prepared material? Will chemical stabilizers interfere with the research now or in the future? Periodic control assays of material stored over a long term might prove helpful If the sample is subject to minimal batch-to-batch variation during preparation, then multiple small samplings may be the most convenient approach, for this provides an additional benefit of providing fresh sample If you can verify or control for the long-term stability of your sample, large-scale sample preparations are usually preferred since most samples reflect the state of their source at the time that they are obtained Quality Generally speaking, samples of high purity require much more starting material, so one approach to controlling demand on sample quantities is to establish the requisite levels of purity for your application. Many assays and experiments have some degree of tolerance for impurities and will work well with samples that are only moderately pure. If you test the usefulness of different mple purities in your research, you might uncover opportunities to reduce the required amount of sample Are You on schedule? You will likely be asked for precise estimates of when you plan to complete your work, or for time points of certain research mile stones. The answers to the previous questions should provide you with the big picture of the research and how the individual parts could affect one another. An accurate sense of the overall timing of the research ahead should follow This is also a good point to search your memory, or that of a colleague who has done similar work, to identify potential pitfalls. The goal is to eliminate surprises that tend to get you off schedule Which Variables Require Controls? Consider the converse question: Which variables don't require controls? You might have to switch sample origins, reagents, reagent manufacturers, or instrumentation. As discussed in Chapter 2, Getting What You Need from a Supplier, suppliers don,t always notify the research community of every modification to a commercial product. Even control materials require their own controls. As mentioned above, you ll want to have proof that your large quantity of frozen control material is not degrading with Preparing for Success in the Laboratoryprepared material? Will chemical stabilizers interfere with the research now or in the future? Periodic control assays of material stored over a long term might prove helpful. If the sample is subject to minimal batch-to-batch variation during preparation, then multiple small samplings may be the most convenient approach, for this provides an additional benefit of providing fresh sample. If you can verify or control for the long-term stability of your sample, large-scale sample preparations are usually preferred, since most samples reflect the state of their source at the time that they are obtained. Quality Generally speaking, samples of high purity require much more starting material, so one approach to controlling demand on sample quantities is to establish the requisite levels of purity for your application. Many assays and experiments have some degree of tolerance for impurities and will work well with samples that are only moderately pure. If you test the usefulness of different sample purities in your research, you might uncover opportunities to reduce the required amount of sample. Are You on Schedule? You will likely be asked for precise estimates of when you plan to complete your work, or for time points of certain research mile￾stones. The answers to the previous questions should provide you with the big picture of the research and how the individual parts could affect one another. An accurate sense of the overall timing of the research ahead should follow. This is also a good point to search your memory, or that of a colleague who has done similar work, to identify potential pitfalls. The goal is to eliminate surprises that tend to get you off schedule. Which Variables Require Controls? Consider the converse question: Which variables don’t require controls? You might have to switch sample origins, reagents, reagent manufacturers, or instrumentation. As discussed in Chapter 2, “Getting What You Need from a Supplier,” suppliers don’t always notify the research community of every modification to a commercial product. Even control materials require their own controls. As mentioned above, you’ll want to have proof that your large quantity of frozen control material is not degrading with Preparing for Success in the Laboratory 7