Brown algal phlorotannins: Improving and applying chemical methods

Phlorotannins are the least studied group of tannins and are found only in brown algae. Hitherto the roles of phlorotannins, e.g. in plant-herbivore interactions, have been studied by quantifying the total contents of the soluble phlorotannins with a variety of methods. Little attention has been given to either quantitative variation in cell-wall-bound and exuded phlorotannins or to qualitative variation in individual compounds. A quantification procedure was developed to measure the amount of cell-wall-bound phlorotannins. The quantification of soluble phlorotannins was adjusted for both large- and small-scale samples and used to estimate the amounts of exuded phlorotannins using bladder wrack (Fucus vesiculosus) as a model species. In addition, separation of individual soluble phlorotannins to produce a phlorotannin profile from the phenolic crude extract was achieved by high-performance liquid chromatography (HPLC). Along with these methodological studies, attention was focused on the factors in the procedure which generated variation in the yield of phlorotannins. The objective was to enhance the efficiency of the sample preparation procedure. To resolve the problem of rapid oxidation of phlorotannins in HPLC analyses, ascorbic acid was added to the extractant. The widely used colourimetric method was found to produce a variation in the yield that was dependent upon the pH and concentration of the sample. Using these developed, adjusted and modified methods, the phenotypic plasticity of phlorotannins was studied with respect to nutrient availability and herbivory. An increase in nutrients decreased the total amount of soluble phlorotannins but did not affect the cell-wall-bound phlorotannins, the exudation of phlorotannins or the phlorotannin profile achieved with HPLC. The presence of the snail Thedoxus fluviatilis on the thallus induced production of soluble phlorotannins, and grazing by the herbivorous isopod Idotea baltica increased the exudation of phlorotannins. To study whether the among-population variations in phlorotannin contents arise from the genetic divergence or from the plastic response of algae, or both, algae from separate populations were reared in a common garden. Genetic variation among local populations was found in both the phlorotannin profile and the content of total phlorotannins. Phlorotannins were also genetically variable within populations. This suggests that local algal populations have diverged in their contents of phlorotannins, and that they may respond to natural selection and evolve both quantitatively and qualitatively.Siirretty Doriast

Report of an interlaboratory comparison organised by the European Union Reference Laboratory for Food Contact Materials; ILC01 2010 - Photoinitiators in solvent and in paperboard

This report presents the results of the ILC of the EURL-FCM which focused on the screening for photoinitiators (PI) content in paperboard as well as in a solvent. The test materials used were two types of paperboard supplied by the industry, containing benzophenone (BP) and 4-methylbenzophenone (4MBP) and mixtures of five PIs in a solvent (acetonitrile) prepared in-house. The general aim of the exercise was to assess the proficiency of the official control laboratories and consequently the participants were free to use an analytical method of their choice. There were 36 participants to whom samples were dispatched (26 NRLs + 10 official national control laboratories from Germany and Spain) 32 of which submitted results. The homogeneity and stability studies were performed by the EURL-FCM laboratory. The assigned values were obtained after applying robust statistics to the results of the participants. Participants were invited to report four replicates measurements. This was done by most of the participants. Laboratory results were rated with z and z¿ scores in accordance with ISO 13528 [1] Standard deviations for proficiency assessment (also called target standard deviations) were set based on Horwitz equation for substances in the solvent. For the PI paperboard the target standard deviation was set by the organizers to 15% in order to fulfil the required criteria for sufficient homogeneity of the sample within the lots. As a conclusion of the ILC exercise on the quantification of photoinitiators in the paperboard and the solvent, this ILC showed that: 1) The participation in the ILC was satisfactory regarding the number of the participating labs. Thirty-two laboratories submitted their results. From the EURL-NRL network 22 laboratories out of 25 reported results. 3 NRLs laboratories did not send any results. 2) For the network of NRL-FCM the outcome from the participation could be regarded as satisfactory as there are about 84% satisfactory results (262 out of 312) and only 3 NRLs did not participated out of 25JRC.I.2-Chemical assessment and testin

Laboratorioiden välinen vertailumittaus 02/2016 - Trihalometaanit vedestä

Proftest SYKE järjesti helmikuussa 2016 vertailumittauksen trihalometaanien määrityksistä uima-allas- ja talousvesistä. Vertailumittauksessa oli yhteensä 5 osallistujaa. Koko tulosaineistossa oli z-arvoja käytettäessä hyväksyttäviä tuloksia 70 %, kun vertailuarvosta sallittiin synteettisessä näytteessä 15–25 %, juomavesinäytteessä 25 % ja uima-allasvesissä 25–40 %:n poikkeama. Näytteiden THM-pitoisuuksien vertailuarvoina käytettiin laskennallisia pitoisuuksia. Pätevyyden arvoinnissa käytettiin z-arvoa, lisäksi laskettiin En- ja D%-arvot. Kiitos osallistujille

Laboratorioiden välinen vertailumittaus 02/2018 - Trihalometaanit vedestä

Proftest SYKE järjesti helmikuussa 2018 vertailumittauksen laboratorioille, jotka määrittävät trihalometaaneja (THM) uima-allas- ja talousvedestä. Vertailumittaukseen osallistui yhteensä 6 laboratoriota. Näytteiden THM-pitoisuuksien vertailuarvoina käytettiin teoreettista (laskennallista) pitoisuutta tai osallistujien tulosten keskiarvoa tai mediaania. Tulosaineistossa oli z-arvoja käytettäessä hyväksyttäviä tuloksia 99 %, kun tulosten sallittiin vaihdella 15–30 % vertailuarvosta. Lisäksi joissakin tapauksissa tulosten arvioinnissa käytettiin En-arvoja. Kiitos osallistujille

Interlaboratory Proficiency Test 09/2015 - PCB compounds in soil

Proftest SYKE carried out the proficiency test (PT) for analysis of PCB compounds in soil in November-December 2015 (PCB 09/2015). Two types of samples were delivered to the participants, synthetic and soil samples. In total, 8 laboratories participated in the PT. The evaluation of the performance was based on the z scores, which were calculated using the standard deviation for proficiency assessment at 95 % confidence level. In this proficiency test 79 % of the data was regarded to be satisfactory when the standard deviation of 20 to 30 % from the assigned value was accepted. For the synthetic sample the calculated concentration and for the soil sample the mean of the results reported by the participants was chosen to be the assigned value. The uncertainty for the assigned value was estimated at the 95 % confidence interval and for calculated assigned values it was 0.5–1.2 %, for assigned values based on the mean it varied from 6.8 to 21.3 %

Laboratorioiden välinen pätevyyskoe 12/2018 - PAH- ja PCB-yhdisteet sekä öljyhiilivedyt maasta

Proftest SYKE järjesti marraskuussa 2018 pätevyyskokeen laboratorioille, jotka määrittävät PAH- ja PCB-yhdisteitä sekä öljyhiilivetyjä maasta (ORG 12/2018). Osallistujille toimitettiin synteettiset näytteet jokaisesta yhdisteryhmästä sekä yksi saastunut maanäyte. Pätevyyskokeeseen osallistui yhteensä 9 laboratoriota. Testisuureen vertailuarvona käytettiin laskennallista pitoisuutta, osallistujien tulosten mediaania tai keskiarvoa. Osallistujien pätevyyden arviointi tehtiin z- ja En-arvojen avulla. Koko tulosaineistosta hyväksyttäviä tuloksia oli z-arvojen perusteella 69 %, kun vertailuarvosta sallittiin 15–30 %:n poikkeama. Tuloksista, jotka arvioitiin En-arvoilla, oli hyväksyttäviä 66 %. Kiitos pätevyyskokeen osallistujille

Interlaboratory Proficiency Test 13/2017 - Oil hydrocarbons in water and soil

Proftest SYKE carried out the proficiency test (PT) for analysis of oil hydrocarbons in water and soil in November 2017. Three types of samples were delivered to the participants: synthetic sample, surface water and soil samples. In total, 16 participants joined in the PT. In this proficiency test 76 % of the results were satisfactory when deviation of 20–40 % from the assigned value was accepted. Basically, either the calculated concentration, the robust mean, or the median of the results reported by the participants was used as the assigned value for measurands. The evaluation of the performance of the participants was carried out using the z scores. Warm thanks to all the participants of this proficiency test

Interlaboratory Proficiency Test 14/2017 - Leaching behavior test for solid waste material : Up-flow percolation test

Proftest SYKE carried out the proficiency test in cooperation with the KVVY Tutkimus Oy for the laboratories conducting leaching tests for solid waste samples at the turn of the year 2017-2018. The results of the up-flow percolation test (EN 14405:2017) for fly ash samples were compared and evaluated. In total, 8 participants joined in the proficiency test. Either the mean or the median of the results reported by the participants was used as the assigned value for the measurands. The overall performance evaluation was done with the En scores and 64 % of the all the evaluated results were satisfactory. The performance evaluation for the results for pH as well as for the cumulative values L/S 2 and L/S 10 of the measurands was done also with the z scores. In the evaluation based on z scores, 85 % of the results were satisfactory, when deviation was set to 0.5 pH units, to 20 % for SO4 and to 50 % for other measurands. For these same results, 78 % of the results were satisfactory when evaluated with the En scores. Warm thanks to all the participants

Interlaboratory Proficiency Test 04/2020. Leaching behavior test for waste material : Two stage batch leaching test

Proftest SYKE carried out the proficiency test in cooperation with KVVY Tutkimus Oy for the laboratories conducting leaching tests for solid waste material in May-June 2020. The results of the two stage batch leaching test (EN 12457-3) for samples of treated slag from waste combustion were compared and evaluated. The tested measurands were metals (As, Ba, Cd, Cr, Cu, Hg, Mo, Ni, Pb, Sb, Se, V, Zn), Cl-, F-, SO42-, DOC, pH, conductivity, and TDS. In total, 13 participants joined in the proficiency test. In this proficiency test either the robust mean or the median of the results reported by the participants was used as the assigned value. The results were evaluated both with z and En scores. When deviation of 10–35 % or 0.3-0.4 pH units was accepted from the assigned value, 85 % of the results evaluated with z scores were satisfactory. Of the results evaluated with En scores, 80 % were satisfactory. Warm thanks to all the participants of this proficiency test

Interlaboratory Proficiency Test 13/2018 - Leaching behavior test for solid waste material : One stage batch leaching test

Proftest SYKE carried out the proficiency test in cooperation with KVVY Tutkimus Oy for the laboratories conducting leaching tests for solid waste material in November-December 2018. The results of the one stage batch leaching test (EN 12457-2) for foundry sand samples were compared and evaluated. The tested measurands were metals (As, Ba, Cd, Cr, Cu, Hg, Mo, Ni, Pb, Sb, Se, V, Zn), Cl-, SO4 2-, F-, DOC, pH, and conductivity. In total, 10 participants joined in the proficiency test. In this PT for all the evaluated measurands the median of the results reported by the participants was used as the assigned value. The measurands Ba, conductivity, DOC, Ni, pH, SO4, and Zn were evaluated with z scores and of those results 92 % were satisfactory, when deviation of 0.3 pH units and 20–30 % for other measurands was accepted from the assigned value. Further, measurands As, Cr, Cu, and V were evaluated with En scores and 76 % of the results were satisfactory. Warm thanks to all participants in this proficiency test