The presence of aquatic biopolymeric organic carbon of high (> 10 - 20 kDa) molecular weight (high-MW OC) in drinking water produced from surface water affects its biological stability which may cause regrowth in disinfectant-free distribution. This study compares two analytical methods for determining the concentration of aquatic high-MW OC, namely LC-OCD (liquid chromatography – organic carbon detection) and PHMOC (particulate and colloidal high-molecular weight OC). LC-OCD entails prefiltration of the water sample, chromatographical separation of the relevant biopolymer (BP) OC-fraction, and in-line OC detection. PHMOC is based on the total OC content of the concentrate obtained after 30 kDa crossflow ultrafiltration of the water sample. LC-OCD BP and PHMOC showed a good linear correlation (R² 0.87) for a suite of treated surface water matrices (except raw water) in the 10 – 200 µg/L concentration range, with PHMOC values being 10% – 30% higher than the corresponding LC-OCD BP value, without a clear impact of other water matrix constituents. The indicative yields and selectivities of both methods for indigenous high-MW OC obtained from the PHMOC concentrate were high (≥ 70 - 88%) but not fully complete, which may explain the observed higher PHMOC values and scatter in the PHMOC – LC-OCD BP correlation. LC-OCD BP and PHMOC displayed similar values and trends across the different seasons and treatment stages, with treated ground water and infiltrated water having the lowest (< 10 µg/L) values. Regrowth (as Aeromonas) levels in disinfectant-free distribution networks corresponded with the high-MW OC concentration in the treated drinking water. Overall, the two methods equivalently quantify the concentration of aquatic high-MW OC. Both methods are suitable for use in biological stability studies. The small sample volume renders LC-OCD more practical, whereas the PHMOC method enables further experimentation and characterization of the high-MW OC fraction.

中文翻译：

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使用 LC-OCD 和 PHMOC 定量分析高分子量有机碳浓度，用于地表水饮用水的生物稳定性研究


地表水产生的饮用水中存在高分子量 （> 10 - 20 kDa） 的水生生物聚合物有机碳 （高 MW OC） 会影响其生物稳定性，这可能导致无消毒剂分布的再生。本研究比较了两种测定水生高分子量 OC 浓度的分析方法，即 LC-OCD（液相色谱 - 有机碳检测）和 PHMOC（颗粒和胶体高分子量 OC）。LC-OCD 需要对水样进行预过滤，对相关生物聚合物 （BP） OC 馏分进行色谱分离，并进行在线 OC 检测。PHMOC 基于对水样进行 30 kDa 错流超滤后获得的浓缩液总 OC 含量。对于浓度范围为 10 – 200 μg/L 的一组处理过的地表水基质（原水除外），LC-OCD BP 和 PHMOC 显示出良好的线性相关性 （R ² 0.87），PHMOC 值比相应的 LC-OCD BP 值高 10% – 30%，没有受到其他水基质成分的明显影响。从 PHMOC 精矿中获得的原生高分子量 OC 的两种方法的指示性产率和选择性都很高 （≥ 70 - 88%），但并不完全，这可能解释了观察到的较高的 PHMOC 值和 PHMOC – LC-OCD BP 相关性中的分散。LC-OCD BP 和 PHMOC 在不同季节和处理阶段表现出相似的值和趋势，处理后的地下水和渗透水的值最低 （< 10 μg/L）。在无消毒剂的分配网络中，再生（如气单胞菌）水平与处理后的饮用水中的高 MW OC 浓度相对应。总体而言，这两种方法等效地量化了水生高 MW OC 的浓度。 两种方法都适用于生物稳定性研究。小样品量使 LC-OCD 更实用，而 PHMOC 方法可以进一步实验和表征高 MW OC 馏分。