RSH/H2S

Question 1

Preparing Samples

Answer 1

•Using lead acetate paper moistened with DI water, check vapor space of sample for presence of H2S. If H2S present, it should be quantified. If computer cannot quantify, record as

Question 2

Program Instrument

Answer 2

•Load Tiamo 2.4 software
•Click Workplace icon
•In Run window click on Single Determination tab
Under Sample data, pull down Method and select RSH/H2S. Enter sample name, specific gravity and sample size
•Click Manual icon on bottom left. click prepare and press Green start button. (this ensures no air in line).
•Click Workplace again, and hit start button.
•when titration complete, rinse electrode with DI water over 300 mL sample cup. Pour contents down sink with running water. Rinse cup and acetone/air dry.

Question 3

Data Analysis

Answer 3

• Click Database
• Right click sample and select Reprocess. If you need to modify a variable, for instance AgNO3 conc. or sample size, double click and change.
• Curve evaluation tab is very important and ONLY PLACE THAT SHOWS THE DERIVATIVE of the curve-if curve needs modified click Edit button
• To delete endpoints, select hand tool and right click EP and select delete
• To add endpoint, click cross hairs and click place where point goes
• Once editing is finished click OK and hit YES when window pops up.
• Click Recalculate to have changed take effect.

Question 4

Interpretation of Results

Answer 4

•Endpoint Ranges:
If more than 1 endpoint:
H2S range is approx. +100 to +300 mV
RSH range is approx. -300 to -200 mV

•If you have 3 or more endpoints:
Edit graph to 2 endpoints using appropriate ranges

•If no endpoints:
Report RSH as

Question 5

Calculations and Reporting Data

Answer 5

H2S = (mLs of H2S endpoint x 0.16)/(Specific gravity x Sample Size)

RSH = ((mLs of RSH endpoint - mLs of H2S endpoint) x 0.32)/(Specific gravity x Sample Size)

**Multiply each endpoint by 10000 or move decimal place four places to right to convert from wt% to ppm

Question 6

QC Standards

Answer 6

• Kerosene Side Stripper from Unicracker spiked with butyl mercaptan is analyzed daily as a QC Std. 20 mL sample size of standard reagent is analyzed and results in NWA to determine instrument performance.
• Std should be run with daylight batch of sampeles or within a short amount of time before. DON’T RUN STD BEFORE 04:00 HOURS.

Question 7

Purpose

Answer 7

Concentration of hydrogen sulfide and mercaptan sulfur in gas, kerosene, aviation turbine fuels and distillate fuels. Mercaptans have odor and adverse effect on fuel system O-rings and gaskets (elastomers)