Which Pipette Is Most Appropriate for Your Application? What Are the Elements of Proper Pipetting Technique? 68 Preventing and Solving Problems Troubleshooting PH Meters What Are the Components of a pH Meter? 8777 How Does a pH Meter Function? How Does the Meter Measure the Sample PH? What ls the Purpose of Autobuffer Recognition? Which Buffers Are Appropriate for Your Calibration What ls Temperature Compensation and How Does One Choose the Best Method for an Analysis?........ 84 How Does Resolution Affect pH Measurement? Why Does the Meter Indicate"Ready"Even as the H Value Changes Which PH Electrode Is Most Appropria te for your Analysis? How Can You Maximize the Accuracy and Reproducibility of a ph Measurement? How Do Lab measurements differ from plant or field Does Sample Volume Affect the Accuracy of the PH How Do You Measure the PH of Viscous, Semisolid, Low lonic Strength, or Other Atypical Samples How Can You Maximize the Lifetime of Your pH Meter? Troubleshooting Is the instrument the problem? 92 Service Engineer, Technical Support, or Sales Rep: Who Can Best Help You and at the Least Expens Spectrophotometers What Are the Criteria for Selecting a Spectrophotometer? Beyond the Self-Tests Automatically Performed by Spectrophotomters, What Is the Best Indicator That an Instrument Is Operating Properly Which Cuvette best fits your needs? What Are the Options for Cleaning Cuvettes? How Can You Maximize the Reproducibility and Accuracy f Your data? What Can Contribute to Inaccurate A260 and a280 Data? Troutman et alWhich Pipette Is Most Appropriate for Your Application? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67 What Are the Elements of Proper Pipetting Technique? . . . 68 Preventing and Solving Problems . . . . . . . . . . . . . . . . . . . . . . . 68 Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77 pH Meters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77 What Are the Components of a pH Meter? . . . . . . . . . . . . . 77 How Does a pH Meter Function? . . . . . . . . . . . . . . . . . . . . . . 80 How Does the Meter Measure the Sample pH? . . . . . . . . . 81 What Is the Purpose of Autobuffer Recognition? . . . . . . . . . 82 Which Buffers Are Appropriate for Your Calibration Step? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83 What Is Temperature Compensation and How Does One Choose the Best Method for an Analysis? . . . . . . . . 84 How Does Resolution Affect pH Measurement? . . . . . . . . . 85 Why Does the Meter Indicate “Ready” Even as the pH Value Changes? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85 Which pH Electrode Is Most Appropriate for Your Analysis? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85 How Can You Maximize the Accuracy and Reproducibility of a pH Measurement? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87 How Do Lab Measurements Differ from Plant or Field Measurements? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90 Does Sample Volume Affect the Accuracy of the pH Measurement? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90 How Do You Measure the pH of Viscous, Semisolid, Low Ionic Strength, or Other Atypical Samples? . . . . . . . . . . . . 90 How Can You Maximize the Lifetime of Your pH Meter? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91 Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92 Is the Instrument the Problem? . . . . . . . . . . . . . . . . . . . . . . . 92 Service Engineer, Technical Support, or Sales Rep: Who Can Best Help You and at the Least Expense? . . . . . . . . . 94 Spectrophotometers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94 What Are the Criteria for Selecting a Spectrophotometer? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94 Beyond the Self-Tests Automatically Performed by Spectrophotomters, What Is the Best Indicator That an Instrument Is Operating Properly? . . . . . . . . . . . . . . . . 98 Which Cuvette Best Fits Your Needs? . . . . . . . . . . . . . . . . . . 100 What Are the Options for Cleaning Cuvettes? . . . . . . . . . . 101 How Can You Maximize the Reproducibility and Accuracy of Your Data? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101 What Can Contribute to Inaccurate A260 and A280 Data? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103 50 Troutman et al