tailieunhanh - Molecular Biology Problem Solver 12

Molecular Biology Problem Solver 12. Sách được nhiều nhà khoa học có uy tín, nhiều kinh nghiệm trong nghiên cứu thực nghiệm trình bày những vấn đề thường hay phát sinh trong phòng thí nghiệm. Do vậy mà sách không trình bày các protocol hay quy trình như các sách khác, thay vào đó các tác giả sẽ trình bày các vấn đề nhằm giúp giúp đọc giả: Tự nâng cao khả năng chẩn đoán nguyên nhân khi gặp các vấn để về kỹ thuật, quy trình, hóa chất, thuốc thử trong quá trình thực nghiệm trong phòng thí. | What Are the Options for Cleaning Cuvettes Dirty cuvettes can generate erroneous data as they can trap air bubbles or sample carryover. Cuvettes made from optical glass or quartz should be cleaned with glassware detergent or dilute acid . HCl up to concentrations of M but not alkalis which can etch the glass surface. When detergent is insufficient first inspect your cuvette. If it is comprised of a solid block of glass or quartz and you see no seams within the cuvette you can soak it in concentrated nitric or sulfochromic acids but not HF for limited periods of time. Then the cuvettes must be rinsed with copious amounts of water with the aid of special cell washers ensuring continuous water flow through the cell interior. Exposure to harsh acid must be of limited duration due to the possibility of long-term damage to the cuvette surface. Alternatively polar solvents can also be employed to remove difficult residues. One cuvette manufacturer claims to provide a cleaning solution that is suitable for all situations Hellmanex Hellma Southend . . Seams are indicative of glued joints and are more commonly present in low sample volume cuvettes. The interior sample chambers of seamed cuvettes can be treated with acid but not the seams. Cuvettes made from other materials or mixtures with glass should be treated with procedures compatible their chemical resistance. How Can You Maximize the Reproducibility and Accuracy of Your Data Know Your Needs Must your data be absolutely or relatively quantitative If your situation requires absolute quantitation your absorbance readings should ideally fall on the linear portions of a standard calibration curve. Dilute your sample if it s absorbance lies above the linear portion or select a cuvette with shorter path length. If your absorbance values reside below the linear portion and you can t concentrate your samples include additional calibration standards to the original standard curve that are similar to your concentration