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Kennedy/Jenks Consultants <br /> SOG 5: Standard Operating Guideline <br /> _ Field Measurement of pH <br /> 5.1 Introduction <br /> This guideline describes the procedure that will be used by Kennedy/Jenks Consultants personnel <br /> during performance of field pH measurements. <br /> 5.2 Equipment <br /> Portable pH meter with potassium chloride (KCI) probe and temperature probe <br /> • Extra KCI filling solution <br /> • 50 ml plastic jar or other suitable container <br /> • Squirt bottle and supply of deionized (DI) water <br /> • pH 7, 10, and 4 buffer solutions <br /> 5.3 Typical Procedures <br /> 1. Calibrate meter according to manufacturer's instructions. Prior to first measurement, check <br /> calibration against pH 7 buffer and again periodically over the course of the day, and recalibrate <br /> if the reading is more than 0.1 units from 7- <br /> 2. Use 50 ml plastic jar or other suitable containers for measurement readings. Rinse sample test <br /> container with sample water three times prior to measurement. <br /> 3. Immerse pH probe and temperature electrode in sample water. Gently stir sample for thorough <br /> mixing. Read and record pH to nearest 0.1 unit once pH reading has stabilized. Many pH <br /> meters possess an automatic feature which indicates final stabilized measurement. <br /> 4. Rinse or bathe pH and temperature probes with DI water or soak in DI water between <br /> measurements. Changing DI water bath between measurement stations increases accuracy of <br /> measurements. <br /> 5.4 Instrument Calibration - General Procedure <br /> 1. Calibrate pH meter in the field at the beginning of each day of field work and when the standard <br /> check is out of calibration. <br /> 2. Rinse pH and temperature probes in DI water. <br /> 3. Turn on meter and immerse pH and temperature probe in a pH 7 buffer solution. Calibrate <br /> meter to pH 7, allowing enough time for meter to stabilize. <br /> Groundwater Protection Work Plan, The Wine Group SOG 5 <br /> Franzia Winery, Ripon, California 1 <br /> ` gtisymupbdminVW0T03012002 wing pl0greWsM rVanlappm6cesk15 pM asum.dm <br />