About the analytes

Dithiocarbamates

Dithiocarbamates are compounds analoge of the carbamate group with the exception that the oxygen has been susbtituted by a sulfur atom, there are two types: mono and bisalkyl-dithiocarbamates d1. they are pesticides organophosphorated mainly used as fungicides and in some cases as mammal repelent d2, they are non-systemic pesticides and their residues can be mainly found in the surface of the crops. Thanks to the activity against a wide number of fungal diseases its use is extended to a high number of crops.d3,d4.

The current dithiocarbamates are: maneb, mancozeb, metiram, propineb, thiram and ziram.

Some of the dithiocarbamates show a certaing degree of toxicity to mammals, marine invertebrates, fishes, earthwoms and birds, depending on which dithiocarbamate is being considered d2 The main metabolites from dithiocarbamates area Ethyenthiourea (ETU) and Propylenthiourea (PTU) 4, these two metabolites has been found to be cancinogenic to rats 5 and inhibitors of the thyroid hormone and cause of some problems with the blood and liver 6, between another possible ppathogenic effects 4. The toxicity in the long term for mammals can affect the thyroids, but again, the toxicity depends on which dithiocarbamate we are refering to d7.

The current definition and way of reporting results for these pesticides are as "Dithiocarbamates (dithiocarbamates expressed as CS2, including maneb, mancozeb, metiram, propineb, thiram and ziram)"d8.

Some of the dificulties that this analysis shows is that due to the low solubility in multiresidues solvents and the low stability the require a single residue method d2,additionaly during the preparation of the sample up to a 100% of the dithiocarbamates can be lost if done at room temperture and if some artificial rubber is used there have been cases when they have contaminated the samples with dithiocarbamates, risking the possible false positive or erroneous results d9.

Why participate in a proficiency test?

There are many reasons to schedule these quality controls, the participation in international proficiency tests helps laboratories detect improvements and ensure the results are reliable.

As of today, one of the main goals for any laboratory is increase its client’s trust in their analysis procedure and results obtained, checking that equipment, personel, solvents and all the steps and parts involved in the analysis are working as intented, providing trustworthy and realiable results.

As a laboratory its is now more important than ever to be able to obtain results with precision and accuracy to help your clients commercialice products safe for the end-user.

The continuous participation in proficiency tests can help you detect bias and check if any change or improvement made as an effect on the results obtained.

TestQual's international proficiency tests are a great and reliable service to help you check your results against laboratories from all around the world, helping you detect any deviation to correct it and ensure your clients continuous quality controls and improvements are being monitored by participating and checking your results against other laboratories.

Summary of the proficiency test

All the information about this PT can be found in the protocol, which can be downloaded from a link located in the right column of this page. 

This proficiency test will consist in a single round with a single sample, the amount of sample (approx. 250g) to be distributed can be found in the protocol of this PT. If needed and justified, more amount of sample can be requested to the coordinator of the PT. Additional charges might apply.

The range of concentration for the target analytes of this proficiency test will be:

Approximately between 10 µg/Kg and the MRL.

The target standard deviation 30% for the analytes can be checked in the protocol.

For this PT the parameters to be analyzed are: 

PT Scheduled calendar

Check the right column of this page, in the “Dates” section.

*These dates are orientative and always will have to be checked in the protocol of the PT and the news in our webpage. Only participants inscribed in the proficiency test will receive the sample instructions/recommendations and the definitive date for the distribution of samples.

**PT is considered useful to a participant if a a certain % (internally determined according to our procedure) of present/spiked analytes will be studied.

Accreditation and standards

·Standars in which this proficiency test is based/accredited:

·UNE-EN ISO/IEC 17043:2010 General requirements for proficiency testing. (Proficiency test ACCREDITED). Check our scope of accreditation here.

·UNE-EN ISO/IEC 15328:2015 Statistical methods for use in proficiency testing by interlaboratory comparison

· HARMONIZED PROTOCOL FOR THE PROFICIENCY TESTING OF (CHEMICAL) ANALYTICAL LABORATORIES

·SANTE Guide into force: ANALYTICAL QUALITY CONTROL AND METHOD VALIDATION PROCEDURES FOR PESTICIDE RESIDUES ANALYSIS IN FOOD AND FEED

· Quick Polar Pesticides Method (QuPPe) latest version.

Why international proficiency tests with TestQual?

·18 years of experience in proficiency tests since our foundation.

·Possibility, if previously requested and applies (Multi-method, single residues, different analyte families,etc.) , to issue independent reports per group of analytes (groups are decided by TestQual).

·International proficiency tests with participants from different countries (currently up to 5 continents).

·Transparency: Results from spiking and quality controls (homogeneity, stability) available for any participant that requests it.

·Expanding network of distributors to give a better client service, using local language and within your time zone. If your country still does not have a distributor, please, contact us, we can still accept your order.

·We take care of all aspects of the shipping, so you can focus on the analysis.

· We are available at any time and any direct consult to TestQual has an inferior response time of 24h (working days).

·We do not publish beforehand the price of shipping because we are constantly negotiating with providers and couriers to improve and adjust our prices. However, if you need a closed price in the quote and need to know the shipping costs, please, let us know and we will include it.

How to apply and get your laboratory code

Those laboratories that want to participate and are not registered on our website can register through this link: START REGISTRATION

If your laboratory is already registered on our website you can start your application by clicking the link situated at the top or bottom of this page, in PARTICIPATE, once you have logged in you will have to enter your Limit of Quantification (LOQ) for the parameters that have to be studied. The analytes with LOQ equal to NA (NOT ANALYSED) will NOT appear in the website when submitting the results of the PT.

Once the application has been sent, as soon as possible (usually 24h) you will receive an email with your laboratory code for the participation in the PT.

**PT is considered useful to a participant if a a certain % (internally determined according to our procedure) of present/spiked analytes will be studied.

Contact us

If you have any doubt, if you want to get a quote or if we can help you in any other way, we are looking forward to helping you:

Thank you very much for your interest/trust in TestQual and our international proficiency tests.

If you want to receive a sample and participate click on the button "Participate" down below.