Apera Instruments WS100 User manual

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WS100 Fluoride/pH Portable Meter Kit
Instruction Manual
APERA INSTRUMENTS, LLC
aperainst.com

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1Overview .........................................................................................................................- 3 -
1.1 Basic Functions .................................................................................................................... - 3 -
1.2 Features of Fluoride Measurement....................................................................................... - 3 -
1.3 Features of pH measurement ............................................................................................... - 3 -
2Technical Parameters ： ...................................................................................................- 4 -
2.1 Fluoride............................................................................................................................... - 4 -
2.2 pH ....................................................................................................................................... - 4 -
2.3 mV ...................................................................................................................................... - 4 -
2.4 Other technical parameters.................................................................................................. - 4 -
3Instrument Description ....................................................................................................- 5 -
3.1 LCD Display.......................................................................................................................... - 5 -
3.2 Operation keys..................................................................................................................... - 5 -
3.3 Data Storage, Recall Data, and Clear Data: ............................................................................ - 6 -
4Fluoride ion concentration measurement .........................................................................- 6 -
4.1 Preparation.......................................................................................................................... - 6 -
4.2 Calibration........................................................................................................................... - 6 -
4.3 Sample Measurement.......................................................................................................... - 7 -
4.4 Parameter Settings............................................................................................................... - 7 -
4.5 Notes................................................................................................................................... - 8 -
5pH Measurement.............................................................................................................- 9 -
5.1 Preparation.......................................................................................................................... - 9 -
5.2 Meter Calibration................................................................................................................. - 9 -
5.3 Sample Measurement........................................................................................................ - 10 -
5.4 Parameter Settings............................................................................................................. - 10 -
5.5 Special Notes ..................................................................................................................... - 13 -
5.6 Self-diagnose Information .................................................................................................. - 13 -
6ORP Measurement.........................................................................................................- 15 -
6.1 Sample Measurement........................................................................................................ - 15 -
7Complete Kit.................................................................................................................. - 15 -
8Warranty.......................................................................................................................- 15 -
9Appendix 1. Fluoride Concentration Conversion Table.....................................................- 16 -

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1 Overview
Thank you for purchasing the Apera Instruments WS100 Fluoride/pH Portable Meter Kit (Hereon
after referred as the meter). This fluoride/pH combo meter is widely used for drinking water,
surface water and other water treatment applications, ideal for both in-field and laboratory testing.
Before using the product, please read this manual carefully before use to help you properly use and
maintain the instrument.
For technical support, please contact us at [email protected] or [phone].
1.1 Basic Functions
◼Automatic calibration and temperature compensation (ATC), data storage, self-diagnostics,
automatic shutdown, low-battery reminder
◼Adopting digital filtering and intelligence to improve the instrument's responsiveness and accuracy
of measurement data, measured value display when stable icon.
◼Meets IP57 Waterproof and dustproof rating, ideal for use under harsh environment.
1.2 Features of Fluoride Measurement
◼Patented structure of the 3-in-1 ion electrode contains: ion-selective electrode, reference electrode, and
temperature electrode. This design generates quick stability, fast response, and is easy to use.
◼no need for stirring or added reagents, directly measuring the ion concentration of fluoride in a quick
and simple manner, directly measure the fluoride concentration with three different units: mg/L,
ppm and pF.
1.3 Features of pH measurement
◼1-3 points of automatic calibration, with calibration icons and self-diagnosis function.
◼Automatic recognition of up to 12 different pH standard buffer solutions, there are three series of
standard buffer solutions to choose from: U.S.A, NIST, and CH.

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2 Technical Parameters：
2.1 Fluoride
Measurement range
0.02 ppm to 1900 ppm
Display units
mg/L, ppm, pF
Accuracy
±0.02 ppm or ±5% of reading (whichever is greater)
Temperature
Compensation Range
(0-80) ℃ (Automatic)
2.2 pH
Measurement range
(-2.00 - 19.99) pH
Resolution
0.1/0.01 pH
Accuracy
± 0.01 pH ± 1 digit
Temperature Compensation Range
(0 - 100) ℃(Automatic)
2.3 mV
Measurement range
-1999 mV – 0 – 1999 mV
Resolution
1 mV
Accuracy
±0.1% FS
2.4 Other technical parameters
Data Storage
800 sets
Storage Content
Numberings, measurements, units of measurement and temperature
Power Supply
AA Battery (1.5VX2)
Size and Weight
Instrument:(65X120X31) mm/180g ; Case:(360X270X76) mm/1.5Kg
Quality and Safety
Certification
ISO9001:2015, CE
IP Rating
IP57 Dustproof and waterproof

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3 Instrument Description
3.1 LCD Display
①—— Parameter mode
②—— Measurement value
③—— Measured value storage and display of numbers, symbols indicate:
M+—Store Measured value
RM - Recall measurement values icon ;
④—— Measurement unit
⑤—— Temperature measurement and unit
⑥—— Smiley face; icon indicates stable readings
⑦—— Instrument calibration indicator
⑧—— Low battery reminder
3.2 Operation keys
3.2.1 — Switch on / off key
3.2.2 — Calibration key
（a）In measurement mode, press this key to enter calibration mode.
（b）In parameter setting mode, press this key to change the number or ON/OFF state.
3.2.3 — Function key
(a) In pH measurement mode, short press this key to change measurement parameters, long press this key
to enter parameter setting mode P1, P2, P3 ……
(b) In fluoride measurement mode, press this key to enter parameter setting mode P1, P2, P3 ……
3.2.4 — Backlight and enter key
(a) In measurement mode, short press (< 1.5s ) to turn the backlight display on or off;
(b) In calibration mode or the parameter setting mode, press this key to confirm, and enter measurement;
(c) In pH measurement mode, press this key to change resolution simultaneously: 0.01→0.1 pH
(d) In ion measurement mode, press this key to change parameter unit: mg/L → ppm → pX
3.2.5 — The combination key of memory storage and recall memory.
（a）In measurement mode, short press this button (< 1.5s) to save the measurement data. Long press this
button (＞2s) to display the stored measurement data.
(b) In parameter setting mode, press this button to change the unit % → mol → g/cm3 → g/L or turn the
meter ON/OFF.

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3.3 Data Storage, Recall Data, and Clear Data:
3.3.1 Data Storage
While in the measurement mode, when the measurement data is stable and the smiley face icon appears, short
press key (＜1.5s), LCD will display “ M+ ” icon and a storage serial, and meanwhile storing all of
the measurement information. It can store up to 300 groups.
3.3.2 Display measurement information
(a) While in the measurement mode, long press (＞2s), meter will display the last stored information,
and the storage number and “RM” icon will appear in the lower right corner of the LCD, and the complete
measurement information. Again short press or meter will in turn display all the saved data.
Hold or to quickly check the data.
(b) In the data displaying mode (there are RM and storage number in the upper right corner of the LCD),
press key to return to measurement mode.
Clear the stored data: In the data displaying mode, press key for 5 seconds, LCD will appear CLr for
2 seconds. It means that all the storage has been eliminated, and returns to measurement mode.
4 Fluoride ion concentration measurement
4.1 Preparation
4.1.1 Press key to power on, connect F501-S fluoride ion electrode (pay attention to inserting
direction), the meter automatically switches to fluoride ion concentration measurement mode.
4.1.2 Hold to change fluoride ion concentration unit from mg/l, ppm to pX , release the button after
selection.
4.1.3 If it is a new electrode or if it is your first time use, activate the electrode by soaking it in 19.00
mg/L calibration solution for 1 hour. For regular usage, soak 10 to 20 minutes to activate it. When the
reading is fully stabilized ( stays on screen), the electrode activation is finished. Then you can
start calibration and measurement. (Please note that the reading during activation is random).
4.2 Calibration
4.2.1 Press , LCD displays 0.19 mg/L, and LCD top right corner CAL and the bottom left L will be
blinking, indicating that the meter has entered the 1st point calibration mode and the calibration
solution is 0.19 mg/l; Rinse the fluoride-ion electrode in distilled or deionized water and shake off the
excess water; dip the electrode into 0.19 mg/L calibration solution, stir gently and let it stand still.
4.2.2 When the reading is stable and icon stays on screen , press key again to finish 1st point
calibration. End and 19.0 mg/L will be displayed after a few seconds. CAL and H will be flickering

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on the screen, indicating the meter has entered the 2nd point calibration mode and the calibration
solution is 19.00 mg/L.
4.2.3 Take out the electrode and shake off excess solution, then dip it into 19.00 mg/L calibration solution,
stir gently and let it stand still. When the reading is stable and stays on screen, press key
again to finish 2nd point calibration. After a few seconds End shows up, indicating the end of
calibration; LCD’left corner shows two-point calibration icons L and H; The instrument automatically
enters measurement mode.
4.3 Sample Measurement
4.3.1 Rinse the fluoride-ion electrode in distilled or deionized water and shake off excess water or blot dry
with filter paper. Soak the electrode into your sample solution, stir gently and let it stand still; get the
measurement when the reading is stable and stays on screen.
4.3.2 Hold to show Fluoride concentrations in different units, release after selection.
4.3.3 Short press key, the meter enters the mV mode and displays the mV value of the fluoride
ion concentration.
4.3.4 After test, rinse off the electrode with distilled water, shake off excess water, and store dry with the
cap on.
4.4 Parameter Settings
Table (4-3)
Symbol
Parameter sets the project
Code
Parameters
P1
Temperature unit selection
˚C / ˚F
P2
Backlight display time setting
0-1-3-6 min
P3
Auto power off time setting
0-10-20 min
P4
Restore to factory default
settings
OFF-ON
4.4.1 Temperature units ° C/ºF selection (P1)
Long Press to enter P1，remaining operations see section 5.4.5
4.4.2 Backlight display time setting (P2)
In P1, long press to enter P2，remaining operations see section 5.4.6

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4.4.3 Auto-off time setting (P3)
In P2, press to enter P3，remaining operations see section 5.4.7
4.4.4 Restore factory default (P4)
In P3, press to enter P4，remaining operations see section 5.4.8
4.5 Notes
4.5.1 The meter does not automatically recognize calibration solutions. Please make sure to use correct
calibration solution according to the displayed reminders "0.19 mg/L" or "19.00 mg/L".
4.5.2 The calibration solution can be easily polluted, especially for low concentration solution (0.19 mg/l).
Please pay attention to avoid contamination otherwise a large measurement error will occur. Replace
the solution after 4~5 times of use.
4.5.3 When storing the electrode, just rinse it out and shake off excess water, then store dry with the
electrode cap on.
4.5.4 When testing solutions in the order from low-concentration to high-concentration, the electrode does
not need to be rinsed. Just shake off excess water or blot dry with filter paper. If it’s from high-
concentration to low-concentration, you need to rinse the electrode with distilled or deionized water,
otherwise it will affect the accuracy significantly.
4.5.5 Typically the meter needs to be calibrated before use every time. But when requirement of accuracy
is low, calibration is not necessary. Or try the electrode in the calibration solution, if the error is very
small, calibration is not necessary.
4.5.6 According to the theory of Isothermal measurements of ion-selective electrode, the smaller the
difference of temperature between test solution and the calibration solution, the higher the
measurement accuracy is. Typically, temperature difference between test solution and calibration
solution should ≤±15℃; for high accuracy measurement, the temperatures should be the same.
4.5.7 When the meter is functioning abnormally, please set P4 as “ON” to reset the meter to factory
default mode, and then perform calibration and measurements again.

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5 pH Measurement
5.1 Preparation
Connect the 201T-S pH Electrode to the meter (pay attention to the inserting direction); loosen the cap of the
storage bottle of electrode; screw off the storage bottle; Press to turn on meter. The meter automatically
switches to pH measurement mode.
5.2 Meter Calibration
5.2.2. Use distilled water to rinse off electrode and then shake off excess water or blot dry with filter paper.
Then soak it into the pH 7.00 buffer solution, stir the electrode gently and let it stand still.
5.2.1. Press to enter calibration mode, LCD displays C1, indicating the first point of calibration; Wait
for a stable reading and to appear and stay, then press again , the LCD will show a
blinking 7.00 pH, indicating the 1st point of calibration is completed; a stable pH value and a
blinking C2 will be displayed, indicating the first point calibration has been finished and the meter
enters the second point of calibration.
5.2.3. Rinse the pH electrode in distilled water and dry it, then soak it into the pH4.00 buffer solution, stir
the electrode gently and let it stand still,, waiting for a stable reading and a smiley face icon to
appear and stay, then again press , the LCD will show a blinking 4.00 pH, a stable pH value
and a blinking C3 will be displayed, indicating the second-point calibration has been finished and
the meter enters the third-point calibration.
5.2.4. Rinse the pH electrode in distilled water and dry it, then soak it into
the pH 10.01 buffer solution, stir the electrode gently and let it stand
still, waiting for a stable reading and a smiley face icon to appear
and stay, then again press , the LCD will show a blinking
10.01 pH. A stable reading and L M H calibration icons will be
displayed, see picture (4-1), indicating the three-point calibration has been finished and the meter
automatically returns to measurement mode.
5.2.5. Notes
(a) This meter can perform one-point, two-point or three-point automatic calibrations. After the first
point calibration (see item 5.2.2.), press to confirm one-point calibration and return to

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measurement mode. The indication icon M standing for one-point calibration will appear on the
lower left corner of LCD. When the requirement of accuracy is ≤±0.1pH, users can perform a one-
point calibration with the pH7.00 buffer solution.
(b) After the second-point calibration, (see item 5.2.3.), press to confirm two-point calibration
and return to measurement mode. The indication icon L and M for two-point calibration will appear
on the lower left corner of LCD. User can choose pH4.00 and pH7.00 to calibrate if the measurement
is within the acidity range and choose pH7.00 and pH10.01 to calibrate if within the alkalinity range.
(c) Users should perform a three-point calibration to reach a more accurate measurement if the
measurement range is wide, or if the electrode has been used for long or has aging phenomenon. If
it’s a new electrode, a three-point calibration is necessary to adjust the meter’s slope to match the pH
electrode.
5.3 Sample Measurement
Soak the pH electrode into the sample solution after rinsing and drying, hold the electrode still. Take
the readings when the smiley face icon shows up and stays on screen (indicates a stable reading).
pH isothermal measurement principle
According to the theory of Isothermal measurements, the smaller the difference of the temperatures
between test solution and the calibration solution, the higher the measurement accuracy is. Typically,
temperature difference between test solution and calibration solution should ≤±15℃; for high
accuracy measurement, the temperatures should be the same.
5.4 Parameter Settings
5.4.1. pH measurement parameter setting (Chart (5-1)
Prompt
Mark
Parameter Setting Items
Code
Parameters
P1
pH buffer solution series selection
SOL
USA(U.S.A series)
NIS (NIST series)
CH (China series)
P2
Purified water pH temperature
compensation setting
PU1
OFF-On
P3
Ammonia added purified water pH
temperature compensation setting
PU2
OFF-On
P4
Temperature unit setting
℃ ℉
P5
Back light display time setting
BL
0-1-3-6min

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P6
Auto power off setting
AC
0-10-20min
P7
Restore to Factory Default
OFF-On
5.4.2. pH buffer solution series selection (P1)
(a) Press key, meter enters P1 mode: see picture (4-2).
(b) Press or key to choose buffer solution series:
⚫U.S.A series —1.68, 4.00, 7.00,10.01 and 12.45 pH
⚫NIST series — 1.68, 4.01, 6.86, 9.18 and 12.45 pH
⚫China series — 1.68, 4.00, 6.86, 9.18 and 12.46 pH
(c) Press key to enter next parameter setting or press key to confirm and return to
measurement mode.
5.4.3. Purified water pH temperature compensation setting (P2)
(a) Short press key in the mode P1, the meter enters mode P2,
see picture (4-3).
(b) Press or to choose ON or OFF.
(c) Press key to enter next parameter setting or press key
to confirm and return to measurement mode.
(d) The default setting is “ OFF ”.
Note: A PU-1 icon will appear in the upper right corner of the LCD if purified water temperature
compensation function is set by the user.
5.4.4. Ammonia added purified water pH temp. compensation setting (P3)
(a) Short press key in mode P2 to enter mode P3, see picture (4-
4).
(b) Press or key to choose ON or OFF
(c) Press to enter next parameter setting or press key to
confirm and return to measurement mode.
(d) The default setting is “ OFF ”.
Note: A PU-2 icon will appear in the upper right corner of the LCD if purified water temperature
compensation function is set by the user.

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5.4.5. Temperature unit ℃/℉ setting (P4)
(a) Short press key in mode P3 to enter mode P4, see picture (4-
5).
(b) Press or key to choose temperature unit: ℃ or ℉.
(c) Press key to enter next parameter setting or press key
to confirm and return to measurement mode.
5.4.6. Backlight display time setting (P5)
(a) Short press key in mode P4 to enter mode P5, see picture (4-
6).
(b) Press or key to choose the time of backlight auto
power off: 0 min, 1 min, 3 min or 6 min. The backlight display
function will be closed if choosing a 0 min.
(c) Press key to enter the next parameter setting or press key to confirm and return to
measurement mode.
(d) The default setting for P5 is 1min.
5.4.7. Auto power off time setting (P6)
(a) Short press key in mode P5 to enter mode P6, see picture (4-
7).
(b) Press or key to choose the time: 0min, 10min or
20min. The auto power off function will be closed if choosing
0min.
(c) Press key to enter next parameter setting or press key to confirm and return to
measurement mode.
(d) The default setting for P6 is 10min.
5.4.8. Restore to default setting (P7)
(a) Short press key in mode P6 to enter mode P7, see picture (4-
8).
(b) Press or key to choose “ON”, means that all the pH
measurement parameters have been restored to the factory default
setting.

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5.5 Notes
5.5.1. The frequency that you need to calibrate your meter depends on the tested samples, performance of
electrodes, and the requirement of the accuracy. For high-accuracy measurements (≤ ±0.02pH), the meter
should be calibrated before test every time; For ordinary-accuracy measurements (≥±0.1pH), once calibrated,
the meter can be used for about a week or longer. In the following cases, the meter must be re-calibrated before
testing:
a) The electrode hasn’t been used for a long time or a new electrode is connected.
b) After measuring strong acid (pH<2) or strong base (pH>12) solutions.
c) After measuring fluoride-containing solution and strong organic solution
d) There is a significant difference between the temperature of the test sample and the temperature of the
buffer solution that is used in the last calibration.
5.5.2. The soaking solution in the supplied protective bottle is used to maintain activation in the glass bulb and
junction. Loosen the capsule, remove the electrode and rinse in distilled water before taking a measurement.
Insert the electrode and tighten the capsule after measurements to prevent the solution from leaking. If the
soaking solution is turbid or moldy, replace the KCL solution (Product# AI1107).
5.5.3. For calibration accuracy, the pH of the standard buffer solution must be reliable. The buffer solution
should be refreshed often, especially after heavy use. We recommend 10-15 times of use before replacing the
pH buffers.
5.5.4. Always keep the meter clean and dry; especially around the socket connecting the meter and electrode,
otherwise it may lead to inaccurate measurements or a damaged probe/meter. To clean, dry them with medical
cotton and rubbing alcohol if the connectors appear dirty.
5.5.5. The sensitive glass bulb at the front of the combination electrode should not contact with hard surfaces.
Scratches or cracks on the electrode will cause inaccurate readings. Before and after each measurement, the
electrode should be rinsed with distilled water and dried. If a sample sticks to the electrode or it’s contaminated,
the electrode should be thoroughly cleaned using a soft brush with soap water and then rinsed with distilled
water. After that, soak it in the KCL solution again for 6 hours.
5.5.6. How to renew the pH electrode when its response is getting slow:
For general contaminants, soak the electrode in Apera’s cleaning solution (AI1166) or detergent water for 30
minutes. Then use a soft brush to remove the contaminants. Afterwards, soak the probe in Apera 3M KCL
soaking solution (AI1107) for at least 1 hour. Rinse it off, then re-calibrate the tester before using.
For other special contaminants, refer to Table-8

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Table-8 Clean contaminated glass bulb and junction
Contamination
Cleaning Solutions
Inorganic metal oxide
Dilute acid less than 1mol/L
Organic lipid
Dilute detergent (weak alkaline)
Resin macromolecule
Dilute alcohol, acetone, ether
Proteinic haematocyte sediment
Acidic enzymatic solution (saccharated yeast tablets)
Paints
Dilute bleacher, peroxide
a) Every pH electrode gradually loses its sensitivity and will eventually fail. The lifespan period for the
201T-S pH Electrode is about 1-2 years depending on how it’s used and maintained.
b) When an abnormal reading appears during calibration or measurement, please set P7 to “ON” to restore
the meter to Factory Default settings, then re-calibrate the meter before measurement.
c) Electrodes that have been used for a long period of time will become aged. Submerge the electrode in
0.1mol/L hydrochloric acid for 24 hours, then rinse the electrode in distilled water, then submerge it in
3M KCL soaking solution for 24 hours. The method to prepare 0.1mol/L hydrochloric acid: dilute 9mL
hydrochloric acid in distilled or deionized water to 1000mL.
5.6 Self-diagnose Information
When using the meter, the following icons might appear. This is the meter’s self-diagnose information, which
helps users identify problems occurring with the meter or the electrode:
a) A still display of -2.00 pH or 19.99 pH — this icon appears when the value has surpassed the measurement
range. There will also appear such signs when the electrode is not well connected with the meter or when
the electrode is not immerged into the solution. This is a normal phenomenon.
b) Err1 — Abnormal electrode zero potential (<-60mV or >60mV)
c) Err2 — Abnormal electrode slope (< 85% or >105%)
When “Err1” or “Err2” appears, the meter cannot work properly, please take the following steps to check
and fix the problem:
a) Check if the electrode bulb has air bubble, if has, please shake the electrode with force for a few times to
eliminate the air bubble inside the sensor.
b) Check the quality of buffer solution, if it is expired or contaminated. If so, please replace with new ones.
c) Set the meter to factory default mode then recalibrate it.
d) If the meter still cannot recover to the normal state after doing the above steps, please replace a new pH
electrode.

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6 ORP Measurement
6.1 Sample Measurement
6.1.1. Press key to turn on, and short press to switch to mV mode;
6.1.2. Connect the ORP probe (301Pt-S, sold separately), soak it into sample solution, stir gently and let it
stand still. Get the readings when the smiley face ion appears and stay on the screen.
7 Complete Kit
WS100 Fluoride/pH meter *1 pc; 201T-S 3-in-1 plastic pH/ATC electrode *1 pc; F501 Fluoride combination
electrode *1pc; pH standard buffer solution (pH 4.00, pH 7.00and pH 10.01, 50mL) *1pc/each; Fluoride
calibration solution (0.19ml/L and 19mg/L, 50mL) *1pc/each; Screw driver *1pc; Spare AA batteries *3pcs;
Operation manual *1pc; Carrying case *1pc
8 Warranty
We warrant this instrument to be free from defects in material and workmanship and agrees to repair or replace
free of charge, at option of APERA INSTRUMENTS, LLC, any malfunctioned or damaged product
attributable to responsibility of APERA INSTRUMENTS, LLC for a period of two years from the delivery (a
six-month limited warranty applies to probes). This warranty does not apply to defects resulting from actions
such as misuse (violation of the instructions in this manual or operations in the manner not specified in this
manual), accidental damage, improper maintenance, or unauthorized repairs. Warranty period is the time limit
to provide free service for the products purchased by customers, not the service life of the tester or probe.

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9 Appendix 1. Fluoride Concentration Conversion Table
APERA INSTRUMENTS, LLC
Address: 6656 Busch Blvd, Columbus, OH 43229 Phone: [phone]
Website: a p e rain st. c om Email: [e-mail]
mol/L
pF
mg/L
ppm
1 ×10-3
3.00
19.00
19.00
1 ×10-4
4.00
1.90
1.90
1 ×10-5
5.00
0.19
0.19