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International Humic标准品代理
IHSS于1981年9月11日在美国科罗拉多州丹佛市成立，旨在汇集煤炭、土壤和水科学领域对腐殖物质感兴趣的科学家。IHSS拥有近900名科学家。在促进科学教育和研究以及促进公众对腐殖物质的了解方面，学会被gong认为世界领dao者。IHSS的座右铭是：“推进土壤和水中天然有机物的知识和研究"。该协会的目标包括建立和维持从褐煤、淡水、矿物土壤和有机土壤中收集腐殖酸和黄腐酸的标准样品，以及收集表征数据。此外，协会还增加了作为研究腐殖物质来源的参考样品。IHSS每两年召开一次国际会议，汇聚来自土壤、煤炭、淡水和海洋科学的科学家。这些会议由主要科学家与IHSS委员会合作召开。
International Humic标准品代理
，International Humic产品列表：
| Cat. No. | Source | Carboxyl | Phenolic | Q1 | Log K1 | n1 | Q2 | Log K2 | n2 | N | RMSE | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sources: (1) School of Earth & Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, U.S.A.; (2) Department of Chemistry, Environmental Sciences Ph.D. Program, Ball State University, Muncie, IN, U.S.A. | ||||||||||||
| References: (1) J. D. Ritchie and E. M. Perdue, Geochim. Cosmochim. Acta, 67, 85-96 (2003); (2) S. J. Driver and E. M. Perdue, Advances in the Physicochemical Characterization of Dissolved Organic Matter: Impact on Natural and Engineered Systems, American Chemical Society, 1160: 75-86 (2014). | ||||||||||||
| Solutions containing 0.36 ± 0.01 g L-1 (on a dry ash-free basis) of an IHSS sample in 0.1 M NaCl were titrated from their initial pH values of 3.0-3.3 to final pH values of 10.5-10.7 in 25-35 minutes, using 6-8 mL increments of carbonate-free 0.100 M NaOH. All titrations were conducted under a N2 atmosphere in a thermostated water bath at 25.00 ± 0.02 °C. At least three titrations were obtained for each sample. The stock solutions of soil, peat, leonardite, and Summit Hill humic acids also contained 0.002 M NaOH, which was needed to effectively disperse/dissolve those samples, and an equivalent quantity of HCl that was added just before a titration was started. | ||||||||||||
| Carboxyl is the charge density (meq/g C) at pH 8.0; Phenolic is two times the change in charge density (meq/g C) between pH 8.0 and pH 10.0. | ||||||||||||
| The overall charge density (in meq/g C) of a humic substance increases systematically with pH (or with the concentration of H+). The equation on the right, known historically as a modified Henderson-Hasselbalch equation for two classes of binding sites, was used to fit titration data and obtain the set of model fitting parameters in this table. |  | |||||||||||
| The fitting parameters of the model were obtained by a nonlinear least-squares fit of the model to aggregated sets of replicate titration data. Q1 and Q2 are the maximum charge densities of the two classes of binding sites, Log K1 and Log K2are the mean log K values for proton binding by the two classes of sites, and n1 and n2 are empirical parameters that control the width (in log K) of a class of proton binding sites. N is the number of fitted titration data points, and RMSE is the root mean-square error for fitting this model to the data (see Reference). This model, also known in more recent literature as a Langmuir-Freundlich equation, is the primary building block of the NICA class of models. | ||||||||||||
| An * means that a sample is no longer available, and nd means that an item was not determined. | ||||||||||||
| Standard HA | ||||||||||||
| Suwannee River I * | 1S101H | (1) | 9.59 | 4.24 | 10.69 | 4.42 | 3.79 | 2.28 | 9.68 | 1.11 | 113 | 0.0673 |
| Suwannee River II | 2S101H | (1) | 9.13 | 3.72 | 9.74 | 4.35 | 3.30 | 4.48 | 10.44 | 1.73 | 171 | 0.0815 |
| Elliott Soil | 1S102H | (1) | 8.28 | 1.87 | 8.90 | 4.36 | 3.16 | 0.85 | 9.80 | 1.00 | 169 | 0.0943 |
| Pahokee Peat | 1S103H | (1) | 9.01 | 1.91 | 9.64 | 4.22 | 3.20 | 0.94 | 9.86 | 1.00 | 145 | 0.0865 |
| Leonardite | 1S104H | (1) | 7.46 | 2.31 | 8.17 | 4.59 | 3.32 | 1.13 | 9.72 | 1.31 | 106 | 0.0532 |
| Standard FA | ||||||||||||
| Suwannee River I | 1S101F | (1) | 11.44 | 2.91 | 12.00 | 3.80 | 3.21 | 1.48 | 9.52 | 1.00 | 109 | 0.1053 |
| Suwannee River II | 2S101F | (1) | 11.17 | 2.84 | 11.66 | 3.76 | 3.24 | 2.05 | 9.84 | 1.45 | 123 | 0.1072 |
| Elliott Soil I * | 1S102F | (1) | nd | nd | nd | nd | nd | nd | nd | nd | nd | nd |
| Elliott Soil II | 2S102F | (1) | 13.24 | 2.27 | 14.12 | 3.67 | 3.62 | 0.74 | 9.53 | 1.00 | 111 | 0.1375 |
| Pahokee Peat I * | 1S103F | (1) | 13.34 | 2.32 | 14.22 | 3.99 | 3.33 | 0.76 | 9.57 | 1.00 | 117 | 0.1028 |
| Pahokee Peat II | 2S103F | (1) | nd | nd | nd | nd | nd | nd | nd | nd | nd | nd |
| Reference HA | ||||||||||||
| Suwannee River * | 1R101H | (1) | nd | nd | nd | nd | nd | nd | nd | nd | nd | nd |
| Pahokee Peat | 1R103H | (1) | 8.87 | 2.05 | 9.54 | 4.26 | 3.25 | 1.01 | 9.85 | 1.00 | 117 | 0.0773 |
| Nordic Lake | 1R105H | (1) | 9.06 | 3.23 | 10.32 | 4.32 | 4.22 | 1.64 | 9.89 | 1.11 | 105 | 0.0740 |
| Summit Hill Soil | 1R106H | (1) | 7.14 | 2.42 | 7.53 | 4.47 | 3.12 | 1.31 | 9.23 | 1.57 | 106 | 0.0480 |
| Waskish Peat | 1R107H | (1) | nd | nd | nd | nd | nd | nd | nd | nd | nd | nd |
| Reference FA | ||||||||||||
| Suwannee River | 1R101F | (1) | 12.23 | 3.11 | 12.94 | 3.81 | 3.36 | 1.60 | 9.62 | 1.00 | 115 | 0.1312 |
| Pahokee Peat * | 1R103F | (1) | 15.24 | 1.78 | 16.25 | 3.73 | 3.54 | 1.31 | 10.74 | 1.00 | 129 | 0.1586 |
| Nordic Lake | 1R105F | (1) | 11.16 | 3.18 | 12.15 | 3.79 | 3.95 | 1.49 | 9.67 | 1.00 | 107 | 0.1121 |
| Waskish Peat | 1R107F | (1) | nd | nd | nd | nd | nd | nd | nd | nd | nd | nd |
| Pony Lake FA | 1R109F | (2) | 7.09 | 1.75 | 6.91 | 4.52 | 1.92 | 1.43 | 9.48 | 1.77 | 1256 | 0.0340 |
| Aquatic NOM | ||||||||||||
| Suwannee River I | 1R101N | (1) | 9.85 | 3.94 | 10.57 | 3.94 | 3.60 | 2.61 | 9.74 | 1.19 | 112 | 0.0725 |
| Suwannee River II | 2R101N | (2) | 11.21 | 2.47 | 11.20 | 4.16 | 3.44 | 1.60 | 9.99 | 1.03 | 1705 | 0.1360 |
| Nordic Lake | 1R108N | (1) | nd | nd | nd | nd | nd | nd | nd | nd | nd | nd |
| Upper Mississippi River | 1R110N | (2) | 12.43 | 0.83 | 12.51 | 3.47 | 2.69 | 0.91 | 10.00 | 1.00 | 1626 | 0.0800 |
| Bulk Materials | ||||||||||||
| Elliott Soil | BS102M | (1) | nd | nd | nd | nd | nd | nd | nd | nd | nd | nd |
| Pahokee Peat | BS103P | (1) | nd | nd | nd | nd | nd | nd | nd | nd | nd | nd |
| Leonardite | BS104L | (1) | nd | nd | nd | nd | nd | nd | nd | nd | nd | nd |
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