Hello Edzani,

At my previous lab, we purchased individual single element standards and added the appropriate amounts to a 1L volumetric flask to have the concentration you require.

Most common are 1000 mg/L solutions, but to get 1000 mg/L as the final concentration, you'll need to use 10000 mg/ L solutions, which are available for the major cations you're after.

Adding 10mL of each 10000mg/L solution of the 4 single element solutions of Mg, Na, K and I assume Ca, to 100mL volumetric flask will give 1000 mg/L.

You'll have to calculate the nitric acid. For 5%, you'll need 5mL and the single element solutions will be in a nitric acid solution, commonly 3%. Therefore, in 10mL, you'll have added 0.3 mL, times 4 for the 4 element solutions and you would have added 1.2 mL.

Just add another 3.8mL of nitric acid to have 5% nitric acid.

This is one example with a few assumptions,so adjust your calculations accordingly.

I hope this helps.

Cheers,

Adam

ICP reference standards are usually made from high purity single element salts, so I would recommend finding a high purity nitric acid (low metal content) and use it to make a 5% Nitric acid sample diluent (100mL HNO3 into 2L volumetric flask containing 1200mL Grade 1 Analytical water & QS to volume with analytical water). Add oven dried 2.54 g NaCl to a 1L Volumetric flask containing ~600mL sample diluent, mix well, and QS to volume with sample diluent. Solution preparation works best if you dissolve all of the solids 1st, then QS to volume. Are you sure you want mg/mL and not ug/mL? Then for your other cations, 1.907 g KCl, dried at 110 °C for 1 hour before weighting; 2.497 g CaCO3, dried at 180 °C for 1 hour before weighting, & 1.658 g MgO to a 1000 ml volumetric flask. Once you have your individuals solutions then you can use the formula C1V1=C2V2 to make your combination solution using volumetric glassware. At this concentration level, the plasma will be predominantly orange due to Sodium.

I would recommend building single element curves 1st so you can develop an eye for recognizing elements in the plasma, the ability to gauge concentration in your plasma, and it can serve as a baseline to understanding how and when you will need to make interfering element corrections.

Adam Crawford thank you but the technician is refusing to buy the ready-made one hence I am asking for assistance.

Michael Sanford do I make let's say for example 1000 mg/L of Mg concentrated solution using DI water first before I add to the diluted 5%nitric acid?

My preferred way is make a 5% nitric acid solution and use it as a solvent for standard solution preparation. This way you only have to handle the acid once. You can pipet 50mL Nitric acid into your 1000mL volume metric flask, but you will be dealing the 1) exothermic reaction between acid-water, 2) restricted narrow gas exit, and 3) handling significantly warm glassware while mixing the two together. The former solution approach, you can grab a 2 liter reagent bottle, stir bar, stir plate, and a 2L graduate cylinder. Add 1400mL analytical grade water to the cylinder, add 100mL nitric acid, and QS to volume with analytical water. Pour the solution into 2L bottle with a funnel, and let it stir for 30 minutes.

Respested Adam Crawford,

I was reading your method and think it would work for my case. My concern is that while preparing a 100 ml of 1000 ppm solution, we add 3.8 ml of nitric acid and 10 ml of standard solution.

Therefore, volume of water added will be: 100-(3.8+10) = 87.2 ml.

Kindly, let me know if this is correct or not.

With regards,

Vishawjot

Vishawjot Sandhu the calculation you reference is for a single element Stand ard solution preparation. Adam's 3.8mL HNO3 addition was based on 4 element Standard solution preparation to achieve 5% HNO3 solution. If you are preparing a single element stand solution, you would need to use a different volume of HNO3 to achieve 5% HNO3 depending on the weight % of your concentrated HNO3. If you prepared the 4.7% HNO3 solution and used it as your solvent, then your single element preparation would be 5.0% HNO3 solution matrix. Technically, you will not see a significant change in your ICP signal if the HNO3 acid matrix is 5.0% or 5.3%.

Dear colleague,

You must prepare above mentioned multi-elemental standard solution by the following steps:

1.Preparation of mono-element standard solutions with concentration 10 000 µg/ ml for Mg, Na and K in 100 ml graduated plastic flask by dissolving the corresponding Nitrates (Suprapur, Merck) of above mention elements in nitic acid of highest purity grade (Suprapur, Merck) by using PTFE beakers.

10 000 mg/L = 10 000 µg/ ml

2. 10 ml from 10 000 µg/ ml of each of above mentioned mono-element standard solutions must be transferred to a 100 ml polypropylene graduated flask and was brought up to volume with 5 % nitric acid.

Final solution contains Mg, Na and K, each with concentration 1000 µg/ ml.

I will note the following:

- The above mention solution is with high concentration of Mg, Na and K, and cannot be used for determination of these elements by ICP-OES, because the prominent lines of elements are with high sensitivity in ICP-OES in accordance with Line Coincidence Table for Inductively Coupled Plasma Atomic Emission Spectrometry [1].In addition the concentration of Mg, Na, and K is high and this solution cannot be stable with the time.

- You must prepare mono-element standard solutions for Mg, Na and K by dissolving the corresponding Nitrates (Suprapur, Merck) of above mention elements in nitic acid of highest purity grade (Suprapur, Merck) by using PTFE beakers.

- I recommend to use the Merck Titrisols (Merck ICP-AES mono-element standard solutions) and to prepare the mono element standard solutions in 100 ml volume with concentration 1000 µg / ml for Mg, Na and K. From these mono element standard solutions you can obtain complex solution in lower concentration range (for example between 1 µg / ml and 10 µg / ml).This complex solution can be used for determination of above mentioned elements by ICP-OES.

Plastic or PTFE ware must use throughout; Reagents of highest purity grade; 65% HNO3Suprapur, Merck and tri-distilled water from a quartz apparatus. These conditions are necessary for elimination of possible contaminations for Mg, Na and K.

References

[1]. P.W.J.M. Boumans, Line Coincidence Table for Inductively

Coupled Plasma Atomic Emission Spectrometry, Pergamon,

Oxford, 1980, 1984.