for water samples, you can try infrared spectroscopymethod. It is a fast, inexpensive, and non-hazardous methods for nutrient concentration determination in water samples. See http://dx.doi.org/10.1016/j.scienta.2012.06.037 for detail.

Dear Shahid,

If you want to analyze separately then several methods are available, if you want to analyze them together its LCMS and GCMS as per compound type. I can provide you both and you can also find yourself it’s not very difficult task.

Regards

Amir

Microwave digestion for soil and plant samples followed by ICP-OES. For water saples you can filter through 0.45 micron filter and acidifying , followed by ICP-OES

Hello Every one,

I am working on Human Physiology.

Can you have any idea about analysis of micro nutrient in Human sample?

We are not doing analysis of trace elements in human routinely ?

Thank you.

Inductively coupled plasma. Use liquid argon and liquid nitrogen if you have access to them to keep the costs down. You will need to digest or extract the soil or plant samples before analysis by ICP. You may be able to use lasar ablation with ICP to analyze soil and plant samples in the powder form, so that you won't have to prep them with acid digestion or extractions beforehand. You may want to check out XRF, which can analyze an intact sample, however the results can be quite variable in some instances.

Dear Thomas we are looking for both elemental and molecular

Am already determined most of elements in soil samples , could you please give small ref or critical level values of the most elements such as (trace , harvey ..etc)

Dear dr shahid,

hi

I have used acid digestion and i took good result. indeed, i accep by mr. Carlos Garcia-Delgado that Soltanpour and Schwab( 1977) method is good method for exterction both salt and plant.

Dear Ahmed

Attached you will find a review article on micronutrients in the argentine Pampas's soils. This article shows critical levels used worldwide.

Regards, Martin

Usind Atomic Absorption Specroscopy should be enough to fulfill your objective.

For Plant sample you have to digest them prior to analysis. This can be done either

as acid wet digestion or as dry digestion by ash drying the samples.

Well, all the above suggestions are based on destructive analysis of samples. And as I understand your question, you mean determination without digestion. If that is the case, then you need to employ XRF which is non-destructive method that determines elemental samples directly from un-digested samples.

For soil, plant, and water samples XRF is good for elements at concentrations of ppm and above. For trace elements you will need to digest your samples and run via atomic spectroscopy.

Simply acid digest the samples after drying and finely grounded on hot plate/oven. and which acid is convenient you can go for APHA. As far as instrument is concerned Atomic Absorption Spectrophotometer / ICP-AES are recommended. Both give good results conveniently.

In terms of timer, ICP would be the best option. However, costwise it would be very high. Also you could do the same analysis with AAS, but analytical time would be more. And still if you can not afford to do the ICP or AAS, you can do it spectrophotometricall, but specifically for each element you require specific chemicals, but will genberally be less expensive.

The water soil and plant meterial need to be digested using suitable acids in order to bring the nutrients to the solution which can be used to feed to ICP or AAS.

Also in soil if you require only the plant available form you can extract the soil with DTPA (if the soil is alkaline) or with 0.1 N HCl (if the soil is acidic)

AAS (Atomic Absorption Specroscopy) is the best instrument to analyse nutrients in any matrix. However, if you are also aiming at speciation then you may also use UV-Vis. While ICP-MS is expenses, it is the most accurate instruments for element analyses.

The question is another. The question is: what much more money do you have for...?

After your response..., I can give you a correct response.

Best regards:

For the determination of nutrients in soil and plants, both will require acid digestion. Where the nutrients are in very low concentration like in water, you would require a very sensitive instrument like the ICP OES or ICP MS which has very low detection limits to be able to pick such elements. X-Ray Fluorescence (XRF) can be used for element determination directly in soils, but its sensitivity is lower. So your choice of instrument will depend on purpose and how much money you have to put in.

@Uriah, Are you letting us understand that detection limits of metals for X-Ray Fluorescence is higher than ICP OES or ICP MS. That means X-Ray fluorescence can only be applied when level of metals is already known to be very high.

@Clement Ogunkunle, Detection limit is w.r.t. the ability of the instrument to detect the metals. Detection limit relates to the minimum concentration present in a certain matrix which an instrument can analyse. Thus, the higher the detection limit, the higher is the instruments accuracy. Here higher detection limit is w.r.t. to the lower concentration of metal. Thus, if the detection limit is higher then even much lower concentrations of metal can be detected by the instrument.

Mr Clement Ogunkunle, The comments by Rachna Chandra adresses the issue. I hope you are satisfied by this.

Thank you Uriah Lar and Rachna Chandra for the beautiful contributions and clarification.

actually, there are some factors that should be considered. Its depends on the types of samples, what types of elements to be determined, the cost of analysis, the availability of the instruments etc. ICP-MS could be considered the best to be used with high accuracy and able to give reliable results. It also happen to EDXRF which is considered as good as others. by applying EDXRF, the results still can be considered as reliable and the most important advantages of this technique is due to simple sample preparation dan no wet digestion technique need to be applied on.

it depend on the availability of instruments and budget. i think AAS is best method. icap-aes can also be used based on budget

In terms of time, ICP of course. Waters can be directly introduce in the ICP, plants after acid digestion, and soil after DTPA o similar extraction

Except for water samples, you always have to extract soil and plant tisseu to be analyzed. I will suggest, if you have some money an ICP-OE, is not as ICP-MS but is still an incredible accurate instrument.

I think AAS is better optional because this instrument is available in most of the labs.

In term of time, the most convenient equipment is ICP-OES, and if you don’t have budget limitations, I would acquire ICP-MS, that allow you to extend the analysis in your matrices (water, foliar and soils) to isotope determinations

for water samples, you can try infrared spectroscopymethod. It is a fast, inexpensive, and non-hazardous methods for nutrient concentration determination in water samples. See http://dx.doi.org/10.1016/j.scienta.2012.06.037 for detail.

The depends on the trace element concentration and the matrices of the samples (water coul ususlly be measured directely or after filtration: solid samples (soil, plants, sediments...) needed a previous digestion). In this way you can use an AAS (higer concentrtion); ICP-OE or an IC-MS (traze and ultratrace elements)

for quicker results ICP can be used while for quality and accurate results AAS is an option

Soils can be analysed with XRF without wet digestion. You can even get portable XRFs so instant measurements can be taken on soils in the field. I would however recommend digestion and spectroscopic analysis if possible to obtain reliable reproducible total concentrations.

XRF is very useful in field campaing ir order to optimize soil sampling and, in for some heavy metals is a good and quick way to estimate their content in the soil sample. Nevertheles, the LOD / DL for some elements is too high or no adecquate one, giving only a poor estimation, therefore, being necessary their analysis at the lab (ICP, AA,....)

the most convenient "instrument" for micronutirent soil determination needs

1/ to integrate the precision of the method that is use to extract the micronutirent from the soil depending :

2/ if the determination will concern total nutrients forms and/or just plants available or soluble nutrients depending

3/ if you want to measure the micronutrients just one or two times per year or if you want to analyse the nutrient flow in real time for one or several months or a year.

Indeed, if the nutrient analyses are in correlation with plant nutrition, we have experience that all the chemical methods issued from soil sampling are less effective than the Plant Root Simulated PRS probe system (cationic and anionic membranes) which allow to extract quickly simultaneously 14 nutrients then analyzed them by ICP-OES.

To analyse total nutrients forms, the best way is also ICP-OES and need chemical or microwave approach extraction procedures

The best instrument in terms of quality and time to quantify micronutrients in soil, plant water is AAS

Anybody have done micrinutrient analysis with icp oes?. If so kindly send the sop or please give some information related to ammonium acetate extraction( K Ca Mg Na).

Hello All, very interesting answers. I have a rather clumsy situation. I prepared for AAS and arranged for set up and chemicals of extraction accordingly. However because of some practical issues, I have to use ICP. Now I am not sure if I can use the same extraction procedure and analyse the extractant using ICP. The objective is to analysis Plant available nutrients. The methods I am prepared for are as follows,

1) CEC by Sodium Exchange method

2) Available P: Bray's or Olsen's depending on pH

3) Avl. K: Ammonium acetate extractant

4) Avl. S: Barium sulphate precipitation method

5) Zn, Fe, Mn, Cu: DTPA extraction

6) Avl. B: sample boiled with activated charcoal and filtered

7) Avl. Mo: Ammonium acetate

The reason for abiding to these methods is because I do not have my own coorelation studies and I am relying on fertilizer recommendations given by public labs in Maharashtra, India. The methods of analysis are as per their manual.

Thank you!

1) If you are using sodium acetate as the saturating solution, you will most likely use an ethyl alcohol rinse after the saturating step and then use ammonium acetate (we use 0.5N MgCl2) as the exchanging step. If you use alcohol  to flush out residual sodium, then you will need to dilute the samples 1:10 to run them on the ICP, since alcohol will blow out the plasma. You can adjust the ICP conditions to run organic solvents, however it is easier to just dilute the solution and run it on the ICP. Be sure to include your dilution factors for the final results.

2) you can run Bray or Olsen's extracts by ICP, however a small torch tip may clog due to the high dissolved solids in the solution. If possible, use a torch tip of about 1.5 mm to avoid clogging. The Perkin-Elmer ICP's generally use larger torch tips that can handle samples with higher total dissolved solids. The older Jarrell-Ash or Thermo ICP's may use smaller glass torch tips that can clog or decompose when they are exposed to salty solutions. The newer machines may have larger torch tip openings. Check out the following reference for using Olsen's method with DTPA with the ICP: Rodriguez, J.B., J.R. Self, G.A. Peterson, and D.G. Westfall. 1999. Sodium bicarbonate-DTPA for macro- and micronutrient elements in soils. Communications In Soil Science and Plant Analysis 30 (7&8): 957-970.

3 and 7) You can easily run ammonium acetate (1N, pH7.0) extracts for K and Mo by ICP. The extracts settle out quite well and also filter easily to obtain a clear solution.

4) Most newer ICP's used purged systems that allow for the analysis of sulfur. The barium chloride method is actually a means of precipitating sulfate as barium sulfate and then measuring the turbidity of the solution or determining the final dry weight of the barium sulfate precipitate. A method that can be used by ICP is to extract with calcium phosphate monohydrate (Ca(H2PO4)2-H2O) that contains 500 ppm P (2.02g Ca(H2PO4)2-H2O per liter of water), 0.1M LiCl, or 0.15% CaCl2. The method is in Methods of Soil Analysis Part 2-Chemical Methods, American Society of Agronomy.

5) Micronutrient extractions using DTPA are easily analyzed using ICP.

6) Hot water extractions for boron can be easily analyzed by ICP. Just make sure you filter out the charcoal.

Note: Be sure your extracts are filtered and free of any suspended particles. Also be sure to make up standards for each test in the solution that is used for the extractions. In some cases you may have to dilute the samples if the analyses exceed the analytical range of the instrument. The advantage of ICP is that the standard curve can be extended by several orders of magnitude beyond your high standard.

Jim Self

Colorado State University

Soil, Water, and Plant Testing Lab

Dear Jim,

Sir, Thank you for such an elaborate and exact reply with practical tips. This is one of the best answers I have read on researchgate.

Thanks, Rohan

Hi, I have gone through all the answers and have two follow-up questions. First, is there any difference in maintenance costs between ICP-MS and ICP-OES. The second question is if there is any issue to use ICP-MS for nutrients analysis in soil, plant tissues, and water relative to ICP-OES use?

Thanks,

Bhupinder

1. Yes, there is a difference in maintenance costs between ICP-MS and ICP-OES. ICP-MS can be much more expensive to maintain than ICP-OES. Roughing pumps for the ICP-MS, for example, can run about $25K (US). Service visits can be $5K (US). I strongly advise anybody getting an ICP-MS to get a service contract. They can be expensive, but you may find that you will save money in the long run, especially if the machine starts getting older. I have a Perkin Elmer DRCII that I got when it was about 3 years old. I got the service contract for $17K/year. In the first year, I had to get a roughing pump replaced as well as needing to have it adjusted since it was burning holes in the induction coil. Having the service contract actually saved me money . There are things that you can do yourself such as replace the torch or lens, and replace the pump oil. The newer machines, however may be much more reliable and manufacturers are always thinking of ways to cut down on maintenance and argon usage. The ICP's that I have had rarely needed much maintenance from outside service calls. I have had Jarrell-Ash, Thermo and Perkin Elmer machines. Most of the time I was able to service them myself. The only times I needed to call a service rep was when a power tube had to be replaced. I have never had to have a service contract for an ICP-OES, however, it may not be a bad idea to have one, once the warranty expires.

2. I typically run soil nutrient analysis that are usually in ammonium bicarbonate-DTPA, ammonium acetate, Mehlich III reagent, etc by ICP-OES. I usually run soil/plant digests and water by ICP-MS. I am not sure how the ICP-MS would handle extractants that are high in salts. I don't think it would be a major problem, however the cones in ICP-MS could get fouled with salt deposits.

Hi Jim, You detailed feedback shows that you have great amount of experience about lab instruments and procedures. I am glad that you had time to respond back to my query. I will now stick with ICP-OES choice. Another follow-up question, i may not be able to buy nitrogen analyzer but is there any method I can use to measure plant tissue nitrogen concentration without spending much money? Thanks, Bhupinder