Purification and Calibration of Indicators for Measurement of Seawater pH

海水 pH 测量指示剂的纯化和校准

• 批准号: 0727082
• 负责人: Robert Byrne
• 金额: $ 59.82万
• 依托单位: University of South Florida
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-09-15 至 2012-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0727082&HistoricalAwards=false
• 关键词: Purification; Calibration; Indicators; Measurement; Seawater

It is highly probable that the ever-increasing atmospheric CO2 from fossil fuel burning will lead to substantial global warming (IPCC, 2007). A less-discussed aspect of rising atmospheric CO2 is ocean acidification. A recent reoccupation (2006) of a 1991 North Pacific transect along 152 W revealed pH changes in the upper 200 meters of the water column on the order of 0.025 pH units (Byrne et al., in prep). Such changes are important because pH has a very strong influence on solution speciation and bioavailability, surface chemistry (including that of living cells), mineral solubility (including that of calcareous organisms), and oxidation and reduction kinetics. With on-board precision on the order of 0.0004 pH units, spectrophotometric measurements offer a quick and precise means of monitoring acidification on both short and long-term scales. Since 1990 spectrophotometric pH measurements have been widely used in oceanic and estuarine pH analysis. However due to the presence of impurities, at variable concentrations in indicator dyes, the calibrations of pH indicators can become unreliable. Depending on the source (manufacturer) of an indicator, impurities can cause pH differences as large as 0.01 units. As such, comparison of seawater pH results obtained from different labs is rendered problematic. In this project, researchers at the University of South Florida will characterize the impurities of different pH indicators and purify the indicators. The purified indicators will serve as standard reference materials and will be made available to the research community. Purified indicators will be carefully re-characterized experimentally (measurements of equilibrium constants and molar absorbance ratios) to provide truly calibration-free measurements. Publication of the optimal purification procedures will allow researchers to purify their own indicators. Use of calibrated pH reference materials will also allow researchers to correct data that had been obtained previously with impure reagents. In terms of broader impacts, this project will feature graduate student education as a key priority. The USF College of Marine Science has a strong record of innovative minority participation in graduate student research and education. The principal investigator serves as principal advisor to two minority students. The College of Marine Science has outreach programs for both high school students and undergraduates. The PI has successfully involved participating undergraduate students in both research and publication. The proposed project will also promote opportunities for minority students, undergraduate students, and graduate students.

化石燃料燃烧的不断增长的大气二氧化碳很可能会导致全球变暖（IPCC，2007年）。大气二氧化碳升高的一个不太讨论的方面是海洋酸化。最近对1991年北太平洋沿152 W的重新占领（2006）揭示了水柱上200米的pH变化在0.025个pH单位的阶面（Byrne等人，在PREP中）。这样的变化很重要，因为pH对溶液形成和生物利用度，表面化学（包括活细胞的化学），矿物溶解度（包括钙质生物的溶解度）以及氧化和还原动力学具有非常强大的影响。在0.0004 pH单元的登机上精度，分光光度测量值可快速，精确地监测短期和长期尺度上的酸化。自1990年以来，分光光度法测量已广泛用于海洋和河口pH分析中。但是，由于杂质的存在，在指示剂染料中浓度可变的情况下，pH指示器的校准可能变得不可靠。根据指标的来源（制造商），杂质会导致pH差异为0.01单位。因此，从不同实验室获得的海水pH结果比较是有问题的。在这个项目中，南佛罗里达大学的研究人员将描述不同pH指标的杂质并净化指标。纯化的指标将用作标准参考材料，并将提供给研究社区。纯化的指标将经过实验重新审计（平衡常数和摩尔吸光度比的测量值），以提供真正的无校准测量。最佳纯化程序的发布将使研究人员能够净化自己的指标。使用校准的pH参考材料还将允许研究人员纠正先前使用不纯试剂获得的数据。在更广泛的影响方面，该项目将以研究生教育为重点。 USF海洋科学学院在研究生研究和教育方面有创新的少数群体参与的良好记录。首席调查员是两名少数族裔学生的首席顾问。海洋科学学院为高中生和本科生提供了外展计划。 PI已成功地参与了研究和出版物。拟议的项目还将为少数族裔学生，本科生和研究生提供机会。