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Analyze-Immediately Parameters. pH. Analyze Immediately. Within 15 minutes of collection: pH Residual Chlorine Temperature Chlorine Dioxide Dissolved Oxygen (probe) Sulfite note sample collection & analysis times!!!. Topics covered today:. pH Temperature Dissolved Oxygen (DO)
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Analyze Immediately Within 15 minutes of collection: • pH • Residual Chlorine • Temperature • Chlorine Dioxide • Dissolved Oxygen (probe) • Sulfite note sample collection & analysis times!!!
Topics covered today: • pH • Temperature • Dissolved Oxygen (DO) • Residual Chlorine (TRC or CPO)….
pH: what we will cover…. • Significance of pH. (data quality) • Points to Remember. • Lab Chemicals. • Good Lab Practices (GLP). • Review NJAC Regs. as they pertain to the recording & reporting of data.
What exactly is pH??? • Negative log of Hydrogen ion activity. • pH above 7: alkaline or basic. • pH below 7: acidic. • pH = 7 is considered neutral. • Di-ionized water saturated with CO2 has pH = 5.65
Data Quality : “a piece a cake!” • Properly working instrument & clean apparatus. • Fresh buffers and reagent rinse water. • Hold times met. • Correctly calibrated. • Proper sample handling. • GLP
Data Quality: Calibration Grab: • Daily, within 3 hrs. of sample analysis. • 2 buffers, bracketed. • Mid-range check. • Record time, concentration and actual reading of each. • For initial calibration, reading must be +/- 0.05 of true value. • Recalibrate if difference is greater than +/- 0.2 (applies to 3 hr. check). • Discard pH buffer aliquots after each use.
Data Quality: Calibration Continuous: • Weekly, unless otherwise stated by SA. • Indirect Calibration - basically a grab (as close to electrode as possible); measure within 15 minutes with lab pH meter; compare readings of continuous monitor with lab pH meter. Record info in logbook, sign & date. • Direct Calibration (as in grab procedure). - accurate to 0.1, per method (SM 4500-H B). • Record time, concentration and actual reading of each. • Discard pH buffer aliquots after each use.
Make sure……. • Grab pH: meter in good working order (field or hand-held models vs.lab or bench-top models). • Continuous monitor: keep probe clean. • Calibrate as per method. • Maintain calibration & sample collection log. • Maintain field data notebook.
Make Sure (continued)- • Discard buffers IMMEDIATELY following use - DO NOT re-use! • Discard expired buffers! • Electrode is OK - not damaged. • Stir or swish sample during measurement. • Record time of analysis.
Make Sure (continued)- • Meters must have accuracy of +/- 0.05 and +/- 0.05 resolution • ...since pH is temperature-dependent • Must be temperature-compensated… • or use stand-alone thermometer…
Lab Chemicals…... • FRESH buffers! (purchase ready-made or make yourself). • Reagent water. • Electrode filling solution (if necessary).
Hold Times • Pertains to grab pH and indirect calibration for continuous measurement. • 0 - 15 minutes - note time of collection & time of analysis!
Good Lab Practices (GLP) • Data signed, initialed & dated. • Instrument ID & serial number • NO pencil! • NO white-out! • Single-line, date & initial all errors.
Analyze-Immediately parameters Records • NJAC 7:18-8.5 - This section pertains specifically to Analyze-Immediately parameters… • GENERAL: retain raw data records, quality control data records, chain-of-custody forms, laboratory reports… • Storage of data - data must be filed & maintained in an accessible location on lab premises for 1 year after analysis date… • Long-term storage: records of analysis must be stored for 5 years after analysis date.
Retain as Records of Analysis • Assigned lab ID # or other form of ID • date & time of analysis • name & signature of person(s) who collected sample • name & signature of person(s) who analyzed sample • type of analysis performed & DSAM* used (*DSAM=Dept. Sanctioned Analytical Method) • results of analysis & raw data generated from analysis
Reporting Results • Certified environmental lab name & NJ lab ID number • date, time & location of sample collection and sample analysis • type of analysis performed and analytical method employed • results from analysis • name & signature of environmental lab manager or designee per NJ regulations (NJAC 7:18-2.11(a)1iii)
Summary • Don’t underestimate the importance of pH. • Adhere to NJAC Regulations and approved method. • Document-document-document!!!