Applications include:Total sulfites in foods, dissolved SO₂and H₂S in amine scrubbing solutions, and sulfites in geological materials and wallboard.

The CM440 Total Sulfite, SO₂/H₂S Analyzeris a complete analytical system allowing the direct measurement of total sulfites or dissolved SO₂/H₂S in a wide variety of sample matrices and concentrations. Combining a automated, self-contained unit for the acidification of a sample (to evolve SO₂and/or H₂S), with a highly sensitive SO₂/H₂S detector, the CM440 easily handles solid or liquid samples with concentrations from ppm levels to 100% without user calibration. UICs analyzers are rugged, accurate and adaptable to most applications. They are used extensively in industrial, research and educational laboratories worldwide. The CM440 system includes the following components pictured above:

CM5014S SO2 Analyzer

• No user calibration
• Wide, linear dynamic range
• Readability to 0.01 g Sulfur
• User selectable display units
• Floppy disk drive for archiving data

Instrument Capabilities

A major advantage of the CM440 Total Sulfite, SO₂/H₂S Analyzer is the use of coulometric detection. Employing the principles of Faradays Law, the CM5014S SO₂/H₂S Analyzer automatically measures the absolute mass amount of sulfur dioxide and/or hydrogen sulfide evolved from an acidified sample. No user-calibration is required and linear detection is available from less than 1 g sulfur to over 10, 000 g sulfur. Using this 100% efficient coulometric process, relative standard deviations of 0.2% or better are common for standard material. For smaller concentrations, an absolute deviation of approximately 1 g S is typical.

complete analytical system allowing the direct, simultaneous measurement of TIC and sulfites in a wide variety of sample matrices and concentrations. Combining a self-contained unit for the acidification of a sample (to evolve CO₂, SO₂and H₂S), with a highly sensitive CO₂detector and SO₂/H₂S detector, theCM540 easily handles solid or liquid samples with concentrations from ppm levels to 100% without user calibration. UICs analyzers are rugged, accurate and adaptable to most applications. They are used extensively in industrial, research and educational laboratories worldwide. The CM540 system includes the following components pictured above:

CM5014 CO2 Analyzer and CM5014S SO2/H2S Analyzer

• No user calibration
• Wide, linear dynamic range
• User selectable display units
• Floppy disk drive for archiving data

Instrument Capabilities

A major advantage of the CM540 Simultaneous Carbon/Sulfur Analyzer is the use of coulometric detection. Employing the principles of Faradays Law, the CM5014 CO₂and CM5014S analyzers automatically measures the absolute mass amount of carbon dioxide, sulfur dioxide and hydrogen sulfide resulting from sample acidification. No user-calibration is required and linear detection is available from less than 1 g C/S to over 10, 000 g C/S. Using this 100% efficient coulometric process, relative standard deviations of 0.2% or better are common for standard material. For smaller concentrations, an absolute deviation of approximately 1 g C/S is typical.

Additionally, it is possible to analyze either solid or liquid samples. Sample flasks are available in 10, 25, 50 and 100 ml sizes. Solids or liquids may be weighed directly into the sample flasks. Alternatively, liquid samples may be syringe injected through a septum.

Oxidation times vary with sample type and temperature although 5 to 7 minute analyses are typical. To quicken CO₂and SO₂/H₂S evolution, sample heating and stirring capabilities are included within the CM5130 Acidification Module. Other features include the ability to: select different acids; add wetting/emulsifying agents; and, modify the flow path and scrubbers to optimize a particular application.

The CM320 Total Sulfur Analyzeris a complete analytical system allowing the direct measurement of total sulfur in a wide variety of sample matrices and concentrations. The CM320 consists of a dual zone, high temperature furnace and a sulfur coulometer. The CM320 easily handles solid or liquid samples with concentrations from ppm levels to 100% without user calibration. UICs analyzers are rugged, accurate and adaptable to most applications. They are used extensively in industrial, research and educational laboratories worldwide. TheCM320 system includes the following components pictured above:

CM5017S SO2 Analyzer

• No user calibration
• Wide, linear dynamic range
• User selectable display units
• Floppy disk drive for archiving data

CM5380 Dual Zone Furnace with CM5382 Sample Introduction Kit Programmable up to 1100OC Separate catalyst zone Automated oxygen dosing Split-tube furnace design for easy maintenance Instrument Capabilities A major advantage of the CM320 Total Sulfur Analyzer is the use of coulometric detection. Employing the principles of Faradays Law, the CM5017S SO2/H2S Analyzer automatically measures the absolute mass amount of sulfur dioxide and/or hydrogen sulfide evolved from a combusted sample. No user-calibration is required and linear detection is available from less than 1 g sulfur to over 10, 000 g sulfur. Using this 100% efficient coulometric process, relative standard deviations of 0.2% or better are common for standard reference materials. For smaller concentrations, an absolute deviation of approximately 1 g S is typical.

complete analytical system capable of measuring total sulfur and total sulfites in solid and liquid samples. Combining a dual zone, high-temperature furnace, a self-contained acidification module and a highly sensitive SO₂/H₂S detector, the CM350 offers the flexibility to analyze most any sample type and concentration with a precision un-matched by other analytical techniques. The CM350 system includes the following 3 components pictured above:

CM5014S SO2 Analyzer

• No user calibration
• Wide, linear dynamic range
• Readability to 0.01 g Sulfur
• User selectable display units
• Floppy disk drive for archiving data

CM5380 Dual Zone Furnace with CM5382 Sample Introduction Kit

• Programmable up to 1100OC
• Separate catalyst zone
• Automated oxygen dosing
• Split-tube furnace design for easy maintenance

CM5130 Acidification Module

• 10, 25, 50 or 100 ml reaction vessels
• Selectable volume acid dispenser
• Internal air pump with flow controller
• Controlled sample heating and stirring

Instrument Capabilities

A major advantage of the CM350 Total Sulfur / Total Sulfites Analyzer is the use of coulometric detection. Employing the principles of Faradays Law, the CM5014S SO2/H2S Analyzer automatically measures the absolute mass amount of sulfur dioxide and/or hydrogen sulfide evolved from a combusted sample. No user-calibration is required and linear detection is available from less than 1 g sulfur to over 10, 000 g sulfur. Using this 100% efficient coulometric process, relative standard deviations of 0.2% or better are common for standard reference materials. For smaller concentrations, an absolute deviation of approximately 1 g S is typical.

Sample sizes can range from 0.5mg to 10 grams with concentrations from 1ppm to 100%. Analysis times of 5-7 minutes are typical

TheCM5390Sis used in conjunction with UICs CM5120 or CM5300 high-temperature furnaces and either the CM5011, CM5012, CM5014 or CM5017 coulometer to provide an improved method of sample introduction.

TheAutomated Boat Inlethas a large, easy to access sample entry box, user selectable sample entry speeds, variable purge time setting and an integrated flowmeter. The CM5390S replaces the traditional dog houses and breech block assemblies found on UICs standard analytical systems.

EASY TO USE

The CM5390S eliminates the need to remove and replace breech block caps to insert and retrieve sample ladles. This also eliminates the chance of breaking any sample ladles.

Simply weigh out your sample, place it into the sample entry box, close and latch the lid, and start the analysis. The system is automatically purged of atmospheric CO2, the sample is then automatically introduced, analyzed and retracted* with no user input. Samples can now be analyzed with, literally, one hand tied behind your back.

*When used with a CM5014 or CM5017 coulometer

Carbon Analyzer is a complete analytical system capable of measuring total carbon, total organic carbon and total inorganic carbon in solid andor liquid samples. Combining a high-temperature combustion furnace, self-contained acidification module and a highly sensitive CO2 detector, the CM150 offers the flexibility to analyze most any sample type and concentration with a precision un-matched by other analytical techniques.

In order to align the height of the combustion tube and the breech block, ceramic tube insulation (CM162-016) must be placed around the tube at the furnace ends. It is important to note that each furnace requires a slightly different amount of insulation to align the tube with the breech block. The proper amount of bedding is the amount of insulation necessary to align the combustion tube without applying strain on the tube when mounted in the breech block and the furnace top is closed.Build up the combustion tube bedding from the bottom until the combustion tube is slightly above the breech block opening with the breech block in its lowest position. Periodically check the tube bedding is not built up excessively by gently closing the furnace top.Loosen the pedestal base thumbscrew and tighten the pedestal base onto the rail by turning the base clockwise.

This procedure is typically utilized for the analysis of amine solutions that are used to remove environmentally controlled emissions from flue gases. This method measures the amount of carbon dioxide (CO₂) and the amount of hydrogen sulfide (H₂S) in the scrubbing solution. This result is used along with other analyses to determine the amine scrubbing solutions efficiency and remaining capacity. This procedure may also be used for the analysis of sour water.

The system is composed of the CM5330 Acidification Module and the CM5016 C/S Coulometer. The Acidification Module is purged of atmospheric CO₂, SO₂and H₂S with an inert carrier gas. After purging the system, an aliquot of the amine solution is injected into the sample flask. Acid is then added using the dispenser on the Acidification Module. The gases evolved from the acidification of the sample then pass into the special cell on the Sulfur analysis side of the coulometer where SO₂and H₂S are absorbed into the solution and titrated.

CO₂is not absorbed into the sulfur detector solution and provides no interference. The CO₂enriched carrier gas is then routed to the cell on the Carbon analysis side of the instrument where it is absorbed and automatically titrated.

APPARATUS

CM5016 C/S CoulometerCM5330 Acidification ModuleSpecial, air-tight sulfur cellCarbon cell

REAGENTS

1. Pre-Scrubber Solution: 40-45% (wt/vol) potassium hydroxide (KOH)
2. Post Scrubber Solution: 3% (wt/vol) silver nitrate (AgNO₃), acidified to pH 3
3. Acid: 2 to 4N Sulfuric Acid (H₂SO₄)
4. CM300-001 Carbon Cathode Solution
5. CM300-002 Carbon Anode Solution
6. CM300-003 Potassium Iodide (KI)
7. CM300-026 Sulfur Anode Solution
8. CM300-027 Sulfur Cathode Solution
9. External Carrier Gas (optional) (Note: An external carrier gas, such as nitrogen, helium, or CO₂-free air may be used in place of the internal air source of the Acidification Module if desired.)

PROCEDURE

ASSEMBLY

Assemble the Acidification Module and C/S Coulometer as instructed in their respective manuals. It is especially important to ensure that the special sulfur analyzer cell is leak free and that the flow from the acidification module always passes through the sulfur cell first. The cell solution on the carbon analyzer side of the instrument is adversely affected by sulfur compounds and passing the carrier gas through the sulfur analyzer first effectively removes all interfering compounds.

An optional solid silver or silver nitrate scrubber should be used in line between the sulfur coulometer and the carbon coulometer as an indicator of sulfur cell efficiency. Black precipitate in the silver nitrate solution or graying of the solid silver indicates that SO2 or H2S is not being properly absorbed into the sulfur cell solution.

Place a stir bar in a 100 ml sample flask and attach the flask to the bottom of the condenser on the Acidification Module. Secure the flask with the red locking ring. Place the flask and assembly into the heating and stirring port of the Acidification Module. Heating is not normally required so the condenser does not need to be connected to a cooling source. If an external carrier gas is used, adjust the pressure of the system to 2-5 psi. Set the flow to 100 ml/min. using the flow meter on the front of the Acidification Module. (See FIGURE 2 for an example of the set-up and flow diagram.)

ANALYSIS

Determine the background rate of the system by first analyzing a Blank sample. The instrument will use the saved blank value in calculating the final result values of subsequent analyses.

To perform an analysis, draw the sample into a syringe that is fitted with an injection needle. (See note on sample integrity.) Usually 200 to 300 l of sample is used depending on the samples H2S content*. Start the coulometer and inject the sample into the sample flask through the septum at the top of the sample column adapter. Add 5 to 10 ml of acid to flush the sample through the sample column line. The analysis endpoint will be automatically determined by the coulometer according to the user selectable settings saved within the instrument. All analysis data and parameters are saved to an SD Card. Data may also be printed to an optional printer or output to an external computer or LIMS.

*Note:Due to lower H2S solubility in the sulfur cell solution sample sizes should be adjusted to allow no more than 2500g S per sample at a 100ml/minute flow rate.

The weight of the sample can be determined in either of two ways. First, the syringe can be weighed before and after injection. The weight of the sample is determined by the difference between these two measurements. Second, if the density of the sample is known, the injection volume can be noted and the weight can be calculated. This method requires a volumetric syringe.

After a few samples are analyzed, the blank should be re-established and occasionally checked throughout the day. The sample flask does not need to be emptied until it is almost full.

Although calibration is not required, the instruments performance can be checked using calcium carbonate (CaCO₃) and Sodium Sulfite (Na₂SO₃). This is done by weighing 10 to 15 mg of CaCO₃and 5 to 10mg of Na₂SO₃into a small Teflon cup and placing it in a 10 ml sample flask. The sample flask is connected to the bottom of the condenser, purged, and then acidified. Alternatively, the user may use a liquid standard to verify the instruments performance. To prepare a 10, 000 mg C-S/L solution, weigh 3.237 g of sodium bicarbonate, 4.428 g of sodium carbonate and 3.931 g of sodium sulfite and transfer all to the same 100 ml volumetric flask. Bring to volume with reagent water. This solution should yield 2000g C and 2000g S when using a 200ul injection. The user should establish acceptance criteria for whichever type of performance check is used

NOTE: Sample Integrity Because of the ability of amine solutions to absorb CO2 or release H2S, sample handling is extremely important. The collection should be done so that the sample has as little contact with the air as possible. Ideally, the samples should be collected into bottles with septum tops. The septum top allows the sample to be drawn into the injection syringe without opening the sample bottle.

The Model 833 Vapor Pressure Osmometeris an effective, easy to use tool for the determination of number average molecular weights of any non-volatile solute in the range of 100-25, 000 Dalton.

Principles of Operation

The vapor pressure osmometer operates on the principle of differential vapor pressure between a pure solvent and a solution. Two carefully matched thermistors are placed in a chamber saturated with solvent vapor. When solvent is placed on both thermistors, they assume the same temperature. If a solution is placed on one of the thermistors, condensation heats the thermistor until the vapor pressure is raised to that of the pure solvent. The change in temperature causes a resistance change in the thermistor. This change in resistance is measured by a sensitive bridge circuit and displayed on a panel meter, strip chart recorder and/or computer terminal. A calibration curve relates the change in resistance to the molal concentration of the solution

The Model 833 VPO incorporates many improvements over other designs to simplify and improve molecular weight determinations. The cell and thermistor geometry are designed to minimize dilution of the sample by solvent condensation. This results in much slower fall-off and allows a much longer time window for readings. The syringes on the Model 833 are mechanically driven to insure more precise fluid delivery and are independently heated to minimize any equilibrium upset when introducing sample. This results in a faster equilibration time (typically 2-5 minutes), better reproducibility and greatly reduced cycle time per sample.

Applications include:Total sulfites in foods, dissolved SO₂and H₂S in amine scrubbing solutions, and sulfites in geological materials and wallboard.

The CM440 Total Sulfite, SO₂/H₂S Analyzeris a complete analytical system allowing the direct measurement of total sulfites or dissolved SO₂/H₂S in a wide variety of sample matrices and concentrations. Combining a automated, self-contained unit for the acidification of a sample (to evolve SO₂and/or H₂S), with a highly sensitive SO₂/H₂S detector, the CM440 easily handles solid or liquid samples with concentrations from ppm levels to 100% without user calibration. UICs analyzers are rugged, accurate and adaptable to most applications. They are used extensively in industrial, research and educational laboratories worldwide. The CM440 system includes the following components pictured above:

CM5014S SO2 Analyzer

• No user calibration
• Wide, linear dynamic range
• Readability to 0.01 g Sulfur
• User selectable display units
• Floppy disk drive for archiving data

Instrument Capabilities

A major advantage of the CM440 Total Sulfite, SO₂/H₂S Analyzer is the use of coulometric detection. Employing the principles of Faradays Law, the CM5014S SO₂/H₂S Analyzer automatically measures the absolute mass amount of sulfur dioxide and/or hydrogen sulfide evolved from an acidified sample. No user-calibration is required and linear detection is available from less than 1 g sulfur to over 10, 000 g sulfur. Using this 100% efficient coulometric process, relative standard deviations of 0.2% or better are common for standard material. For smaller concentrations, an absolute deviation of approximately 1 g S is typical.

complete analytical system allowing the direct, simultaneous measurement of TIC and sulfites in a wide variety of sample matrices and concentrations. Combining a self-contained unit for the acidification of a sample (to evolve CO₂, SO₂and H₂S), with a highly sensitive CO₂detector and SO₂/H₂S detector, theCM540 easily handles solid or liquid samples with concentrations from ppm levels to 100% without user calibration. UICs analyzers are rugged, accurate and adaptable to most applications. They are used extensively in industrial, research and educational laboratories worldwide. The CM540 system includes the following components pictured above:

CM5014 CO2 Analyzer and CM5014S SO2/H2S Analyzer

• No user calibration
• Wide, linear dynamic range
• User selectable display units
• Floppy disk drive for archiving data

Instrument Capabilities

A major advantage of the CM540 Simultaneous Carbon/Sulfur Analyzer is the use of coulometric detection. Employing the principles of Faradays Law, the CM5014 CO₂and CM5014S analyzers automatically measures the absolute mass amount of carbon dioxide, sulfur dioxide and hydrogen sulfide resulting from sample acidification. No user-calibration is required and linear detection is available from less than 1 g C/S to over 10, 000 g C/S. Using this 100% efficient coulometric process, relative standard deviations of 0.2% or better are common for standard material. For smaller concentrations, an absolute deviation of approximately 1 g C/S is typical.

Additionally, it is possible to analyze either solid or liquid samples. Sample flasks are available in 10, 25, 50 and 100 ml sizes. Solids or liquids may be weighed directly into the sample flasks. Alternatively, liquid samples may be syringe injected through a septum.

Oxidation times vary with sample type and temperature although 5 to 7 minute analyses are typical. To quicken CO₂and SO₂/H₂S evolution, sample heating and stirring capabilities are included within the CM5130 Acidification Module. Other features include the ability to: select different acids; add wetting/emulsifying agents; and, modify the flow path and scrubbers to optimize a particular application.

The CM320 Total Sulfur Analyzeris a complete analytical system allowing the direct measurement of total sulfur in a wide variety of sample matrices and concentrations. The CM320 consists of a dual zone, high temperature furnace and a sulfur coulometer. The CM320 easily handles solid or liquid samples with concentrations from ppm levels to 100% without user calibration. UICs analyzers are rugged, accurate and adaptable to most applications. They are used extensively in industrial, research and educational laboratories worldwide. TheCM320 system includes the following components pictured above:

CM5017S SO2 Analyzer

• No user calibration
• Wide, linear dynamic range
• User selectable display units
• Floppy disk drive for archiving data

CM5380 Dual Zone Furnace with CM5382 Sample Introduction Kit Programmable up to 1100OC Separate catalyst zone Automated oxygen dosing Split-tube furnace design for easy maintenance Instrument Capabilities A major advantage of the CM320 Total Sulfur Analyzer is the use of coulometric detection. Employing the principles of Faradays Law, the CM5017S SO2/H2S Analyzer automatically measures the absolute mass amount of sulfur dioxide and/or hydrogen sulfide evolved from a combusted sample. No user-calibration is required and linear detection is available from less than 1 g sulfur to over 10, 000 g sulfur. Using this 100% efficient coulometric process, relative standard deviations of 0.2% or better are common for standard reference materials. For smaller concentrations, an absolute deviation of approximately 1 g S is typical.

complete analytical system capable of measuring total sulfur and total sulfites in solid and liquid samples. Combining a dual zone, high-temperature furnace, a self-contained acidification module and a highly sensitive SO₂/H₂S detector, the CM350 offers the flexibility to analyze most any sample type and concentration with a precision un-matched by other analytical techniques. The CM350 system includes the following 3 components pictured above:

CM5014S SO2 Analyzer

• No user calibration
• Wide, linear dynamic range
• Readability to 0.01 g Sulfur
• User selectable display units
• Floppy disk drive for archiving data

CM5380 Dual Zone Furnace with CM5382 Sample Introduction Kit

• Programmable up to 1100OC
• Separate catalyst zone
• Automated oxygen dosing
• Split-tube furnace design for easy maintenance

CM5130 Acidification Module

• 10, 25, 50 or 100 ml reaction vessels
• Selectable volume acid dispenser
• Internal air pump with flow controller
• Controlled sample heating and stirring

Instrument Capabilities

A major advantage of the CM350 Total Sulfur / Total Sulfites Analyzer is the use of coulometric detection. Employing the principles of Faradays Law, the CM5014S SO2/H2S Analyzer automatically measures the absolute mass amount of sulfur dioxide and/or hydrogen sulfide evolved from a combusted sample. No user-calibration is required and linear detection is available from less than 1 g sulfur to over 10, 000 g sulfur. Using this 100% efficient coulometric process, relative standard deviations of 0.2% or better are common for standard reference materials. For smaller concentrations, an absolute deviation of approximately 1 g S is typical.

Sample sizes can range from 0.5mg to 10 grams with concentrations from 1ppm to 100%. Analysis times of 5-7 minutes are typical

TheCM5390Sis used in conjunction with UICs CM5120 or CM5300 high-temperature furnaces and either the CM5011, CM5012, CM5014 or CM5017 coulometer to provide an improved method of sample introduction.

TheAutomated Boat Inlethas a large, easy to access sample entry box, user selectable sample entry speeds, variable purge time setting and an integrated flowmeter. The CM5390S replaces the traditional dog houses and breech block assemblies found on UICs standard analytical systems.

EASY TO USE

The CM5390S eliminates the need to remove and replace breech block caps to insert and retrieve sample ladles. This also eliminates the chance of breaking any sample ladles.

Simply weigh out your sample, place it into the sample entry box, close and latch the lid, and start the analysis. The system is automatically purged of atmospheric CO2, the sample is then automatically introduced, analyzed and retracted* with no user input. Samples can now be analyzed with, literally, one hand tied behind your back.

*When used with a CM5014 or CM5017 coulometer

Carbon Analyzer is a complete analytical system capable of measuring total carbon, total organic carbon and total inorganic carbon in solid andor liquid samples. Combining a high-temperature combustion furnace, self-contained acidification module and a highly sensitive CO2 detector, the CM150 offers the flexibility to analyze most any sample type and concentration with a precision un-matched by other analytical techniques.

In order to align the height of the combustion tube and the breech block, ceramic tube insulation (CM162-016) must be placed around the tube at the furnace ends. It is important to note that each furnace requires a slightly different amount of insulation to align the tube with the breech block. The proper amount of bedding is the amount of insulation necessary to align the combustion tube without applying strain on the tube when mounted in the breech block and the furnace top is closed.Build up the combustion tube bedding from the bottom until the combustion tube is slightly above the breech block opening with the breech block in its lowest position. Periodically check the tube bedding is not built up excessively by gently closing the furnace top.Loosen the pedestal base thumbscrew and tighten the pedestal base onto the rail by turning the base clockwise.

This procedure is typically utilized for the analysis of amine solutions that are used to remove environmentally controlled emissions from flue gases. This method measures the amount of carbon dioxide (CO₂) and the amount of hydrogen sulfide (H₂S) in the scrubbing solution. This result is used along with other analyses to determine the amine scrubbing solutions efficiency and remaining capacity. This procedure may also be used for the analysis of sour water.

The system is composed of the CM5330 Acidification Module and the CM5016 C/S Coulometer. The Acidification Module is purged of atmospheric CO₂, SO₂and H₂S with an inert carrier gas. After purging the system, an aliquot of the amine solution is injected into the sample flask. Acid is then added using the dispenser on the Acidification Module. The gases evolved from the acidification of the sample then pass into the special cell on the Sulfur analysis side of the coulometer where SO₂and H₂S are absorbed into the solution and titrated.

CO₂is not absorbed into the sulfur detector solution and provides no interference. The CO₂enriched carrier gas is then routed to the cell on the Carbon analysis side of the instrument where it is absorbed and automatically titrated.

APPARATUS

CM5016 C/S CoulometerCM5330 Acidification ModuleSpecial, air-tight sulfur cellCarbon cell

REAGENTS

1. Pre-Scrubber Solution: 40-45% (wt/vol) potassium hydroxide (KOH)
2. Post Scrubber Solution: 3% (wt/vol) silver nitrate (AgNO₃), acidified to pH 3
3. Acid: 2 to 4N Sulfuric Acid (H₂SO₄)
4. CM300-001 Carbon Cathode Solution
5. CM300-002 Carbon Anode Solution
6. CM300-003 Potassium Iodide (KI)
7. CM300-026 Sulfur Anode Solution
8. CM300-027 Sulfur Cathode Solution
9. External Carrier Gas (optional) (Note: An external carrier gas, such as nitrogen, helium, or CO₂-free air may be used in place of the internal air source of the Acidification Module if desired.)

PROCEDURE

ASSEMBLY

Assemble the Acidification Module and C/S Coulometer as instructed in their respective manuals. It is especially important to ensure that the special sulfur analyzer cell is leak free and that the flow from the acidification module always passes through the sulfur cell first. The cell solution on the carbon analyzer side of the instrument is adversely affected by sulfur compounds and passing the carrier gas through the sulfur analyzer first effectively removes all interfering compounds.

An optional solid silver or silver nitrate scrubber should be used in line between the sulfur coulometer and the carbon coulometer as an indicator of sulfur cell efficiency. Black precipitate in the silver nitrate solution or graying of the solid silver indicates that SO2 or H2S is not being properly absorbed into the sulfur cell solution.

Place a stir bar in a 100 ml sample flask and attach the flask to the bottom of the condenser on the Acidification Module. Secure the flask with the red locking ring. Place the flask and assembly into the heating and stirring port of the Acidification Module. Heating is not normally required so the condenser does not need to be connected to a cooling source. If an external carrier gas is used, adjust the pressure of the system to 2-5 psi. Set the flow to 100 ml/min. using the flow meter on the front of the Acidification Module. (See FIGURE 2 for an example of the set-up and flow diagram.)

ANALYSIS

Determine the background rate of the system by first analyzing a Blank sample. The instrument will use the saved blank value in calculating the final result values of subsequent analyses.

To perform an analysis, draw the sample into a syringe that is fitted with an injection needle. (See note on sample integrity.) Usually 200 to 300 l of sample is used depending on the samples H2S content*. Start the coulometer and inject the sample into the sample flask through the septum at the top of the sample column adapter. Add 5 to 10 ml of acid to flush the sample through the sample column line. The analysis endpoint will be automatically determined by the coulometer according to the user selectable settings saved within the instrument. All analysis data and parameters are saved to an SD Card. Data may also be printed to an optional printer or output to an external computer or LIMS.

*Note:Due to lower H2S solubility in the sulfur cell solution sample sizes should be adjusted to allow no more than 2500g S per sample at a 100ml/minute flow rate.

The weight of the sample can be determined in either of two ways. First, the syringe can be weighed before and after injection. The weight of the sample is determined by the difference between these two measurements. Second, if the density of the sample is known, the injection volume can be noted and the weight can be calculated. This method requires a volumetric syringe.

After a few samples are analyzed, the blank should be re-established and occasionally checked throughout the day. The sample flask does not need to be emptied until it is almost full.

Although calibration is not required, the instruments performance can be checked using calcium carbonate (CaCO₃) and Sodium Sulfite (Na₂SO₃). This is done by weighing 10 to 15 mg of CaCO₃and 5 to 10mg of Na₂SO₃into a small Teflon cup and placing it in a 10 ml sample flask. The sample flask is connected to the bottom of the condenser, purged, and then acidified. Alternatively, the user may use a liquid standard to verify the instruments performance. To prepare a 10, 000 mg C-S/L solution, weigh 3.237 g of sodium bicarbonate, 4.428 g of sodium carbonate and 3.931 g of sodium sulfite and transfer all to the same 100 ml volumetric flask. Bring to volume with reagent water. This solution should yield 2000g C and 2000g S when using a 200ul injection. The user should establish acceptance criteria for whichever type of performance check is used

NOTE: Sample Integrity Because of the ability of amine solutions to absorb CO2 or release H2S, sample handling is extremely important. The collection should be done so that the sample has as little contact with the air as possible. Ideally, the samples should be collected into bottles with septum tops. The septum top allows the sample to be drawn into the injection syringe without opening the sample bottle.

The Model 833 Vapor Pressure Osmometeris an effective, easy to use tool for the determination of number average molecular weights of any non-volatile solute in the range of 100-25, 000 Dalton.

Principles of Operation

The vapor pressure osmometer operates on the principle of differential vapor pressure between a pure solvent and a solution. Two carefully matched thermistors are placed in a chamber saturated with solvent vapor. When solvent is placed on both thermistors, they assume the same temperature. If a solution is placed on one of the thermistors, condensation heats the thermistor until the vapor pressure is raised to that of the pure solvent. The change in temperature causes a resistance change in the thermistor. This change in resistance is measured by a sensitive bridge circuit and displayed on a panel meter, strip chart recorder and/or computer terminal. A calibration curve relates the change in resistance to the molal concentration of the solution

The Model 833 VPO incorporates many improvements over other designs to simplify and improve molecular weight determinations. The cell and thermistor geometry are designed to minimize dilution of the sample by solvent condensation. This results in much slower fall-off and allows a much longer time window for readings. The syringes on the Model 833 are mechanically driven to insure more precise fluid delivery and are independently heated to minimize any equilibrium upset when introducing sample. This results in a faster equilibration time (typically 2-5 minutes), better reproducibility and greatly reduced cycle time per sample.