DA User Info

1. Staff Contact:  Doug Turner (650-678-6454)

2. General: The WestCo SmartChem 200 discrete analyzer is available to all members of the Stanford community.  This is a user run instrument.  Before signing up, users must complete a training session on the instrument and be certified by a facility technician. Once certified, users planning to run samples must sign up on the DA Scheduler.  In addition, all users must fill out the log book each time the machine is operated.  Users should also reference the SmartChem 200 Basic Startup Procedure for assistance and ask Doug when questions arise. Safety glasses are mandatory while operating this instrument. 

3. Operation:  The discrete analyzer is available for use Monday - Friday, 8am to 5pm.  Experienced users can make arrangements to use the instrument during off hours.

4. Cost:  The discrete analyzer costs $20 per hour.  Please note that the charged time includes instrument setup, standard preparation, and data finalization.  The user is responsible for accurately reporting start and end times in the log book.   Users must have a valid Stanford PTA to sign up for this instrument.

5. Samples: All samples for analysis must be in aqueous form.  Unknown samples must be free of solid particulates.  Water samples should be filtered with a 0.45mm or smaller membrane filters, while 2N potassium chloride extractions should pass through Whatman #1 filter paper.  Filtered samples need to be poured into plastic cups provided by the facility and placed in the sample rack.  Solids in the samples can cause inaccurate readings and clog the sample probe, resulting in expensive repairs, replacements, and down time on discrete analyzer which we would like to avoid.

6. Standard Solutions: The lab provides standard stock solutions of nitrate, nitrite, ammonium and phosphorus, as well as volumetric flasks dedicated to various concentrations and matrix solutions.  Users are expected to make the appropriate high standard for their method from these stocks.  The instrument will make the other necessary standards from the single high standard that the user provides.  The standard solution should be prepared by the users in the same matrix as the unknown samples.  Prepare your standard carefully because it will affect the accuracy of your results. 

7. Rate of Analysis: 

   • Nitrate - 1st Hour: 15 samples (with wash, wbl, standards and rbl).  Each subsequent hour: 40 samples

   • Nitrite - 1st Hour: 20 samples (with wash, wbl, standards and rbl).  Each subsequent hour: 45 samples

   • Ammonium - 1st Hour: 20 samples (with wash, wbl, standards and rbl).  Each subsequent hour: 45 samples

    

8. Detection Limits: 

   • Nitrate-N - 0.04 - 5.0 mg/L N

   • Nitrite-N - 0.02 - 2.0 mg/L N

   • Ammonium-N - 0.05 - 5.0 mg/L N

   • Phosphate-P - 0.03 - 3.0 mg/L P

    

9. Ordering Information:   EM1 will supply sample cups, standard solutions and reagents.  If you will be doing routine analysis and/or would like to prepare the samples in your lab, you can purchase the 4mL sample cups through E&K Scientific, part number 550400.  Caps are part number 450000.

Data: After analysis is complete, please remove your Excel files from the instrument computer via memory stick or email.  All raw data collected on the DA computer will be saved for at least 30 days.

You can get more detailed information by checking out our FAQ.