Hanna Instruments HI 4115 User Manual

HI 4115

SILVER/SULFIDE

COMBINATION

HI 4015

SILVER/SULFIDE

Instruction Manual

HI 4015HI 4015

HI 4015

HI 4015HI 4015 HI 4115HI 4115

HI 4115

HI 4115HI 4115

Silver/Sulfide Ion

Selective Electrode

Half-cell Combination

HI 4015 Silver/ Sulfide Half-cellHI 4015 Silver/ Sulfide Half-cell

HI 4015 Silver/ Sulfide Half-cell

HI 4015 Silver/ Sulfide Half-cellHI 4015 Silver/ Sulfide Half-cell HI 4115 Silver/ Sulfide CombinationHI 4115 Silver/ Sulfide Combination

HI 4115 Silver/ Sulfide Combination

HI 4115 Silver/ Sulfide CombinationHI 4115 Silver/ Sulfide Combination ElectrodeElectrode

Electrode

ElectrodeElectrode

I. I.

Introduction:Introduction:

Introduction:

I. I.

Introduction:Introduction: The Hanna HI 4015 and HI 4115 are ion selective electrodes designed for the measurement of Silver/ Sulfide ions in aqueous solutions. The HI 4015 is a solid state half-cell sensor that requires a separate reference. The HI 4115 is a combination ion selective electrode.

IIII

SpecificationsSpecifications

II.

Specifications

IIII

SpecificationsSpecifications

Type: Solid State electrode with

a Silver/ Sulfide pellet.

Ion(s) measured: Silver (Ag+), Sulfide (S2-)

Measurement range: Silver 1.0 M to 1 X 10

-6

(107,900 to 0.11 ppm)

Sulfide 1.0 M to 1 X 10

-7

(32,100 to 0.003 ppm)

Theory of OperationTheory of Operation

III. III.

Theory of Operation

III.

Theory of OperationTheory of Operation

III. III.

:: The HI 4015 or HI 4115 Silver/ Sulfide electrodes are potentiometric devices used for the rapid determination of free silver or sulfide ions. They can be used as an indicator following the progress of a halide titration with silver nitrate. Sulfide ion determinations are made in ground waters, soils and paper liquors. The electrode functions as a sensor or ionic conductor. The HI 4015 requires a separate reference electrode to complete its electrolytic circuit. The HI 4115 has a double junction reference electrode incorporated in its design. The silver/ silver- sulfide pellet is practically insoluble in the test solutions being measured and produces a potential change due to changes in the sample’s ion activity. When the ionic strength of the sample is fixed by the addition of ISA, the voltage is proportional to the concentration of silver or sulfide ions in solution and the electrode follows the Nernst equation.

E= E

+ 2.3 RT/nF log A

ion

E= observed potential

Ea= Reference and fixed internal voltages

Interfering ions: Mercury must be absent.

Ions that complex with measured species will reduce measured ion concentrations.

Operating Temperature: 0-80°C

Operating pH: 2-8 pH (For Silver)

12-14 pH (For Sulfide)

Dimensions: 12 mm (OD) X 120 mm

nominal insertion (0.47” X 4.72”)

Connection: BNC

R= gas constant (8.314 J/K Mol)

n= Charge on ion (2- for sulfide), (1+ for silver)

A i=ion activity in sample

T= absolute temperature in K

F= Faraday constant (9.648 x 10

C/mol)

IV. IV.

Design elements of the HI 4015 and HI 4115Design elements of the HI 4015 and HI 4115

IV.

Design elements of the HI 4015 and HI 4115

IV. IV.

Design elements of the HI 4015 and HI 4115Design elements of the HI 4015 and HI 4115

electrodeselectrodes

electrodes

electrodeselectrodes

Cap

HI 4015

SILVER/SULFIDE

Sensor Handle

V. Equipment required:V. Equipment required:

V. Equipment required:

V. Equipment required:V. Equipment required:

• Hanna HI 5315 Double Junction Reference Electrode

with HI 7072 Fill Solution for use with HI 4015.

• Hanna HI 4222 pH/ISE/mV meter or other suitable

ion or pH/mV meter. (Note: log/linear graph paper is useful if an ISE (ion) meter is not available).

• Hanna HI 180 Magnetic Stirrer or equivalent with

Teflon coated stirring bars (HI 731320). (Note: isolate beakers from stirrer motor heat by placing insulating material such as foam or cork between them).

• Hanna HI 76404 Electrode Holder or equivalent.

• Plastic beakers (HI 740036P) or other suitable mea-

surement vessel.

Sensing Membrane

Upper Cap

Upper Threads

O-Ring

Ceramic Junction on Inner Stem

Liquid junction

Spring

Fill Hole

O-Ring and Plug

Outer Sleeve

Sensing Membrane

VI. VI.

Solutions Required for CalibrationSolutions Required for Calibration

VI.

Solutions Required for Calibration

VI. VI.

Solutions Required for CalibrationSolutions Required for Calibration Select appropriate Hanna Instruments standard and ISA from the list below:

0.1 M Silver Standard, 500 mL HI 4015-01 ISA for Silver measurement, 500 mL HI 4000-00 SAOB for Sulfide measurement, 500 mL HI 4015-00 Note: For Sulfide standard, see directions that follow.

Silver Standards For Molar solutions: Using volumetric pipettes and glassware make serial dilutions of HI 4015-01 to approximately bracket the concentration of the samples. Standards with concentrations

-3

< 10

M should be prepared daily. Store in dark plastic bottles. Two mL of Hanna ISA for Halide electrodes (HI 4000-00) should be added to 100 mL of sample or standard. For ppm solutions: Prepare 1078.7 ppm Silver standard by diluting HI 401501: Pipette 100 mL standard to a 1 liter volumetric flask. Add deionized water to volume. Using additional pipettes and glassware make serial dilutions of this 1078.7 ppm standard to bracket the sample concentra-

tions. Standards with concentrations < 100 ppm should be made daily.

Solutions for Sulfide Measurements SAOB, Hanna HI 4015-00 : Add content of SAOB reagent B bottle to the bottle with SAOB reagent A. Cap bottle and mix well until completely dissolved. Reagent that is brown has been oxidized and should be discarded.

Sulfide Standards: Sulfide standards are susceptible to air oxidation and therefore are not commercially available. Sulfide stock solution: Weigh approximately 100 gram of reagent grade Sodium Sulfide nonahydrate (Na2S·9H2O) into a 1 liter volumetric flask that contains a volume of distilled or deionized /deareated water. Swirl to dissolve, bring to volume, then transfer to a tightly sealed 1 L container with minimal head space and allow solution to equilibrate overnight.

133.5 ppm standard (approximate concentration): Transfer 5.00 mL stock solution and 250 mL Sulfide Antioxidant buffer SAOB (Hanna HI 4015-00) to a to 500 mL volumetric flask. Mix well then bring to volume with distilled or deionized /deareated water. Hanna HI 4015-00 SAOB, should be clear to pale straw in color after mixing. Note: higher concentrations of standard can also be prepared and titrated if samples are greater in concentration. The sensor is useable from 32,100 to

0.003 ppm. Determine exact concentration of the prepared standard by doing a titration with Lead Perchlorate standard (user prepared) on a weekly basis. The exact concentration of the standard is found by titrating 10 mL of the standard with 0.01 M Lead Perchlorate standard; (Pb(ClO4)2 ). Pb2++ S

> PbS Use the electrode pair as an indicator for S2- to determine the endpoint. See Section XII.

Calculate as follows: Weekly standard in Molar concentration

= Volume of the standard sulfide solution used

s. s.

C (moles/liter)= (0.01) *

(10 mL) VV

= Volume of the Lead Perchlorate titrant used to reach

t t

/ V

endpoint (mL)) Weekly standard in ppm C (ppm)= (0.01) *32.07

/ V

Using volumetric pipettes and glassware make dilutions daily from the titrated standard whose value has been determined. Choose standards to bracket the concentration of the samples. 50 mL of HI 4000-00 ISA should be added to each 100 mL flask of standard before being brought to volume.

VIIVII

General GuidelinesGeneral Guidelines

VII.

General Guidelines

VIIVII

General GuidelinesGeneral Guidelines

• Calibration standards and sample solutions should

have the same ionic strength. ISA or SAOB should be added to both samples and standards in the same ratio.

• Calibration standards and sample solutions should

be at same temperature.

• Thermally insulate beaker with standard or sample

from magnetic stirrer.

• Calibration standards and sample solutions should

be stirred at the same rate using identically sized TFE coated stir bars.

• Rinse electrode pair with distilled or deionized water

between samples and gently dab off using soft disposable absorbent toweling. Do not rub sensor surface.

• Presoaking silver sensor in a dilute standard

(<10-3M) will help to optimize response.

• A scratched, pitted, or tarnished pellet surface can

cause drift, poor repeatability or a loss of low level response. Restore optimum response can be by removing the damaged surface with the microabrasive strip HI 4000-70.

+ 7 hidden pages