Compilation of Analytical Observations Reports
The table below compiles various observations made during the analysis of pesticide residues.
Laboratories within the NRL/OL-Network are encouraged to submit their own analytical observations. The idea is to gradually build up a large collection of observations with the aim to conserve knowledge and to offer laboratories a useful and practical source of information.
Further Information
| Compound(s) | No. of Method Finder List/Version/Date of Update | Link | |
|---|---|---|---|
| Toxicologically critical Abamectin Emamectin Diclofop Haloxyfop Gamma-Cyhalothrin 3-Hydroxycarbofuran Fentin Amitrole Nicotine PTU Diquat Topramezone Additional Ethoxyquin-Dimer Trifluoracetic acid Chlorate Perchlorate Phosphonic acid Triazole-acetic acid Triazole-lactic acid Triazole-alanine Paraquat Melamine Cyanuric acid |
SRM-44/(V2)/10.03.2021 | Analytical Observations Report | |
| Short Description: A method was developed allowing the analysis of highly toxic compounds (for which the default MRL of 0.01 mg/kg is considered unsafe for children up to 16 weeks of age) in infant fomulae and milk. Several additional compounds, estimated being relevant to milk-based products were also included in this study. The EURL-SRM focused on compounds not amenable to multiresidue methods. Spiking levels for validation experiments on infant formulae were chosen to be lower than the concentrations considered unsafe. The following compounds were included in the study: Critical compounds covered by QuEChERS and LC-MS/MS: Abamectin, Emamectin, Diclofop, Haloxyfop, Gamma-Cyhalothrin, 3-Hydroxycarbofuran and Fentin. Critical compounds covered by QuPPe and LC-MS/MS: Amitrole, Nicotine, PTU, Diquat and Topramezone. Additional compounds covered: Ethoxyquin-Dimer, Trifluoracetic acid, Chlorate, Perchlorate, Phosphonic acid, Triazole-acetic acid, Triazole-lactic acid, Triazole-alanine, Paraquat, Melamine and Cyanuric acid. Recoveries of Fentin using CEN QuEChERS were low, but they were nearly quantitative using the FA-QuEChERS procedure, where acetonitrile with 1 % formic acid and no citrate buffer salts are used. The results of the analysis of numerous samples of infant formulae and milk from the market can be found under » Report on Residue Findings in Infant Formulae and Milk (SRM-Compounds) |
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| Compound(s) | No. of Method Finder List/Version/Date of Update | Link | |
|---|---|---|---|
| Acidic Pesticides | SRM-02/(V1)/20.05.2015 | Analytical Observations Report | |
| Short Description: Two methods, the QuEChERS method (EN 15662) and the acidified-QuEChERS method (A-QuEChERS) were tested for the analysis of acidic pesticides. A-QuEChERS involved extraction with acetonitrile containing 1 % formic acid and the use of partitioning salts composed of NaCl and MgSO4 only. Recovery experiments were conducted on cucumber, grapes and maize. No alkaline hydrolysis step was conducted and thus the focus was on free acids only. Most compounds showed satisfactory recovery figures by both methods. There were some pesticides, however, where average recoveries using QuEChERS were unsatisfactory (< 70 %) using QuEChERS but satisfactory using A-QuEChERS. | |||
| Compound(s) | No. of Method Finder List/Version/Date of Update | Link | |
|---|---|---|---|
| Acidic Pesticides and other compounds requiring Hydrolysis to break up esters and/or conjugates (previously: "Acidic Pesticides following hydrolysis") 2,4-D, Haloxyfop and other carboxylic acid pesticides - Esters thereof - conjugates thereof - Glucosides thereof 2-phenylphenol |
SRM-43/(V2)/21.04.2021 | Analytical Observations Report | |
| Short Description: A document dealing with the analysis of pesticides requiring the conduction of a hydrolysis step to cover the full residue definition is introduced. A short general overview on conjugates is given but the focus is on pesticides with carboxylic groups and the possibilities to break up conjugated and ester-bound residues. Both alkaline hydrolysis and enzymatic hydrolysis (with porcine liver esterase) are discussed. Three different QuEChERS-integrated hydrolysis procedures are applied to hydrolyze resistant esters: For "simple" commodities (like most fruits and vegetables) the hydrolysis conditions remain as described in CEN-QuEChERS (0.25 mmol/mL* / 40 °C / 30 min). For cereals and pulses harsher conditions are needed. The base amount is doubled but the temperature is kept at 40 °C to avoid clumping, therefore the reaction time is extended (0.5 mmol/mL* / 40 °C / 120 min). For "complex" commodities, such as citrus fruits, the harshest conditions are employed (0.5 mmol/mL* / 60 °C / 60 min). For commodities of animal origin, 1 mL 5N NaOH is added (0.25 mmol/mL* / 60 °C / 60 min). *calculated on the basis of 20 mL volume after addition of acetonitrile. To give a hint on the extend of conjugation within real samples and the impact of hydrolysis on the release of acidic pesticides, a compilation of results from the analysis of incurred 2,4-D, Fluazifop and Haloxyfop, with and without applying hydrolysis, is presented. |
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| Compound(s) | No. of Method Finder List/Version/Date of Update | Link | |
|---|---|---|---|
| Amitraz Metabolite (4-amino-3 methylbenzoic acid) |
SRM-41/(V1)/21.06.2019 | Analytical Observations Report | |
| Short Description: Based on information from metabolism studies 4-amino-3 methylbenzoic acid was identified as a potential marker for amitraz-use in chicken farms. Two CEN-QuEChERS-based methods for the analysis of 4-amino-3 methylbenzoic acid in eggs were developed, one concerning the analysis of the free compound and one involving a hydrolysis step to release conjugated residues. 18 samples from farms suspected to potentially contain Amitraz residues were tested by these two methods, however, none of these samples was found to contain any measurable residues of 4-amino-3 methylbenzoic acid. | |||
| Compound(s) | No. of Method Finder List/Version/Date of Update | Link | |
|---|---|---|---|
| AMTT Metabolite of Tritosulfuron | SRM-35/(V1)/30.03.2017 | Analytical Observations Report | |
| Short Description: AMTT results from the use of tritosulfuron. It is both a metabolite of tritosulfuron as well as an impurity in formulations (specification max. 0.2 g/kg) . Due to the high toxicity of AMTT, EFSA in its reasoned opinion on Tritosulfuron in 2015, proposed to distinctly regulate AMTT proposing very low MRLs at 0.001 mg/kg for cereals and various products of animal origin. Based on the metabolism study it was concluded that the residues in milk were expected to be so low, that no exceedances of the toxicological thresholds are expected. The development of a method for milk that is validated at 0.0005 mg/kg was advised. With regulation 2016/2016/EC, applicable from 14 January 2017 onwards, the maximum residue level of AMTT for milk and cereals was set at 0.001 mg/kg and for all other products at 0.01 mg/kg. In the preamble of this regulation it is indicated that “Analytical methods to achieve the lowest possible LOD need to be developed for AMTT. Once those methods are available, the levels set by this Regulation may be reviewed at any stage”. Initial tests have shown that using unmodified QuEChERS and routine instrument settings of an older generation LC-MS/MS instrument (ABI-Sciex 4000), LOQs below 0.01 mg/kg are difficult to achieve, especially for dry commodities, where the sample weight is reduced to 5 g. |
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| Compound(s) | No. of Method Finder List/Version/Date of Update | Link | |
|---|---|---|---|
| Boscalid metab. M510F01, Fenpropidin metab. CGA289267 Isoxaflutole metab. RPA202248 Isoxaflutole metab. RPA203328 Spiroxaminecarboxylic acid Fenpropimorph carboxylic acid (BF-421-2) Trifloxystrobin metab. CGA 321113 Dimoxystrobin metab. 505M09 |
SRM-36/(V1)/25.04.2018 | Analytical Observations Report | |
| Short Description: Numerous pesticides are being annually re-evaluated according to Article 12 of Regulation 396/2005/EC. Where indicated, new MRLs and sometimes also new residue definitions are set. Within this framework the EURLs are involved in assessing the analytical amenability of residue definitions proposed for enforcement purposes and in elaborating possible consensus LOQs for the main commodity classes, which are considered when setting residue limits for products where no residues are expected (MRL*s). Within this context, the EURL-SRM mainly focuses on pesticides and relevant metabolites, which are known to pose problems in analysis and are thus considered “difficult” or non-amenable to multiresidue methods. It is first tested whether the analytes or residue definitions can be analyzed by introducing, preferably simple, modifications to traditional multiresidue methods (MRMs, mainly QuEChERS), and if not new methods are developed. Modifications of MRMs may entail various measures to prevent degradation or improve extractability of residues (e. g. adjustment of pH, addition of substances and adjustment of extraction temperature and time), cleavage reactions to release conjugates, special measurement conditions and other. In case of highly polar pesticides, that do not readily partition into the acetonitrile phase of the QuEChERS method, the QuPPe method, which does not involve a partitioning step, or variations thereof are tested. The present analytical observations report deals with a number of metabolites that are relevant to products of animal origin and that, for various reasons, are expected to pose difficulties in analysis. |
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| Compound(s) | No. of Method Finder List/Version/Date of Update | Link | |
|---|---|---|---|
| Captan & THPI (tetrahydrophthalimide) and Folpet & PI (phthalimide) |
SRM-07/(V3)/06.07.2017 SRM-42/(V1)/30.06.2019 SRM-49/(V1)/16.03.2023 |
SRM-07 (GC-MS/MS) Excel files to calc. conc. of parents & degradants, based on GC-MS/MS data generated following calibration approaches described in SRM-07: SRM-07-ExtCal (parents+degrad. by GC-MS/MS) SRM-07-StdAdd (parents+degrad. by GC-MS/MS) SRM-42 (par.+degrad.; LC-MS/MS; APCI or ESI) SRM-49 (THPI+PI by LC-MS/MS; ESI-pos) |
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| Short Description of SRM-07 (GC-MS or GC-MS/MS): This document describes approaches for the analysis of Captan and Folpet in QuEChERS extracts via GC-MS or GC-MS/MS. Different approaches for correcting the results of the parent molecules for matrix effects during GC analysis or for losses during the entire procedure are presented and discussed. In addition two approaches for analyzing Captan and Folpet next to their legally relevant metabolites Tetrahydrophthalimide (THPI) and Phthalimide (PI) are presented and discussed. Short Description of SRM-42 (LC-MS/MS in APCI-neg. and ESI-neg. modes): Various possibilities for the LC-MS/MS analysis of Captan/THPI and Folpet/PI were studied employing APCI and ESI interfaces. LC-MS/MS analysis circumvents problems related to GC-analysis but further efforts to improve sensitivity are required. The active hydrolysis of Captan and Folpet to their respective degradants (THPI and PI), was also studied aiming to reduce the number of analytes to be measured. Unfortunately, conversion yields were often not satisfacory and further studies are needed. Short Description of SRM-49 (LC-MS/MS in ESI-pos. mode): A simple and sensitive method for the analysis of PI and THPI was developed based on QuEChERS extraction and LC-MS/MS determination in the ESI-pos. mode using a C18 column and a slightly acidic eluent without the addition of ammonium buffer salts for separation. Validations of THPI and PI in cucumber, grapes, wheat flour and peanut butter were successful down to 0.005 (~0.01 mg/kg expressed as corresponding parent). In wheat flour and peanut butter, THPI validation at 0.005 mg/kg and 0.010 mg/kg was only successful for one single mass-transition (m/z 152/81) as the second one (m/z 152/79) showed MS-interferences compromising identification. Further experiments are planned to increase selectivity and enable identification of THPI at low levels, both at the sample preparation (i.e. cleanup) and at the measurement stage. Overall Conclusion: The analysis of Captan (sum) and Folpet (sum) requires special care. Homogenates of samples should not be left standing at elevated temperatures to avoid degradation. Captan and Folpet show a rather poor sensitivity in LC-MS/MS, not allowing accurate analyses at low levels, so GC-analysis needs to be endeavored. Using GC, Captan and Folpet can be sensitively analyzed but matrix effects need to be properly addressed to as these may lead to highly inaccurate results (see SRM-07). Also, care should be taken to reduce thermal decomposition in the hot injector which would lead to false negative results (see SRM-07). This thermal decompositions leads to the formation of PI and THPI, and if this aspect is not considered the GC-results of PI and THPI are overestimated. This effect is more pronounced if the parents are present at excess levels (see SRM-07). Accurate analysis of THPI and PI next to their parents is possible using a special calibration approach that deducts the share of PI and THPI formed from the decomposition of the parents within the GC-injector (see GC-Analysis of Captan-Folpet-THPI-PI via External Calibration and GC-Analysis of Captan-Folpet-THPI-PI via Standard Addition). A convenient and accurate analysis of THPI and PI, can be accomplished via LC-MS/MS in the ESI pos. mode (see SRM-49). As Captan and Folpet may degrade to THPI and PI at various stages of the procedure including the extract itself, it is important to analyse THPI/PI and Captan/Folpet from the same extract and within a reasonably short time distance. |
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| Compound(s) | No. of Method Finder List/Version/Date of Update | Link | |
|---|---|---|---|
| Carbofuran, Benfuracarb, Furathiocarb, Carbosulfan, 3-OH-Carbofuran |
SRM-33/(V1)/20.04.2016 | Analytical Observations Report | |
| Short Description: The final method developed is as follows: (a) Extraction: Apply the citrate buffered QuEChERS (EN 15662). Weigh 10 g of frozen fruit or vegetable homogenate or 5 g of cereals; adjust water content to 10 mL where necessary, add 10 mL acetonitrile and internal standard (e. g. 100 µL of an appropriately concentrated solution of Carbofuran-D3 ). Shake 15 min using a mechanical shaker. Add a mixture of 4 g MgSO4, 1 g NaCl, 1 g trisodium citrate dihydrate and 0.5 g disodium hydrogen citrate sesquihydrate, shake 1 min and centrifuge. (b) Cleanup: Cleanup via dispersive SPE is optional for fruits and vegetables. (c) Hydrolysis: Transfer 1 mL of raw extract into vial and add 10 µL 5N H2SO4. Nearly quantitative transformation of BF, CS and FT into CF is achieved by heating the vials for 3 h at 80 °C. (d) LC-MS/MS analysis: For screening purposes CF, 3-OH-CF as well as BF, FT and CS may be analyzed by LC-MS/MS directly in QuEChERS raw extracts or cleaned-up extracts. In case of positive findings the hydrolysis step can be conducted as described above and LC-MS/MS analysis of CF repeated. 1 mL final extract will represent approximately 1 g matrix. For measurement conditions and recovery figures see "EURL-SRM - Analytical Method Report (Analysis of Residues of Carbofuran (sum) using QuEChERS method)". |
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| Compound(s) | No. of Method Finder List/Version/Date of Update | Link | |
|---|---|---|---|
| Risk of False Positives of Chloridazon-Desphenyl in Honey by LC-MS/MS | SRM-51/(V1)/ - | Analytical Observations Report | |
| Short Description: This Analytical Observations Report highlights the risk of false positive chloridazon-desphenyl results when analyzing honey extracts. LC-MS/MS signals of chloridazon-desphenyl where interfered on all three mass transitions at the retention time of chloridazon-desphenyl. Interestingly, two of these mass-transitions showed an ion-ratio within the acceptable limits. The unusually high frequency of apparent findings within the frame of a pilot monitoring study on honey combined with the questionable ion ratio raised questions regarding the validity of these apparent findings and stressed the need to run confirmatory analyses. The samples were re-analyzed by a newly developed LC-MS/MS method on different HILIC column as well as by a method using supercritical fluid chromatography (UPC2-MS/MS). With these techniques, chloridazon-desphenyl could be chromatographically separated from matrix interferences. A confirmatory analysis by LC-ToF-MS was, however, not fully conclusive. | |||
| Compound(s) | No. of Method Finder List/Version/Date of Update | Link | |
|---|---|---|---|
| Dicofol | SRM-11/(V1)/23.04.2013 | Analytical Observations Report | |
| Short Description: Dicofol is often extensively (often completely) degraded during sample preparation and GC-analysis. This often results in poor recoveries and poor analytical precision. The use of isotope-labeled dicofol (e.g. dicofol-D8) as internal standard (ILIS) is the most efficient and convenient way to eliminate most sources of errors. If added to the final extract the ISTD can match for any decomposition and signal fluctuations in GC. If added at the beginning of the procedure it will also match for any losses during extraction and cleanup. Even when using the IL-IS it is important that dicofol does not disappear completely. Keeping the pH low during extraction and the final extract is helpful. If dSPE with PSA sorbent is performed re-acidification should be rapid. Also helpful is the use of Analyte Protectants (APs) that help to reduce degradation-rates during GC. | |||
| Compound(s) | No. of Method Finder List/Version/Date of Update | Link | |
|---|---|---|---|
| Dimethoate Metabolites | SRM-40/(V1)/28.04.2019 | Analytical Observations Report | |
| Short Description: An analytical method for 6 Dimethoate and Omethoate metabolites (III, X, XI, XII, XX and XXIII) was developed and the residue situation was studied based on the analysis of 1778 market samples. 98 out of 1778 samples (5.5 % overall) were found to contain Dimethoate-related residues. Their residue profiles suggested that in all cases Dimethoate was employed in the field. Metabolite X was contained in all these 98 samples, being in 39 cases contained at levels ≥ 0.01 mg/kg. In contrast, dimethoate and omethoate were encountered at levels ≥ 0.01 mg/kg in only 3 and 4 samples respectively. Based on these results the inclusion of Metabolite X (O-desmethyl Dimethoate) as an additional marker for controlling proper use of dimethoate should be considered. Metabolites XI was also very often encountered (61 % of samples) but typically at very low levels, it was present at levels ≥ 0.01 mg/kg in only 4 samples. Metabolite XX was found in 12 % of the samples with 3 of them containing it at levels ≥ 0.01 mg/kg. The other three metabolites (III, XII, XIII), were not encountered in any sample. This information should hopefully be of use in future risk assessment and risk management actions on dimethoate. | |||
| Compound(s) | No. of Method Finder List/Version/Date of Update | Link | |
|---|---|---|---|
| Dithianon | SRM-13/(V2.1)/09.05.2016 see also under Methods (SRM-12) |
Analytical Observations Report | |
| Short Description: Dithianon often shows low or variable recovery rates from various commodities and especially from those exhibiting high natural pH. Recoveries become acceptable when conducting QuEChERS under acidic conditions and skipping the cleanup with PSA. Stability in QuEChERS extracts is improved when pH is low. | |||
| Compound(s) | No. of Method Finder List/Version/Date of Update | Link | |
|---|---|---|---|
| Dithiocarbamate as CS2 | SRM-14/(V3)/ - | Analytical Observations Report | |
| Short Description:The updated document describes an adjusted procedure for the analysis of dithiocarbamate residues in fruits, vegetables and cereals via the common moiety (carbon disulfide = CS2) approach, involving cleavage with HCl/SnCl2, partitioning of CS2 into isooctane, and measurement by GC-techniques. The procedure described in the previous version (V2) provided satisfactory recovery rates for thiram, but there are indications of insufficient recovery rates for polymeric dithiocarbamates (such as Metiram, Zineb and Propineb). Therefore, the hydrolysis time, reaction temperature and sample weight were adjusted resulting in an increased reagent-to-sample weight-ratio. The procedure was furthermore scaled down leading to a reduced consumption of chemicals. GC-MS/MS conditions were additionally introduced. Using this approach, Metiram, Propineb, Thiram, Zineb and Ziram were successfully validated at 0.02 mg/kg CS2 in various low-fat content commodities of plant origin. | |||
| Compound(s) | No. of Method Finder List/Version/Date of Update | Link | |
|---|---|---|---|
| Dodine | SRM-15/(V1)/23.02.2015 | Analytical Observations Report | |
| Short Description: Using QuEChERS and LC-MS/MS for measurement Dodine often shows overestimated recovery rates when quantified using calibration solutions prepared in pure solvents. The effect is attributed to the tendency of Dodine to interact with active surfaces, especially in absence of competitive matrix components, and can vary considerably from instrument to instrument. The effect typically temporarily improves when cleaning the tubing within the injector. To effectively eliminate the effect calibration standards prepared from extracts of blank commodities should be used. Alternatively acidification of solvent-based calibration standards (e.g. with formic acid) will also help to minize these interactions. | |||
| Compound(s) | No. of Method Finder List/Version/Date of Update | Link | |
|---|---|---|---|
| Ethoxyquin | Plant Origin SRM-21/(V2)/30.03.2015 | Analytical Observations Report | |
| Short Description: Ethoxyquin typically shows notoriously low recoveries in commodities with low antioxidative activity. The addition of the antioxidant ascorbic acid to the analytical portion of the sample prior to QuEChERS extraction helps to increase recoveries. To further minimize the losses during the analytical procedure it is further recommended to add ascorbic acid already prior to the cryogenic milling step (1 g per 100 g sample). | |||
| Animal Origin SRM-24/(V1)/17.05.2016 | Analytical Observations Report | ||
| Short Description: The use of EQ as animal feed additive can lead to residues in food of animal origin such as poultry meat and eggs as well as in farmed fish and shrimp. EQ converts into a multitude of transformation products including Ethoxyquin Dimer (EQDM), Ethoxyquin Quinone Imine (EQI or QI) and Dihydroethoxyquin (DHEQ). Some of these metabolites also exhibit antioxidant properties themselves. In recovery experiments on wild Atlantic salmon AA showed a strong protective effect on EQI and a weaker but well notable protection effect on EQ parent and the metabolite DHEQ. EQDM was more stable and not notably affected by the addition of AA. In contrast, the impact of AA on EQ extraction yields from farmed salmon was minimal. We assume that this is due to the high levels of other antioxidants added to fish feed and accumulating in farmed fish. Recoveries for QI could be improved from 11 % when no AA was added prior or during extraction to 96 % when AA was added to the frozen salmon prior to QuEChERS extraction. Analysis of farmed salmon showed only residues of EQ and EQDM. To be on the safe side, addition of AA prior to QuEChERS extraction or even during cryogenic milling is still recommended. | |||
| Compound(s) | No. of Method Finder List/Version/Date of Update | Link | |
|---|---|---|---|
| Ethylene oxide | Plant Origin SRM-45/(V1)/17.12.2020 | Analytical Observations Report | |
| Short Description: Two methods, one based on QuEChERS and one on QuOil, are presented allowing the simultaneous analysis of Ethylene oxide (EO) and its reaction product 2-Chloroethanol (2-CE) in sesame. Following a standard dSPE cleanup the samples are measured by GC-MS/MS. The extraction of 2-CE from sesame, was found to be considerably delayed compared to other analytes. It is thus of high importance to use extraction aids (e. g. stainless steel balls) during extraction to disintegrate the sample and improve the accessibility of the residues. Sesame samples from the market only contained 2-CE at detectable levels | |||
| Compound(s) | No. of Method Finder List/Version/Date of Update | Link | |
|---|---|---|---|
| Fluoride ion | SRM-50/(V1)/02.03.2023 | Analytical Observations Report | |
| Short Description: Fluoride is a natural component in food commodities and a trace element in human nutrition. Moreover, fluoride anion is a useful marker compound indicating fumigations with sulfuryl fluoride, which is applied for disinfestation of dry food commodities, e.g. before transportation. Sulfuryl fluoride is an approved active substance within the EU with applications being authorized in various member states. MRLs for both, sulfuryl fluoride and the fluoride ion, are established in Regulation (EC) No 396/2005. In this observations report three different methods for the determination of fluoride ion in food, all em-ploying ion-selective electrodes (ISE) for detection, were established. The approaches tested were the following: 1) Direct measurement of fluoride in QuPPe extracts by ISE (mainly used for commodities with high water content) 2) Microdiffusion (MD) of fluoride from dry commodities into a trapping solution and measurement of the trapped fluoride by ISE 3) Drying of commodities with high water content with the help of a moisture analyzed followed by MD of fluoride into a trapping solution and its measurement by ISE. The feasibility of using these approaches for screening of fluoride, as well as for routinely controlling MRL compliance was checked. |
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| Compound(s) | No. of Method Finder List/Version/Date of Update | Link | |
|---|---|---|---|
| Guazatine | SRM-38/(V1)/15.06.2018 | Analytical Observations Report | |
| Short Description: Guazatine is a non-systemic contact fungicide that is also used as a repellent. It consists of a complex mixture of different oligomers composed of octamethylene bridges connecting randomly guanylated primary and/or secondary amino groups. With all Guazatine components being strongly basic and highly polar, recovery rates by the citrate buffered QuEChERS method [QuEChERS EN15662], were extremely low. Recoveries using the QuPPe method [EURL-SRM-QuPPe], which does not involve any partitioning step and is thus suitable for polar compounds, were surprisingly also very low. Besides the difficulties with achieving good recoveries the coverage of the full residue definition "Guazatine (Guazatine acetate, sum of components)" is also challenging due to the complexity of the Guazatine mixture. Even if one or a few marker compounds are quantified, extrapolations to Guazatine (sum) is associated with uncertainty for a number of reasons including a) the reported fluctuations in the in the composition of the technical mixture used to produce Guazatine-formulations; b) the potential differences in the degradation rates of the individual Guazatine components within the crops; and c) the variable, and to a certain extent uncertain composition of the available analytical standards of Guazatine mixtures. The present study aimed to develop a method allowing the analysis of the main Guazatine components (preferably via LC-MS/MS) and to examine whether the introduction of a different residue definition based on the sum of a few selected marker compounds (with or without extrapolation to total Guazatine) would be a feasible option from the analytical point of view. The present paper is an interim report of an ongoing study and will be periodically updated. |
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| Compound(s) | No. of Method Finder List/Version/Date of Update | Link | |
|---|---|---|---|
| Meptyldinocap | SRM-47/(V1.2)/updated August 2022 | Analytical Observations Report | |
| Short Description: A simple and sensitive method for the analysis of Meptyldinocap (sum), involving transformation of Meptyldinocap to the corresponding phenol (2,4-DNOP) in sample extracts was developed. Following extraction via QuEChERS or QuOil the extracts are subjected to a simple alkaline hydrolysis overnight. Following neutralization, measurement is conducted via LC-MS/MS in the ESI(neg) mode on a C18 column. A direct measurement of Meptyldinocap and 2,4-DNOP individually via LC-(ESI-neg)-MS/MS is also possible. Meptyldinocap undergoes fragmentation to the phenol within the ion source. Parent and phenol can thus be analysed in one chromatographic run and are even detected within the same MRM-traces. Unfortunately, the detection sensitivity of Meptyldinocap (via its in-source fragment) is rather poor, which compromises overall sensitivity of the method. The approach involving alkaline hydrolysis to 2,4-DNOP is much more sensitive overall. Validation of Meptyldinocap, following its conversion to the corresponding phenol (2,4-DNOP), was successful in cucumber, grapes, wheat flour, peanut butter and bovine liver at 0.005 mg/kg. |
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| Compound(s) | No. of Method Finder List/Version/Date of Update | Link | |
|---|---|---|---|
| Organotins | SRM-16/(V1)/22.04.2013 | Analytical Observations Report | |
| Short Description: Using QuEChERS, organotin compounds tend to give low recoveries in various types of commodities with high pH commodities being affected the most. Recovery improvements were achieved by lowering the pH during the extraction step. Various versions of the QuEChERS method entailing different acidification approaches were tested. All showed a positive impact on the recoveries of Fenbutatin oxide, Cyhexatin and Fentin. | |||
| Compound(s) | No. of Method Finder List/Version/Date of Update | Link | |
|---|---|---|---|
| Phthalimide Tetrahydrophthalimide |
SRM-49/(V2)/ 23.03.2023 | Analytical Observations Report | |
| Short Description: A simple and sensitive method for the analysis of PI and THPI was developed, involving QuEChERS extraction and LC-MS/MS determination in the ESI-pos. mode using a C18 column for separation. Overall, it could be shown, that THPI and PI can be potentially incorporated into the multiresidue scheme of labs. If not, the presented approach may also run as a standalone procedure that is employed following detection of a marker compound during routinely analysis (e.g. detection of Captan and/or THPI by a GC-based method). For more information see above under "Captan & THPI and Folpet & PI |
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| Compound(s) | No. of Method Finder List/Version/Date of Update | Link | |
|---|---|---|---|
| Prochloraz BTS 44596, BTS 44596, BTS 40348, BTS 9608, 2,4,6-Trichlorophenol |
SRM-19/(V3)/30.07.2016 | Analytical Observations Report | |
| Short Description: The current residue definition of Prochloraz requires the conduction of a hydrolysis step to transform a number of Prochloraz metabolites to 2,4,6-Trichlorophenol. In a recent reasoned opinion EFSA proposes a new residue definition which includes the parent and two metabolites (BTS 44595 and BTS 44596) which can all be covered by multiresidue methods. Several experiments were conducted showing that the consideration of the above Prochloraz metabolites within the current residue definition can be quite tricky from the analytical and calculative points of view and that certain aspects have to be considered in LC-MS/MS and GC-MS analysis. Analysis of samples from the market shows prochloraz being the most prominent residue component (average share of summed residue expr. as prochloraz was 64%). Among the tested metabolites BTS 40348 is by far the most prominent (29% avg. share). BTS 44596 (4% avg. share), BTS 9608 (3% avg. share) and BTS 44595 (41% avg. share) follow. Prochloraz and its metabolites tend to decompose to 2,4,6-TCP within the hot GC injector. GC analysis of 2,4,6-TCP in sample extracts via GC leads to highly overestimated 2,4,6-TCP results. Note: the Residue definition changed in 2020 and now includes the parent and the metabolites BTS 44595 (M201-04) and BTS 44596 (M201-03). |
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| Compound(s) | No. of Method Finder List/Version/Date of Update | Link | |
|---|---|---|---|
| Propamocarb | SRM-20/(V1)/24.10.2012 | Analytical Observations Report | |
| Short Description: Propamocarb showed a very strong signal enhancement effect in LC-MS/MS analysis of cucumber and lettuce extracts. Matrix effects could be eliminated using a more polar stationary phase where Propamocarb is more strongly retained and obviously better separated from those matrix components inducing signal enhancement. | |||
| Compound(s) | No. of Method Finder List/Version/Date of Update | Link | |
|---|---|---|---|
| Propineb Propylene diamin |
SRM-48/(V1)/ - | Analytical Observations Report | |
| Short Description: A method for the analysis of propineb residues as propylenediamine (1,2-diamonopropane = PDA) is presented. The method starts with the traditional reductive cleavage with HCl/SnCl2 (during which propineb is converted to CS2 and PDA) and continues with a QuEChERS-like partitioning step under alkaline conditions. PDA measurement involves ion-pair LC separation on a C18 column followed by electrospray ionization in the positive mode and MS/MS analysis. Validation of propineb was successful in kiwi at 0.05 mg/kg (expressed as PDA), which corresponds to the current MRL of 0.05 mg/kg (Reg. 396/2005/EC). Even though the analyses of CS2 and PDA have overlapping analytical steps, it is recommended conducting the PDA-analysis after a positive screening for PTU which proved to be a more suitable trigger for the conduction of the PDA analysis compared to CS2, which mostly originates from other types of dithiocarbamates or from natural products (in certain crops such as brassica). |
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| Compound(s) | No. of Method Finder List/Version/Date of Update | Link | |
|---|---|---|---|
| Pymetrozine | SRM-32/(V1)/18.04.2016 | Analytical Observations Report | |
| Short Description: Pymetrozine shows pH-dependent recovery rates using the QuEChERS method. pH should optimally exceed 5 for the Pymetrozine recovery rates to be well above 70 %. pH can be increased by replacing the citrate salts with acetate salts. The following mixtures were found to work well for 10 g sample: 4 g MgSO4 +1 g NaCl + 0.5 g sodium acetate and 4 g MgSO4 +1 g Mg-Acetate. | |||
| Compound(s) | No. of Method Finder List/Version/Date of Update | Link | |
|---|---|---|---|
| Pyridate | SRM-22/(V1)/30.03.2015 | Analytical Observations Report | |
| Short Description: The degradation of Pyridate into pyridafol (CL 9673) during QuEChERS sample preparation was studied. It was shown that Pyridate degrades at high pH levels, for example when perfoming d-SPE cleanup with PSA-sorbent. Furthermore, being slightly acidic in nature, Pyridafol experiences losses during the dSPE step when PSA-sorbent is used. | |||
| Compound(s) | No. of Method Finder List/Version/Date of Update | Link | |
|---|---|---|---|
| Quaternary Ammonium Compounds (QACs) | SRM-26/(V6)/23.02.2023 | Analytical Observations Report | |
| Short Description: Background contaminations of quaternary ammonium compounds (QACs) with variable intensity are often reported. A simple and practical approach for separating these background contaminations deriving from the LC-MS/MS system is presented. The approach involves the installation of a trap column between the pump and the autosampler of the LC-system. Any QAVs contaminants eluting from the system in-between chromatographic runs (e.g. during column equilibration), are trapped onto this trap-column and prevented from accumulating at the beginning of the analytical column or pre-column. During the chromatographic run, these contaminants will eventually also elute through the analytical column, but they will experience additional retention (in the trap column), and will thus separate from their analogues introduced through the injection of sample extracts. Using this approach, BAC-C8, -C10, -C12, -C14, -C16 and –C18 as well as DDAC-C8, -C10 and –C12 were successfully validated at 0.005 mg/kg and 0.010 mg/kg in matrices of all four main matrix groups of plant origin. In the case of DDAC-C10, low-level validations were considered invalid as the blank extracts contained DDAC-C10 levels > 30 % of the spiking level, thus not fulfilling the requirements of Document Nº SANTE/11312/2021. The presented approach can be easily transferred to other areas where background contaminations deriving from the LC-system may occur, for example when analyzing other ubiquitous compounds, such as per- and polyfluoroalkyl compounds and plasticizers. |
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| Compound(s) | No. of Method Finder List/Version/Date of Update | Link | |
|---|---|---|---|
| Sulfuryl Fluoride | SRM-37/(V1)/30.04.2018 | Analytical Observations Report | |
| Short Description: Sulfuryl Fluoride was introduced in the 1950s as a fumigant for the control of insect pests in wood especially termites. It has also been used to control rodents. Following the Montreal agreement and the resulting decrease in the use of Methyl Bromide Sulfurid Fluorid has become more important substitute. Sulfurid Fluorid is furthermore considered as an alternative to Phosphine, which is more critical in terms of acute toxicity. It is mainly used to fumigate buildings, shipping containers, ships and wood products. Food applications of Sulfuryl Fluoride include the fumigation of dried fruit, tree nuts, dry pulses as well as cereals. It is also used to treat empty storage rooms, silos and grain processing facilities. In the EU residues resulting from applications of Sulfuryl Fluoride are regulated either via an MRL for Sulfuryl Fluoride as well as via an MRL for Fluoride, which is formed when Sulfluryl Fluoride decomposes. Fluoride is thought to be the actual active component as it inhibits the breakdown of fatty acids within the target organisms. |
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Other Aspects
| Compound(s) | No. of Method Finder List/Version/Date of Update | Link | |
|---|---|---|---|
| Analyte protectants | -/(V1)/22.04.2013 | Analytical Observations Report | |
| Short Description: Analyte protectants (APs) are compounds that are added to extracts or standard solutions with the aim to protect the analytes from interactions with active sites within the GC-system. Typically APs are added at concentrations exceeding by far those of the analytes to be protected. Most effective as APs are compounds with multiple hydroxy groups with which they can mask active sites on the surface of the GC-system via hydrogen bonds. | |||
| Compound(s) | No. of Method Finder List/Version/Date of Update | Link | |
|---|---|---|---|
| BNPU (1,3-bis (4-nitrophenyl) urea) | -/(V1)/14.4.2016 | Analytical Observations Report | |
| Short Description: BNPU (a component of Nicarbazin) is often used as a volumetric correction Internal Standard (IS) for acidic pesticides. As IS-losses can lead to severe overestimation of pesticides levels, it is important that there is no IS losses along the procedure. Extensive BNPU-losses are detected when conducting dSPE-cleanup of QuEChERS extracts with GCB (Graphitized Carbon Black). Thus, if Nicarbazin (BNPU) is used as IS, dSPE with GCB sorbent should be avoided and vice versa. dSPE cleanup of QuEChERS extracts does not result in any notable losses but if QuOil extract are subjected to cleanup with PSA BNPU losses are dramatic. No notable losses of BNPU are noticed when 5 % water is added to QuOil extracts prior to cleanup with PSA. | |||
Last modified 06-03-2024, 10:43:24
Published 01-02-2013, 12:21:33
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