Hi Rachel! CRMs are an excellent way to measure the accuracy of your Workflow. I disagree with the previous poster on one thing, properly CRMs need to go through a Round Robin study that involves many labs to get statistics on what the "true" values are, so you can't just make your own CRMs. On your question, I would consider the availability of a CRMs for the particular matrix that the study covered. If it's available, I would request that the researchers would include in their procedure and thus evaluate the accuracy of their workflow. If not, then they should at least perform matrix spike experiments using a standard from a second manufacturer (other than the one used for calibration). Hope it helps, cheers from sunny Miami :)

Hi guys!

Well, the paper is dealing with fish samples, so we have lots of CRM available, mainly fish muscle and fish liver, commonly used in these analyses. Usually in ICP-MS we use BOTH external standards, such as mixtures of metals at different concentrations and plot an analytical curve, AND certified reference material, to guarantee that the methodology is accurate, since the CRM gives a value X that should be the same value with a certain SD found by your analysis. I've never seen ICP-MS papers that DIDN'T use CRM, but I do know they're expensive. I'm stil very much in doubt about accepting the paper... any more opinions out there?

Cheers!

(Cesar, it's unusually cold in Rio now, which I could be in Miami right now, I hate the cold, not a very good Brit! hehe)

Hello Rachel,

If there are CRMs available that are relevant to the sample types discussed in the submitted manuscript, then I would advise the authors to analyze one or more CRMs (that you could suggest) before accepting their paper for publication. This is a fair request. If the reference materials are prohibitively expensive for this group, then they could request a small amount from a colleague. That said, the cost of a CRM is small compared to the total cost of the research project.

Pete

Thank you for your input Pete, that´s what I thought. CRM are expensive, but you can always get a small amount from another lab or institution. I´ll request the authors to do this.

In fact, this is the second round of reviews, I already requested they insert the information, but as they didn´t, I don´t think they actually conducted the analyses.

Thanks again!

Cheers,

Rachel

Please, can anyone explain certified reference material (CRM) and its function? Thank you

Hello Oluwatobi, the CRM is used to guarantee precision in your analyses. They are a standard with known metal concentrations that you can use to guarantee your results. Example: The CRM has 1 mg/kg of zinc. When you digest and read the CRM just like you did the samples, you should obtain a value around 1 mg/kg of zinc, that value is known for many elements in the same sample and is given in the data sheet for the CRM. Ideally, the CRM should be as close as possible to your samples, such as when analyzing fish tissue, you can use fish CRM, when analyzing blood, use blood CRM, and so on. Of course, this is not always possible, but would be ideal. :)

Thank you Racheal

Hi Rachel Ann Hauser-Davis, I have to use CRM for Human serum and mice tissue samples like liver, spleen, intestine (duodenum). Can you please guide me where to get CRMs for these and how expensive are they, that will help a lot. Also, please suggest if someone can give a small amount.

Cheers!!

@Sandeep, I usually buy CRM from Sigma Aldrich/Merck, but I am in Brazil, and have no idea where you are and if you are able to obtain them from the same source. sorry, I can't help you concerning CRM donation. Best, Rachel

Thanks Rachel Ann Hauser-Davis. I am from India (New Delhi). I will look from Sigma. It will be helpful if you can share a link or catalog number.

Best.

Hello Rachel Ann Hauser-Davis. A journal reviewer has asked me for the CRM for my sample and I am not able to find it. While looking for the CRM i came to know that the CRM is only available for biota and hence it is not available for my sample.What can I do if the CRM is not available for a sample?

You should use a CRM as similar as possible to your sample, if there is none available as the same matrix. What are your samples?

@Rachel Ann Hauser-Davis. The samples are Microplastics.

Hmm Difficult. Either you use a micro plastics reference material, which I know isn’t available, or you simply use any other certified reference material and go with that. I would of course be sure to state that there isn’t any certified reference material for micro plastics available in your text. I

@Rachel Ann Hauser-Davis Thank you