UltraBasic Benchtop pH MeterOperation Manual

UltraBasic

S

22.2°C

4.06pH

Denver Instrument

Measuring

44 7 10

UB-5

pH Meter

entermode

setup

standardize

902388.1 Rev. A

1. Connect a AC adapter tothe power connection.

mode enter

setup

standardize

pH

°C

S

4 7 10

UltraBasic

Power RefInput ATC

2. Connect an electrode to the Inputand ATC connectors, if desired.

3. Press mode until the dis-play indicates the appro-priate measurement mode(pH or mV/relative mV).

4. Standardize the meterusing up to three buffersby immersing the elec-trode in a buffer, stirring,then pressing standardizeto enter each buffer.

UltraBasic Meter Quick Reference

5. The display shows the cur-rent reading in pH, mV, orrelative mV units.

6. Press setup to review elec-trode calibration and to clearor select buffer sets.

Table Of Contents

Quick Reference . . . . . . . . . . . . . . . . . . . . . . . . . .Inside Front Cover

Getting StartedFront panel controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3Digital display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3Rear panel connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4

Installing and Maintaining Electrodes . . . . . . . . . . . . . . . . . . . . . .5Installing electrodes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5Storing electrodes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6

Standardizing for pH Measurement . . . . . . . . . . . . . . . . . . . . . . . .7Entering buffers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

Using Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10Clearing Buffers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10Reviewing electrode standardization . . . . . . . . . . . . . . . . . . . . .10Selecting buffer sets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10

Standardizing for Millivolt Measurement(Relative Millivolts) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12

Entering a millivolt standard . . . . . . . . . . . . . . . . . . . . . . . . . . .12Using Setup in mV Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13

Clearing a millivolt standard . . . . . . . . . . . . . . . . . . . . . . . . . . .13Understanding pH Theory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14

Defining pH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14Understanding Temperature Compensation . . . . . . . . . . . . . . . .15Measuring pH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17

Electrode testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17Meter Operation testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18

Meter Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19Technical Assistance . . . . . . . . . . . . . . . . . . . . . . . . . . . Back Cover

1

Disclaimers

Important Note:The operator shall be responsible for any modifications to DenverInstrument Company equipment and for any connections of cablesor equipment not supplied by Denver Instrument and must checkand if necessary, correct these modifications and connections.

You have purchased a quality precision meter that requireshandling with care.

Read entire contents of this Operation Manual prior to operating your new Denver Instrument meter.

Caution: Changes or modifications not expressly approved by the manufac-turer could void the product’s warranty.

Manufactured in the U.S.A. by:

2

mode enter

setup

standardize

pH

°C

S

4 7 10

UltraBasic

1.68 4.01 6.86 9.18 12.46S1 S2 S3

321%/°C

AutoMan

SetClear

OKError

1234567810101213

SalTDS

%DOmg/L

S/cm cm ion rel mV pHmµ

KM

°C

S

Getting Started

3

setup - press toclear buffers,review electrodecalibration orselect new autorecognizedbuffer set.

mode - press totoggle betweenpH or mVmode. (UB-10 only)

Digital Display

StabilityIcon

Temperature

Mode

Front Panel Controls

Result

ElectrodeCheckIcons

Prompts

BufferIcons

enter - pressto selectoptions.

standardize -press to auto-recognizeeach buffer.

Note: Not all icons on display will be used.

MeasuringIcon

StandardizingIcon

Power RefInput ATC

Rear Panel Connectors

Power

Cable

Connector

Reference Electrode

Connector

(used with separate

Reference Electrodes)

BNC

Electrode

Connector

ATC (Automatic

Temperature

Compensation)

Probe

Connector

4

Installing and Maintaining Electrodes

This meter allows you to use:• Combination pH electrode with BNC connector• 3-in-1 combination electrode with BNC connector and 2.5 mm

phone jack for ATC• Indicating pH electrode with BNC connector and sperate reference• Separate 2.5 mm phone jack for ATC• Ion selective or ORP electrode with BNC connector.

5

1. Remove the protective end coverfrom electrode.

3. Remove the shorting cap on the BNC connector. Install the electrode byplugging it into the input connection (push on and twist to lock). Anaccessory ATC probe can be installed in the ATC port for the most accu-rate measurement.

2. Before using your pH electrode,or whenever the electrode isdry, soak over-night in anElectrode Filling Solution, KCIsolution or Electrode StorageSolution.

Power RefInput ATC

Power RefInput ATC

6

4. If a separate reference electrode is used, plug the reference electrodeinto the ref pin.

5. Rinse and blot-dry electrodesbetween each measurement (donot wipe). Rinse electrodeswith distilled water or deionizedwater, or part of the next solu-tion to be measured.

6. Store pH electrodes in KCI solu-tion or Electrode StorageSolution. Always leave the fillinghole open when in use andclosed when in storage. Refillwith Filling Solution when theinternal solution level gets 1”below fill hole.

Reference

Electrode

Note: The electrode that comeswith the UltraBasic kit is gel-filled.It has no fill solution or filling hole.

7

Standardizing for pH Measurement

Because electrodes vary in their response, you must standardize your pHmeter and electrode to compensate for electrode variation. The more fre-quently you standardize, the more accurate your measurements.Standardize daily, or more often, for accurate results.

Note: To escape from standardizing mode, press “Standardize “ key again.

1. Immerse electrode in a buffersolution. Stir gently. Allow theelectrode to reach a stable value.

pH

°C

S

4 7 10

2. Press and release the mode but-ton until your digital displayindicates pH mode.

3. Clear existing buffers when doinga new standardization. Use thesetup and enter buttons to clearexisting buffers.

4. Press standardize. The meterflashes the current buffer setand recognizes the flashingbuffer. When the signal is stable,or when you press enter, thebuffer is entered.

standardize

setup

entermode

Clear

pH

4 7

standardize

setup

entermode

2 4 7 10 12

pH

°C

S

standardize

setup

entermode

8

5. The meter displays the percentslope of the electrode as 100.0%on the first buffer. On entering asecond or third buffer, themeter performs a diagnosticcheck on the electrode and dis-plays the slope.

6. To enter a second buffer, placethe electrode in the secondbuffer solution, stir, allow timefor the electrode to stabilize,and press standardize again.The meter recognizes the buffer.

7. Next, the meter performs adiagnostic test of the electrode.The display indicates electrodecondition. The meter displaysthe % slope of the electrode.

8. Slope Error indicates that yourelectrode is not working proper-ly. The electrode response mustbe between 90 and 105% slope.Measurements causing SlopeError are not accepted, used orstored by the meter. Press enterto continue.

OK

7

pH

S

standardize

setup

entermode

2 4 7 10 12

pH

°C

S

standardize

setup

entermode

Error 4 7

pH

standardize

setup

entermode

OK

4 7

pH

standardize

setup

entermode

9

9. To enter a third standard, placethe electrode in the third buffersolution, stir, allow to stabilize,and press standardize. Theresults will be the same as insteps 7 and 8.

10. After entering each buffer, theStandardizing icon goes off andthe Measuring or Stable iconappears on the display to indi-cate that the meter returns toMeasuring operation.

11. Standardize your meter andelectrode using at least twobuffers with pH values bracket-ing the expected pH of yoursamples. Stirring with a mag-netic stir bar and stirrer pro-vides faster electrode response.

Note: If an ATC probe is used, themeter continually adjusts for tem-perature. Therefore, buffers mayvary slightly from the nominal val-ues because of temperature.Default temperature is 25 oC

Note: The temperature is only dis-played when an ATC probe isattached.

OK

7 10

pH

standardize

setup

entermode

pH

°C

S

4 7 10

standardize

setup

entermode

10

Using Setup in pH Mode

The setup button lets you clear all the buffers/standards that you haveentered, review calibration information, or select the buffer/standard setthat you want.

Note: Continuing to press setup will return you to measurement mode.

1. Press setup and the meter dis-plays a flashing Clear icon. Usethis step only when you wish toclear all buffers you haveentered. To clear all existingbuffers, press enter. The meterclears all buffers and returns toMeasuring screen.

2. Press setup again to show elec-trode performance. If the meterhas accepted two buffers, it willdisplay Good Electrode, displaythe slope between the first andsecond buffers and display thetwo buffer icons.

3. Pressing setup again shows theelectrode slope between thesecond and third buffers (ifthree buffers have beenentered) and shows the secondand third buffer icons.

Clear

pH

4 7

standardize

setup

entermode

OK

4 7

pH

standardize

setup

entermode

OK

7 10

pH

standardize

setup

entermode

Note: These screens will only bedisplayed if buffers are stored.

11

4. Press setup again to display aflashing Set Buffers icon and todisplay the first buffer set (U.S.buffer ser) icons.

5. Press enter to select the set ofbuffers shown on the display

orPress setup again to view thenext set of buffers (Merck bufferset). Continue pressing Setup toview the third buffer set (NISTbuffer set).

Set

2 4 7 10 12

pH

standardize

setup

entermode

Set

1 3 6 8 10 13

pH

standardize

setup

entermode

12

Standardizing for MillivoltMeasurement/ Relative Millivolts(UB-10 Model only)

You use millivolt measurement for electrode diagnostics, titration or mea-suring redox potential (also called ORP, oxidation reduction potential). ORPmeasurements indicate the oxidizing or reducing capability of a solution.You can use ORP values to monitor or control solutions requiring a setamount of oxidants or reductants.1. Immerse electrode in a stan-

dard solution. 2. Press the mode button until

your digital display indicates mVmode.

3. Press standardize to enter a mVstandard and read relative mV.

4. When the signal becomes sta-ble, or when you press enter,the current absolute mV valuebecomes zero relative millivolts.

mV

°C

S

standardize

setup

entermode

mV

°C

S

standardize

setup

entermode

rel mV

°C

S

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setup

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13

1. To clear a mV offset and return toabsolute millivolt mode, presssetup. The meter displays aflashing Clear icon, and showsthe current relative millivolt off-set.

2. To clear the mV standard, pressenter. You then return toabsolute mV mode.

Clear

rel mV

standardize

setup

entermode

mV

°C

S

standardize

setup

entermode

Using Setup in mV Mode (UB-10Model)

14

Understanding pH Theory

Defining pHThe measurement of pH plays an important role in identifying andcontrolling acidity and alkalinity levels for industry and research.pH is a measure of the acidity or alkalinity of a solution and can berepresented by this equation:

pH = -log [H+]

with [H+] representing the concentration of hydrogen ions in thesolution. pH is sometimes referred to as the power of the hydro-gen ion in a solution.

By using a pH meter, you can determine exact pH levels of solu-tions. For example, rather than say that lemon juice is quite acidic,you can say that lemon juice has a pH of 2.4. An exact pH valuecan be used to control or measure acidity levels for manufacturingprocesses or for basic research.

pH values generally range from 0 to 14, with a pH value of 7 beingthe neutral point, or the value of pure water. pH values greaterthan 7 represent increasing alkalinity, whereas pH values below 7represent increasing acidity (Figure 1).

Str

on

g A

cid

Lem

on

Ju

ice

To

mato

Ju

ice

Co

ffee

Pu

re w

ate

r

Bakin

g S

od

a

Am

mo

nia

Str

on

g B

ase

Neutral

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14

more acidic more basicpH

Figure 1.pH Scale showing the relative acidity or basicity

of some common substances.

Understanding TemperatureCompensation

NOTE: Temperature compensation only takes effect when an ATCprobe is attached.

There are two ways that temperature compensation affects pHmeasurement:

1. Buffer pH values change with temperature.Each buffer changes depending on the temperature of the solution.These values are typically found on the label of the buffer. Thetables below are representative of most buffers.

When standardization is performed in pH mode, the pH value isadjusted to the current value for the current temperature.

For example, if your pH 7 buffer isat 20°C the meter will standardizeyour buffer at 7.02 instead of 7.00which is the value at 25°C.

2. The electrode efficiency changeswith temperature.The standard mV change per pHunit is approximately 59.17 at 25°C.However, as shown in the belowgraph, this mV per pH unit valuechanges as temperature changes.

The meter compensates for this change by changing the pH read-ing as temperature changes.

15

U.S. Standard BufferpH 4.00 pH 7.00 pH 10.00

0°C 4.005 7.13 10.345° 4.003 7.10 10.2610° 4.001 7.07 10.1915° 4.002 7.05 10.1220° 4.003 7.02 10.0625° 4.008 7.00 10.0030° 4.010 6.99 9.9435° 4.020 6.98 9.9040° 4.03 6.97 9.8550° 4.061 6.97 9.78

isopotentialpoint

electrodepotential(mV)

500

-500

0

0 7 14

100°C (74mV/pH unit)

50°C (64mV/pH unit)

0°C (54mV/pH unit)

Typical pH electrode response as afunction of temperature

Measuring pH

To measure pH with a conventional glass pH electrode, the meteruses a pH-sensing glass bulb that is sensitive to hydrogen ions.The potential developed at the glass membrane is directly relatedto the pH of the solution.

The glass electrode is paired with a reference electrode which com-pletes the electrical measuring circuit and provides a stable refer-ence point. These two electrodes are joined to create a combina-tion electrode. The combination glass electrode is connected to thepH meter which reads the voltage, converts it to pH units, and dis-plays the result.

PorousJunction

pH Sensor

ATCTemperatureSensor

ReferenceElectrode

16

17

Troubleshooting1. If the signal from the electrode

is out of range, the display willshow “- - -”. This may happenwhen the electrode is not in asolution.

2. The meter will display ElectrodeError when it detects an error inelectrode response. During stan-dardization, the message indi-cates that the electrode is lessthan 90% or more than 105% ofthe correct response. TheElectrode Error message canindicate either a bad electrodeor bad buffer(s).

3. If the meter detects an error inthe temperature probe, the dis-play shows - - -. If you do notuse a temperature probe, themeter uses the default tempera-ture of 25°C .

4. To test the pH electrode, place itin a good pH 7 buffer. Pressmode to use the mV mode, andnote the millivolt reading. Makesure the meter is in mV modeand not relative mV mode.Repeat for either a pH 4 or pH10 buffer. The electrode signalmust be within the limits shownbelow (when temperature isnear 25°C).

Electrode Test

pH 7 0 ± 30 mV

pH 4 159 to 186 mVmore than pH 7

pH10 159 to 186 mVless than pH 7

pH

°C

S

standardize

setup

entermode

Error 4 7

pH

standardize

setup

entermode

pH

°C

S

standardize

setup

entermode

18

5. To test the meter for correct operation, install the BNC (input) shortingcap. Press mode to select the mV mode, and note the mV reading. Makesure the meter is in mV mode and not relative mV mode.If the meterreads 0 + 0.3 mV, it is measuring correctly. Note that a long term drift of0.1mV/month since last calibration is specified.

Power RefInput ATC

19

Accessories

You can order the following accessories for your pH meter:

Replacement UltraBasic pH Electrode 301423.1

Plastic-body pH/ATC Electrode 300728.1

High-performance glass-body 300729.1

pH/ATC Electrode (Tris-compatible)

ATC Temperature Probe 300733.1

Free-standing Electrode Arm with Base 300401.1

Other electrodes, such as ion selective electrodes and redox elec-trodes are also available. Call your sales representative.

Meter Specifications

pH Range 0.00 to 14.00 pHResolution 0.01 pHAccuracy ±0.01 pH

mV (UB-10 only) Range -1800.0 to 1800.0 mVResolution 0.1 mVAccuracy ±0.2 mV or 0.05%,

whichever is greater

Temperature Range 0.0 to 100.0°CResolution 0.1°CAccuracy ±0.2°C

Standardization 1, 2 or 3 buffers

Auto buffer recognition 16 buffers2, 4, 7, 10, 121, 3, 6, 8, 10, 131.68, 4.01, 6.86, 9.18, 12.46

Auto pH Temperature Compensation with ATC probeAutomatic pH electrode slope correction for 90-105%

20

Warranty Instructions

1. Please return the prepaid, pre-addressed Purchase Registration Card toDenver Instrument Company promptly upon your purchase of the DenverInstrument product. The return of the card is not a condition precedent towarranty coverage.

2. If you have any questions about a Denver Instrument product, please con-tact the nearest Denver Instrument office as listed below.

3. If it becomes necessary to return your Denver Instrument product for ser-vice, you must obtain a “Return Authorization Number”. Please pack theproduct securely in its original approved packing carton or an other suitablecontainer. Include your Return Authorization Number on the shipping label.Shipping charges must be fully prepaid.

Return to authorized distributor or :

North and South America: Denver Instrument Company

6542 Fig Street

Arvada, Colorado 80004

1-800-321-1135

Tel: 303-431-7255

Fax: 303-423-4831

U.K. and Ireland: Denver Instrument Company

Denver House, Sovereign Way

Trafalgar Business Park

Downham Market

Norfolk PE38 9SW England

Tel: 44 136 63862 42

Fax: 44 136 63862 04

Europe, Asia and Australia: Denver Instrument GmbH

Robert-Bosch-Briete 10

37079 Gottingen Germany

Tel: 49 551 20977 31

Fax: 49 551 20977 39

North and South America: Denver Instrument Company

6542 Fig Street

Arvada, Colorado 80004

1-800-321-1135

Tel: 303-431-7255

Fax: 303-423-4831

U.K. and Ireland: Denver Instrument Company

Denver House, Sovereign Way

Trafalgar Business Park

Downham Market

Norfolk PE38 9SW England

Tel: 44 136 63862 42

Fax: 44 136 63862 04

Europe, Asia and Australia: Denver Instrument GmbH

Robert-Bosch-Briete 10

37079 Gottingen Germany

Tel: 49 551 20977 31

Fax: 49 551 20977 39

www.denverinstrument.com