Myron L PH1 - Manual (Page 8)

X. A C C E S S O R I E S
A. Buffer Solutions
pH buffers are available in pH values of 4, 7 and 10. Myron L Company
buffer solutions are traceable to NIST certified pH references and are
color-coded for instant identification. They are also mold inhibited and
accurate to within ±0.01 pH units @ 25°C. Order 4, 7 or 10 buffer.
B. pH Sensor Storage Solution
Myron L Storage Solution prolongs the life of the pH sensor. It is available
in quarts and gallons. Order SSQ or SSG.
C. Soft Protective Case
Padded Cordura ® Nylon carrying case features a belt clip for hands-free
mobility. Order Model: UCC ® Registered trade mark of DuPont
D. Replacement pH Sensor
Model RPG is gel filled and features a unique porous liquid junction. It is
user-replaceable and comes with easy to follow instructions.
E. Conductivity/TDS Standard Solutions
For your other Myron L instruments, our NIST standard solutions are
available in a variety of salts and concentrations to fit your needs. Call or
write for information.
XI. pH MEASURING
A. pH as an Indicator
pH is the measurement of Acidity or Alkalinity of an aqueous solution. It is
also stated as the Hydrogen Ion activity of a solution. pH measures the
effective, not the total, acidity of a solution.
A 4% solution of acetic acid (pH 4, vinegar) can be quite palatable, but a
4% solution of sulfuric acid (pH 0) is a violent poison. pH provides the
needed quantitative information by expressing the degree of activity of
an acid or base.
In a solution of one known component, pH will indicate concentration
indirectly. However, very dilute solutions may be very slow reading, just
because the very few ions take time to accumulate.
B. pH Units
The acidity or alkalinity of a solution is a measurement of the relative
availabilities of hydrogen (H ) and hydroxide (0H ) ions. An increase in
12 13
+ -
Possible Cause
Corrective Action Replace pH sensor (ref. Sensor Replacement, pg. 10) 1. Recalibrate instrument. 2. Thoroughly rinse sensor well. 3. Recalibrate using fresh buffers. (ref. Buffer Solutions, pg. 13 ) Clean and rejuvenate sensor (ref. Cleaning Sensor, pg. 10) and recalibrate. If no improvement, replace pH sensor (ref. Sensor Replacement, pg. 10).
1. pH calibration needed. (ref. Calibration Procedure, pg. 7) 2. Cross-contamination from residual pH buffers or samples in sensor well. 3. Calibration with expired pH buffers.
Symptom
Check connections or replace battery. (ref. Battery Replacement, pg. 10).
Inaccurate
pH
readings
No response to
pH
changes
Will not adjust down to
pH
7.
pH
readings drift or respond
slowly to changes in buffers/samples. No
display
, even though
measurement key pressed.
Battery weak or not connected. Sensor bulb is cracked or an electro- mechanical short caused by an internal crack. pH sensor has lost KCl. 1. Temporary condition due to “memory” of solution in pH sensor well for long periods. 2. Bulb dirty or dried out. 3. Reference junction clogged or coated.
Clean and rejuvenate sensor (ref. Cleaning Sensor, pg. 10) and recalibrate. If no improvement, replace pH sensor (ref. Sensor Replacement, pg. 10).
IX
.
TROUBLESHOOTING CHART