- Filter 100Ag-LMT (1 week), made on 2013/02/05.
- Create a calibration curve for the determination of Ag+ with a silver ion-selective electrode. Solutions of AgNO3 and KNO3 made on 2013/02/05 were used.
- Test reserved filtrate solution from 95Ag-LMT (24 h).
- During the week that the solution was stirring, the Laponite formed a thick, medium gray gel with the consistency of Neosporin. Half of the gel was reserved for further testing, and the other half was resuspended in (50:50) H2O/EtOH and filtered with 42 Whatman paper. The sample was covered with aluminum foil at all times to prevent photodamage to the silver.
- The sample was left to filter overnight. The next day, 100Ag-LMT was brown in color and was still damp. However, its texture changed to a Jello-like consistency. It was scraped from the filter paper and placed in an aluminum dish in an 80°C oven to dry. The filtrate was reserved for further testing.
Ag+ Calibration Curve
- Beginning with the lowest concentration solution first, place 5 mL in a clean, dry small glass test tube.
- Add 100 μL of 5 M KNO3 as an ionic strength adjustor.
- Stir the solution well, then place the electrode in the solution and measure the mV.
- Repeat the measurement twice more.
- Remove the electrode, rinse it well with deionized water, and blot it dry with Kimwipes.
- Repeat steps 1-5 for all solutions
- The calibration solutions were at the following concentrations of Ag+: 0.0001 M, 0.0010 M, and 0.0105 M. The electrode was stored in 0.0105 M AgNO3 until next needed.