Abstract In the present work, a novel continuous flow system (CFS) is developed for the preconcentration and determination of Cr (VI) using Pseudomonas aeruginosa static biomass immobilized onto an effective and low-cost solid support of powdered eggshells. A mini glass column packed with the immobilized biosorbent is incorporated in a CFS for the preconcentration and determination of Cr (VI) from aqueous solutions. The method is based on preconcentration, washing and elution steps followed by colorimetric detection with 1,5-diphenyl carbazide in sulphuric acid. The effects of several variables such as pH, retention time, flow rate, eluent concentration and loaded volume are studied. Under optimal conditions, the CFS method has a linear range between 10 and 100 μg L-1 and a detection limit of 6.25 μg L-1 for the determination of Cr (VI). The sampling frequency is 10 samples per hour with a preconcentration time of 5 mins. Furthermore, after washing with a 0.1 M buffer (pH 3.0), the activity of the biosorbent is regenerated and remained comparable for more than 200 cycles. Scanning electron microscopy reveals a successful immobilization of biomass on eggshells powder and precipitation of Cr (VI) on the bacterial cell surface. The proposed method proves highly sensitive and could be suitable for the determination of Cr (VI) at an ultra-trace level.

中文翻译：

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铜绿假单胞菌静态生物质固定在蛋壳粉上用于在线富集和测定 Cr (VI)

摘要 在目前的工作中，开发了一种新型连续流动系统 (CFS)，用于使用固定在有效且低成本的蛋壳粉固体载体上的铜绿假单胞菌静态生物质来预浓缩和测定 Cr (VI)。装有固定化生物吸附剂的微型玻璃柱被纳入 CFS，用于从水溶液中预浓缩和测定 Cr (VI)。该方法基于预浓缩、洗涤和洗脱步骤，然后用硫酸中的 1,5-二苯基卡巴肼进行比色检测。研究了几个变量的影响，例如 pH、保留时间、流速、洗脱液浓度和加载体积。在最佳条件下，CFS 方法的线性范围在 10 到 100 μg L-1 之间，检测限为 6.25 μg L-1，用于测定 Cr (VI)。采样频率为每小时 10 个样品，预浓缩时间为 5 分钟。此外，在用 0.1 M 缓冲液 (pH 3.0) 洗涤后，生物吸附剂的活性得到再生，并在 200 多个循环中保持可比性。扫描电子显微镜显示生物质成功固定在蛋壳粉上，Cr (VI) 沉淀在细菌细胞表面。所提出的方法被证明具有高灵敏度，可适用于超痕量水平的 Cr (VI) 的测定。扫描电子显微镜显示生物质成功固定在蛋壳粉上，Cr (VI) 沉淀在细菌细胞表面。所提出的方法被证明具有高灵敏度，可适用于超痕量水平的 Cr (VI) 的测定。扫描电子显微镜显示生物质成功固定在蛋壳粉上，Cr (VI) 沉淀在细菌细胞表面。所提出的方法被证明具有高灵敏度，可适用于超痕量水平的 Cr (VI) 的测定。