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Ding, SM,Wang, Y,Xu, D,Zhu, CG,Zhang, CS
2013
July
Environmental Science & Technology
Gel-Based Coloration Technique for the Submillimeter-Scale Imaging of Labile Phosphorus in Sediments and Soils with Diffusive Gradients in Thin Films
Published
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Optional Fields
DISSOLVED REACTIVE PHOSPHORUS IN-SITU MEASUREMENT HIGH-RESOLUTION NATURAL-WATERS DGT TECHNIQUE PHOSPHATE SULFIDE LAKE FRACTIONATION PERFORMANCE
47
7821
7829
We report a highly promising technique for the high-resolution imaging of labile phosphorus (P) in sediments and soils in combination with the diffusive gradients in thin films (DGT). This technique was based on the surface coloration of the Zr-oxide binding gel using the conventional molybdenum blue method following the DGT uptake of P to this gel. The accumulated mass of the P in the gel was then measured according to the grayscale intensity on the gel surface using computer. imaging densitometry. A pretreatment of the gel in hot water (85 degrees C) for 5 d was required to immobilize the phosphate and the formed blue complex in the gel during the color development. The optimal time required for a complete color development was determined to be 45 min. The appropriate volume of the coloring reagent added was 200 times of that of the gel. A calibration equation was established under the optimized conditions, based on which a quantitative measurement of P was obtained when the concentration of P in solutions ranged from 0.04 mg L-1 to 4.1 mg L-1 for a 24 h deployment of typical DGT devices at 25 degrees C. The suitability of the coloration technique was well demonstrated by the observation of small, discrete spots with elevated P concentrations in a sediment profile.
DOI 10.1021/es400192j
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