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)• 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: CalibrationContinuous:• 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!!!