the PLS prediction models in the Poly-P concentration range of 0-1 mg g(-1) d.w. (dry weight of sediment) (R(2) = 0.984 and root mean square error of prediction RMSEP = 0.041 at Factor-1) Poly-P could be detected at less than 50 μg g(-l) d.w. Using this technique, there is no solvent extraction or chemical treatment required, sample preparation is minimal and simple, and the analysis time is greatly reduced. The results from this study demonstrated the potential of ATR FT-IR spectroscopy as an alternative method to study Poly-P in sediments.
磷（P）是富营养化和随后淡水生态系统水质丧失的主要原因。磷向富营养化湖泊沉积物的通量主要以有机结合或生物源的形式存在。尽管多磷酸盐（Poly-P）在生物修复和环境中磷释放过程中的广泛相关性，但对于沉积物样品，其定量分析尚未得到很好的发展。由于使用单一提取剂提取特定 P 化合物而不改变其他化合物存在很大困难，因此当前方法存在明显的缺点。需要一种快速可靠的方法来估计微生物对沉积物磷释放过程的定量贡献，特别是当多磷酸盐（Poly-P）以过量形式积累时。开发用于沉积物等复杂环境基质的新兴光谱技术的新方法，对 P 迁移的形态模型、生物地球化学养分循环以及养分模型的发展有重大贡献。在这项研究中，首次将衰减全反射傅里叶变换红外（ATR-FTIR）光谱与偏最小二乘（PLS）结合使用来定量沉积物中的 Poly-P。为了减少沉积物中如硅等高吸收基质成分，开发了一种物理提取方法，将生物材料从无生命颗粒中分离出来。目的是在ATR-FTIR 分析之前，通过最小的化学变化从沉积物的无生命颗粒中获得最佳的生物材料分离。使用 60 个样本的校准集，在 Poly-P 浓度范围为 0-1mg g(-1) d.w.（沉积物干重）（R(2) = 0.984，预测模型的因子 1 时 RMSEP = 0.041）的范围内，使用 PLS 预测模型可以检测到低于 50μg g(-l) d.w.的 Poly-P。使用这种技术，无需溶剂萃取或化学处理，样品制备最少且简单，分析时间大大缩短。该研究结果表明，ATR FT-IR 光谱作为研究沉积物中 Poly-P 的替代方法具有潜力。
