Repository of University of Nova Gorica

Show document
A+ | A- | SLO | ENG

Title:Določanje tiametoksama na solati v času karence : diplomsko delo
Authors:Lojpur, Tjaša (Author)
Trebše, Polonca (Mentor) More about this mentor... New window
Files:.pdf Tjasa_Lojpur.pdf (1,35 MB)
 
URL http://repozitorij.ung.si/Dokument.php?id=2872&lang=slv
 
Language:Slovenian
Work type:Bachelor thesis/paper (mb11)
Tipology:2.11 - Undergraduate Thesis
Organization:FZO - Faculty of Environmental Sciences
Abstract:V diplomskem delu sem predstavila rezultate in ugotovitve po izvedbi poskusa na terenu. Podala sem dnevne koncentracije neonikotinoida tiametoksama, enega novejših kontaktnih sistemičnih insekticidov, ki sem ga uporabila na rdeči solati »Red Salad Bowl« (Lactuca sativa), posejani na kmetijski površini. Aktivno snov tiametoksam sem na solato nanesla v obliki fitofarmacevtskega pripravka Actara WG 25, ki se ga uporablja za zatiranje listnih uši in nato spremljala njeno koncentracijo vsak dan v času 7-dnevne karence ter 3. in 7. dan po njej. V ta namen sem uporabila optimizirano metodo za določanje vsebnosti tiametoksama v vzorcih solate. Izvedla sem klasično kemijsko analizo na osnovi tekočinske kromatografije visoke ločljivosti s spektrofotometrijskim detektorjem z diodno matriko (HPLC-DAD). Za obdelavo podatkov sem uporabila osnovne statistične metode (povprečna vrednost, standardni odmik, R²). Z raziskavo sem potrdila, da je v času 7-dnevne karence koncentracija tiametoksama upadla pod mejno vrednost ostankov pesticida (MRL), ki znaša 5 mg/kg in to že 4. dan po nanosu fitofarmacevtskega sredstva, ko je koncentracija njegove aktivne snovi na solati znašala 4,94 mg/kg. Izkoristek ekstrakcije, ki sem jo izvedla v vodi, je znašal 89,71 %, meja detekcije (LOD) pa 0,24 mg/kg. Ugotavljala sem tudi, kako različni meteorološki pojavi, kot so prisotnost sonca, oblačnost in obilnejše deževje vplivajo na hitrost razgradnje tiametoksama na solati. Izkazalo se je, da koncentracija tiametoksama pod vplivom svetlobe upada, ravno tako pa koncentracija znatno upade ob obilnejšem deževju. Za potrebe določanja koncentracije aktivne snovi med samim poskusom sem pripravila tudi umeritveno premico z R²=0,9996 in sicer na način, da sem na HPLC-DAD izvedla meritve vzorcev znanih koncentracij tiametoksama na solati (3,125 mg/kg, 6,25 mg/kg, 12,5 mg/kg, 25 mg/kg in 50 mg/kg).
Keywords:fotorazgradnja, tiametoksam, karenca, solata, hidroliza, diplomske naloge
Year of publishing:2015
Year of performance:2015
Place of performance:Nova Gorica
Publisher:T. Lojpur
Number of pages:IX, 32 str.
Source:Nova Gorica
COBISS_ID:3829499 Link is opened in a new window
UDC:544.5/.6
URN:URN:SI:UNG:REP:CYW0D8JO
Views:2479
Downloads:231
Metadata:XML RDF-CHPDL DC-XML DC-RDF
Categories:Document is not linked to any category.
:
  
Average score:(0 votes)
Your score:Voting is allowed only for logged in users.

Hover the mouse pointer over a document title to show the abstract or click on the title to get all document metadata.

Secondary language

Language:English
Abstract:The diploma thesis presents the results of a field experiment. It analyses decreasing of concentration of neonicotinoid thiamethoxam, newer contact systemic insecticide, which was applied on red lettuce »Red Salad Bowl« (Lactuca sativa), planted on agricultural land. Active substance thiamethoxam was applied on lettuce as a plant protection product Actara 25 WG, which is used to control aphids. Daily concentrations of thiamethoxam were followed during the 7-day withdrawal period and also 3rd and 7th day after the period. For this purpose, an optimized method for the determination of thiamethoxam in samples of lettuce was used, and classical chemical analysis based on high-performance liquid chromatography with diodearray detection (HPLC-DAD) was carried out. Basic statistical analysis (mean value, standard deviation, R²) were used for data processing. The research has shown that during the 7-day withdrawal period the concentration of thiamethoxam fell below maximum residue limit (MRL) of 5 mg/kg. The 4th day after the application of the plant protection product, the concentration of thiamethoxam was 4,94 mg/kg and had already decreased below MRL. The efficiency of the extraction, carried out in water, was 89,71 %, and the limit of detection (LOD) was 0,24 mg/kg. This thesis also discusses the impact of different meteorological conditions such as the presence of sunlight, clouds and rain on the degradation rate of thiamethoxam on lettuce. It seems that the concentration of thiamethoxam decreases under the influence of sunlight and abundant rainfall. For the purpose of determining the concentration of the active substance, a calibration curve with R²=0,9996 was prepared by measuring samples with known concentrations of thiamethoxam on lettuce (3,125 mg/kg, 6,25 mg/kg, 12,5 mg/kg, 25 mg/kg and 50 mg/kg).
Keywords:thiamethoxam, withdrawal period, lettuce, HPLC-DAD, photodegradation, hydrolysis


Back