Today, we will learn how to prepare some gold nanoparticles and practice measurements.
- Prepare Stock Solutions
- Prepare AuNPs
- Practice Measurements
Stock Solution Preparations
Before we begin, we must ask ourselves several questions
- How do we know what concentrations to make?
- In which experiments will these solutions be used?
- How accurate must the concentrations be?
- How much will we need?
For this experiment, we want a final solution pH ~ 3.6, use 1 mL or less for 10 mL solution, use storage vessels that are 15 mL or 45 mL, allow for Au:Protein between 10 & 200, prepare 0.5 – 1.0 L of AuNP over course of semester, and minimize waste. You will see how I used these criteria to determine stock solution concentrations tomorrow. For now, just use the target concentrations of 2.5 mM HAuCl4 and 250 μM BSA (Bovine Serum Albumin).
For the gold stock solution you must use Teflon wrapped spatulas.
We will want to produce both gold nanoparticles (as a colloid) and gold-protein fibers. This means we need Au:BSA molar ratios of 80 and 160. We also want to make a total of 10 mL of solution. To keep the 3.6 pH criteria mentioned earlier, we must use 1 mL of HAuCl4. How much BSA will you need? Prepare your solutions as follows:
- Obtain a clean glass test tube
- Add 1 mL of gold solution using a 1 mL pipetter
- Add the appropriate amount of BSA solution using a 200 μL pipetter
- Add enough water to make a total of 10 mL. You can use a combination of pipetters. We have 2 5 mL pipetters available.
- Record your results
- Cover top with foil
- Place in oven at 80 °C for 3 - 4 hr
- Precision & Accuracy of Pipetters
- Table of water densities v temperature
- At least 6 using same pipetter, more than 10 preferred
- Preparing Solutions
- Prepare 100 mL of 1.71 mM NaCl from solid
- Prepare 10 mL of 13.5 μM dye from stock & wet flasks
- Reagent Purities
- Is that CaCl2 really anhydrous? (use either KFT or DSC)
- Is that glassware really clean? (use UV or ISE)
- Is DI water pure? (use ISE, AgNO3, or Cond)