Making Standards and Filling the Autosampler

Making Standards and Filling the Autosampler#

  1. It is now time to make the standards and fill the Autosampler. Choose the rack editor (funky dot filled rectangle between DB down arrow and the red “Stop”. Choose a “new file”, make sure it has 44 cups and save to RackFiles folder on C:/. You are very limited to what you can have as the title (Only 8 characters, no spaces, no special characters). Be sure to record what you use for your title in the book so both yourself and others will know how to find it.

  2. Sample ID’s are 10 characters. You can autofill (say all have same start, type that start, highlight samples with that start, touch autofill on the top bar of the screen. Or you can sequences, same rules except touch sequence on the top bar of the screen.

    Caution

    Be specific, no duplications since the last step will average numbers for any sample with the same name (does not matter if they were ran on different days or not)

  3. Samples go into one of the 44, 15 mL tubes — fill to a little over height of the rack; standards go into the 14 larger cups. This lab you will only be using the larger standard cups for the standards! (Unknowns are a different story)

  4. Making the standards: We prepare a series of 11 metal standards. There are labeled volumetric flasks for each standard as well as labeled tubes for each standard.

  5. The easiest approach is to make a large volume of 5% nitric acid and use it as the solvent in the flasks in place of distilled water. Basically, just add 50 mL of the 69-70% HNO3 to the 1000 mL V. Flask. Remember to have a little bit of DI water in the flask before you add the acid, then once the acid is added you are good to fill to mark.

    Danger

    USE GLOVES WHEN WORKING WITH CONCENTRATED NITRIC ACID (This is the highest concentration of nitric acid possible in aqueous solution… fyi)

    If you spill or splash some on yourself, immediately notify your instructor so that the spill kit can be obtained… in the meantime remove your gloves and rinse the area with copious amounts of water at the sink

    If you spill some on the counter, be sure to clean this up with the kit as well otherwise someone may unknowingly place their elbows, hands, laptop, notebook etc. on the counter and begin to wonder why their skin is burning…

  6. First let’s prepare the 10 ppm standard. Screw up this one, and it’s all over … Add three 833 μL aliquots of the purchased stock (PlasmaCAL custom multielement standard – don’t screw it up! This was $300 for a bottle) to the 250 mL volumetric and dilute to the mark with the appropriate solvent (5% HNO3, the one that you prepared in the 1L bottle). Invert to ensure proper dilution

  7. Follow the standard prep using the table below

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  8. After filling all standards with appropriate solvent to the line, invert and mix 15 times. Fill all the standard tubes (The large ones in the rack by the instrument! 2.5 cm diameter) and place in the Autosampler rack in their appropriate positions. They should already be in their correct spot and if they aren’t… well good luck

  9. To prepare the 10 ppm Mn/Fe standard, add 1 mL 1000 ppm Mn and/or Fe. Fill with 5% nitric to the line. Invert, and mix. Fill the standard tube and place in Autosampler rack cell location 14.