Kögel, Tanja

Löschner, Katrin

Sanden, Monica

Sele, Veronika

Solli, Berit

Valdersnes, Stig

Online Research Database In Technology

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Downloaded from orbit.dtu.dk on: Jul 07, 2018Towards a future screening method  for nanoparticles in seafood – For surveillanceand risk assessment of food safetyValdersnes, Stig; Löschner, Katrin; Solli, Berit; Kögel, Tanja; Sanden, Monica; Sele, VeronikaPublication date:2018Document VersionPublisher's PDF, also known as Version of recordLink back to DTU OrbitCitation (APA):Valdersnes, S., Löschner, K., Solli, B., Kögel, T., Sanden, M., & Sele, V. (2018). Towards a future screeningmethod  for nanoparticles in seafood – For surveillance and risk assessment of food safety. Poster sessionpresented at 9th Nordic Conference on Plasma Spectrochemistry, Loen, Norway.www.hi.noTowards a future screening methodfor nanoparticles in seafood–For surveillance and risk assessment of food safetyNeed for analytical method for determination of NPs in marine samplesEngineered nanoparticles (NPs) are used worldwide, due to their unique, useful characteristics. NPs have been shown to be taken up by organisms and intocells, where they influence these organisms negatively, e.g. by increasing oxidative stress. NPs can also be produced unintentionally, e.g. through grindingprocesses related to mining. Norway is one of very few countries using the sea for dumping mining waste, and recently, mining companies have received newpermissions to deposit large amounts of mining waste in the Repparfjord and Førdefjord. This emphasizes the need for an analytical platform applicable forsurveillance and screening of NPs of unknown compositions in seafood organisms and indicators of environmental status.Stig Valdersnes1, Katrin Loeschner2, Berit Solli1, Tanja Kögel1, Monica Sanden1 and Veronika Sele11) Institute of Marine Research (IMR), P.O box 1870 Nordnes, NO-5817 Bergen.2) Technical University of Denmark (DTU), Kemitorvet 201, 2800 Kgs. Lyngby, DenmarkDetermination of particle size by sp-ICP-MSParticle size plays a role in the toxicity of elements or metals. Hence, this new analyticaldimension of size needs to be added to the already established total and species specificdetermination of metals and elements to aid in the future risk assessments of foodsafety. Single particle inductively coupled plasma mass spectrometry (sp-ICP-MS) hasbeen shown to be a powerful analytical technique for the determination of the sizedistribution of NPs [1]. For the determination of nanoparticles, however, the sampleneeds to be in suspension, and decomposition of the matrix by acids, bases andenzymes is necessary to extract NPs into solution [2, 3].To evaluate the effect of the extraction procedure on the NPs, different types of marinesamples, including mussel tissue (blue mussel), oyster tissue (Oyster tissue, CRM, NIST1566b), fish muscle tissue and fish feed were extracted with various extractionprocedures. The samples analysed were spiked with reference material (30nm and 60nmAu), and extracted with water (1), acidic digestion (2), basic digestion (3) (TMAH), and byenzymatic digestion (protamex and proteinase K, (4, 5)). Spiked and non-spiked sampleswere then analysed by sp-ICP-MS, with detection of 197Au. Selected samples were alsoanalysed for 56Fe and 66Zn.Experimental outlineResults and discussionRF power 1550Nebulizing gas 1.05Nebulizer MicromistNebulizer pump 0.1Torch 1.5 mmTubing ID 1.02 mmIntegration time 0.1 msec (peak integration mode)Isotopes monitored 197Au, 56Fe, 66ZnAnalysis time 60 secProbe rinse 60 secReference material Au (100ppt, 200ppt)Ion standards Au, Zn, Fe (1ppb, 10ppb, 100ppb)Table 1. Instrumental settings for sp-ICP-MS (7900, Agilent Technologies) and autosampler (Agilent Technologies) Figure 1. Sample digested with TMAHand enzyme (protamex). The TMAHextract was clearer compared to theenzymatic digest.[1] Laborda, F., Bolea, E. & Jiménez-Lamana, J., 2014. Single particle inductively coupled plasma mass spectrometry: a powerful tool for nanoanalysis. Analytical chemistry, 86(5), pp.2270–2278[2] Loeschner, K. et al., 2013. Detection and characterization of silver nanoparticles in chicken meat by asymmetric flow field flow fractionation with detection by conventional or single particle ICP-MS. Analytical and bioanalytical chemistry, 405(25), pp.8185–8195.[3] Kollander, B. et al., 2017. Detection of lead nanoparticles in game meat by single particle ICP-MS following use of lead-containing bullets. Analytical and bioanalytical chemistry, 409(7), pp.1877–1885.The aim of this project is to develop a generic analytical screening method for metal containing nanoparticles (NPs) in seafood using single particle inductively coupled plasma mass spectrometry (sp-ICP-MS), and here the preliminary results from the project are presented.Table 2. Measured and certified/reported concentration (mg/kg) ofiron (56Fe) and zinc (66Zn) in Oyster tissue (CRM 1566b) and in fishfeed when extracted with acid digestion.Figure 3. A mixture of 30 nm and 60 nm Au NPs spiked into waterextracts of feed, mineral mix and urine.Further work needs to be conducted to verify that thematrix effects also applies to NPs analysis by sp-ICP-MS.Figure 4. Particle size distribution of 60nm NPs spiked in Oystertissue (SRM-1566b) and extracted using protocol 1-5.Acid digestion completely digests the NPs, whereaswater extraction, enzymatic and TMAH digestion results insignals for NPs in the 60 nm region. Extraction with water andprotamex gives a lower signal in the low nm particle sizeregion (10-40 nm) compared to the other protocols.56Fe 66ZnMeasured concentration (mg/kg)Certified/reported concentration (mg/kg)Measured concentration (mg/kg)Certified/reportedconcentration (mg/kg)Oyster tissue 233 205.8 ± 6.8 1424 1424 ± 46 Fish feed 270 220 ± 34 137 140 ± 3Conclusion and future work• The preliminary data indicate that milder extractionconditions such as enzymes and water could be used forAu NP extraction in marine samples. While TMAHdissolves the samples more completely.• The aim for future work is to establish a screeningmethod for NPs in seafood using sp-ICP-MS.• Furture work will focus on determining titanium (Ti) andcopper (Cu) as these are the main elements of interestregarding mining activities in Norway.• Also NPs of other elements, e.g. zinc (Zn), iron (Fe),mercury (Hg), selenium (Se), are of interest to study inmarine samples.• Complementary techniques, e.g. transmission electronmicroscopy (TEM) and asymmetric flow field flowfractionation (AF4), will be require to obtain morespecific information on the nanoparticles.01020304050607080901000 4 8 12 16 20 24 28 32 36 40 44 48 52 56 60 64 68 72 76 80 84 88 92 96 100Abundance, %Particle size, nmMatrix effectsAu197, 500 ppt feed Au197, 500 ppt mineral mix Au197, 500 ppt urine3Figure 2. Particle size distribution measured for NP solutions of60 nm Au (A) and 30 nm Au (B) with concentrations from 50 pptto 500 ppt.A slight shift in size is seen for the most concentratedsolution of 60 nm NPs . This is not seen for 30 nm NPssolutions.Transport/nebulization efficiency (TE/NE) is one of the mostimportant parameters in sp-ICP-MS.TE/NE was determined using (1) the particle size, (2) theparticle concentration and by (3) manual uptake. Approach(3) gave the highest value of the TE/NE; varying from 7-11 %(n = 4) when measured on a daily basis. The TE/NE measuredby (1) and (2) gave an estimate of around 5 and 4 %,respectively.Only minor differences were seen in the results forparticle size distribution when applying the different TE/NEdetermination approaches.Transport/nebulization efficiency1Total concentration of other elements such as Fe and Zn inoyster tissue and fish feed could also be determinedsimultaneously with particle size in sp-ICP-MS-mode.NPs of Fe and Zn were not detected in the acid digest or in thewater extracts of oyster tissue and fish feed.0204060801000 6 12 18 24 30 36 42 48 54 60 66 72 78 84 90 96Abundance, %Effect of particle numberAu197, 50ppt, N=272 particlesAu197, 100 ppt, N=626 particlesAu197, 250 ppt, N= 1431 particlesAu197, 500 ppt, N=3045 particles20204060801000 6 12 18 24 30 36 42 48 54 60 66 72 78 84 90 96Abundance, %Particle size, nmAu197, 50 ppt, N=1087 particlesAu197, 100 ppt, N=1982 particlesAu197, 250 ppt, N=5214 particlesAu197, 500 ppt, N=10671 particlesAB

Towards a future screening method for nanoparticles in seafood – For surveillance and risk assessment of food safety

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Towards a future screening method for nanoparticles in seafood – For surveillance and risk assessment of food safety

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