Delovanje metribuzina na aktivnost nekih enzima u zemljištu

Eeffects of metribuzin on the activity of some enzymes in soil was investigated. Trials were set up in the laboratory on a clay loam soil. Metribuzin was applied at 12.0, 24.0 and 60.0 mg/kg soil rates and soil samples were collected 3, 7, 15, 30 and 45 days after metribuzin treatment for analyses. Alkaline phosphatase, acid phosphatase, dehydrogenase, urease and β-glucosidase were recorded. The results showed that the intensity of metribuzin effects on the activity of enzymes depended on treatment rate, exposure time and enzyme group. Metribuzin had an inhibiting effect on acid phosphatese and dehydrogenase, as well as on alkaline phosphatase in the initial stage before it turned into a stimulating one, while metribuzin stimulated urease and had no effect on β-glucosidase.U radu je ispitivano delovanje metribuzina na aktivnost nekih enzima u zemljištu. Ogled je postavljen u laboratorijskim uslovima na zemljištu tipa černozem. Metribuzin je primenjen u količinama 12,0, 24,0 i 60,0 mg/kg zemljišta, a uzorci za analizu uzimani su 3, 7, 15, 30 i 45 dana posle primene metribuzina. Praćena je aktivnost enzima alkalna i kisela fosfataza, dehidrogenaza, ureaza i β-glukozidaza. Dobijeni rezultati su pokazali da delovanje metribuzina na aktivnost enzima zavisi od primenjene količine, dužine delovanja i vrste enzima. Metribuzin je delovao inhibitorno na kiselu fosfatazu i dehidrogenazu, na alkalnu fosfatazu prvo je delovao inhibitorno, a kasnije stimulativno, na ureazu je delovao stimulativno, dok na β-glukozidazu nije delovao

Rimsulfuron u zemljištu: uticaj na mikrobiološke parametre u različitim tipovima zemljišta

The effects of rimsulfuron a sulfonylurea herbicide on the growth and activity of soil microorganisms under laboratory conditions was investigated in two soils. The application rates were: 0.2, 2.0 and 20.0 mg a.i kg-1 soil. The lowest concentration tested was the label rate (0.2 mg a.i kg-1), and the other two were ten and hundred times higher. No adverse effects on microbiological processes were observed for the label rate. Decrease in microbial biomass carbon, dehydrogenase activity, fungi and bacteria in comparison with untreated control, were found at higher rates. The magnitude of these effects were generally slight and transitory.Na dva tipa zemljišta, u laboratorijskim uslovima, ispitivan je uticaj herbicida rimsulfurona iz grupe sulfonilurea na brojnost i aktivnost zemljišnih mikroorganizama. Rimsulfuron je primenjen u koncentracijama 0,2, 2,0 i 20,0 mg a.s. na kilogram zemljišta. Najmanja ispitivana koncentracija (0,2 mg) odgovarala je količini koja se preporučuje za primenu, a druge dve su deset i sto puta veće od preporučene. Kada je primenjen u preporučenoj količini, rimsulfuron nije imao uticaja na ispitivane mikrobiološke parametre. Smanjenje mikrobiološke biomase ugljenika, dehidrogenazne aktivnosti, brojnosti gljiva i bakterija utvrđene su kod većih koncentracija rimsulfurona. Intenzitet ovih promena je, uglavnom, bio slab i prolaznog karaktera

Poređenje metoda za određivanje ostataka bifentrina u fermentisanim uzorcima žita

Efficiency of three different sample preparation methods for GC/MS determination of bifenthrin residues in wheat (Triticum spelta) samples fermented by Lactobacillus plantarum was tested. The first method was based on a methanol:acetone=1:1 extraction folowed by a purification on columns containing mixture of aluminium oxide and activated charcoal slurry-packed and eluted with dichlormethane, the second was based on methanol:acetone=1:1 extraction folowed by the purification on florisil column and elution by ethil acetate:acetone=4:1, while the third tested method was based on a combination of the first two mentioned methods, thus methanol:acetone=1:1 extraction and clean-up throught columns filled with a mixture of aluminum oxide and activated charcoal slurrypacked and eluted with ethil acetate:acetone=4:1. The second method was the most effective for obtaining satisfactory recoveries for bifenthrin in a range of 79-83% for four fortification levels, with good reproducibility i.e. RSD% in a range of 2.2-7.4%. The chosen method was further optimized by assessing the optimum volume of elution solvent used during the clean-up procedures. The highest recovery of 82.1% was obtained after elution with 25 ml of solvent. Overall, two-step extraction with 25 ml of methanol:acetone=1:1 solvent mix for 30 min, followed by clean-up procedure through a glass column with florisil coupled with elution with 25 ml of ethyl acetate: acetone=4:1, allows simple, efficient and reliable GC/MS detection of bifenthrin residues from wheat grain fermented by L. plantarum.Testirane su efikasnosti tri različite metode pripreme uzoraka za određivanje ostataka bifentrina u uzorcima pšenice (Triticum spelta) fermentisane pomoću Lactobacillus plantarum. Prva metoda zasnivala se na metanolsko-acetonskoj (1:1) ekstrakciji i prečišćavanju kroz kolonu punjenu smešom aluminijum-oksida i aktivnog uglja u kombinaciji sa dihlormetanom kao eluentom, druga se zasnivala na metanolsko-acetonskoj (1:1) ekstrakciji i prečišćavanju kroz kolonu punjenu florisilom u kombinaciji sa smešom etil-acetata i acetona (4:1) kao eluentom, dok se treća zasnivala na kombinaciji prve dve, tj. metanolsko-acetonskoj (1:1) ekstrakciji i prečišćavanju kroz kolonu punjenu smešom aluminijum-oksida i aktivnog uglja u kombinaciji sa smešom etil-acetata i acetona (4:1) kao eluentom. Pokazalo se da je druga testirana metoda najefikasnija, pri čemu su dobijeni prinosi bifentrina u opsegu 79-83% za četiri koncentraciona nivoa obogaćivanja, sa RSD% u opsegu 2,2-7,4%. Odabrana metoda je dodatno optimizovana variranjem različitih zapremina korišćenog eluenta. Najveći prinos metode postignut je pri zapremini eluenta od 25 ml. Predložena metoda, bazirana na 30-minutnoj ekstrakciji sa 25 ml smeše metanol:aceton=1:1, prečišćavanju na florisilskoj koloni i eluiranju sa 25 ml smeše etil-acetat:aceton=4:1, pokazala se kao efikasna, jednostavna i pouzdana metoda za određivanje ostataka bifentrina u fermentisanom žitnom supstratu

Određivanje atrazina, acetohlora, klomazona, pendimetalina i oksifluorfena u zemljištu metodom mikroekstrakcije u čvrstoj fazi

A solid phase microextraction (SPME) method for simultaneous determination of atrazine, acetochlor, clomazone, pendimethalin and oxyfluorfen in soil samples was developed. The method is based on a combination of conventional liquid-solid procedure and a following SPME determination of the selected pesticides. Initially, various microextraction conditions, such as the fibre type, desorption temperature and time, extraction time and NaCl content, were investigated and optimized. Then, extraction efficiencies of several solvents (water, hexane, acetonitrile, acetone and methanol) and the optimum number of extraction steps within the sample preparation step were optimized. According to the results obtained in these two sets of experiments, two successive extractions with methanol as the extraction solvent were the optimal sample preparation procedure, while the following conditions were found to be most efficient for SPME measurements: 100 μm PDMS fibre, desorption for 7 min at 2700C, 30 min extraction time and 5% NaCl content (w/v). Detection and quantification were done by gas chromatography-mass spectrometry (GC/MS). Relative standard deviation (RSD) values for multiple analysis of soil samples fortified at 30 μg/kg of each pesticide were below 19%. Limits of detection (LOD) for all the compounds studied were less than 2 μg/kg.Za istovremeno određivanje atrazina, acetohlora, klomazona, pendimetalina i oksifluorfena u zemljištu ustanovljena je metoda mikroekstrakcije u čvrstoj fazi (SPME). Metoda je zasnovana na kombinaciji klasične tečno-čvrste pripreme uzorka i SPME određivanja. Izvršena je optimizacija najvažnijih mikroekstrakcionih parametara, kao što su izbor ekstrakcionog vlakna, desorpciona temperatura i vreme, ekstrakciono vreme i sadržaj natrijumhlorida (NaCl). Ispitivani su, takođe, ekstrakciona efikasnost različitih rastvarača (voda, heksan, acetonitril, aceton i metanol), kao i optimalan broj ekstrakcionih koraka u toku pripreme uzoraka zemljišta. Na osnovu rezultata dobijenih iz ova dva seta eksperimenata izabrani su sledeći radni uslovi: dve sukcesivne ekstrakcije sa metanolom kao ekstrakcionim rastvaračem u stupnju pripreme uzorka, dok su za mikroekstrakcione uslove uzeti: 100 μm PDMS vlakno, desorpcija u trajanju od 7 min na 270ºC, ekstrakciono vreme – 30 min, uz dodatak NaCl (5%, w/v). Detekcija i kvantifikacija analita je vršena gasno-masenim spektrometrom (GC/MS). Vrednosti relativnih standardnih devijacija (RSDs) višestruko ponovljenog merenja uzorka obogaćenog do 30 μg/kg svakog pesticida su ispod 19%. Granice detekcije (LODs) za sve pesticide uključene u ispitivanje su ispod 2 μg/kg

Uticaj sadržaja organske materije i gline u zemljištu na adsorpciju pesticida

The effect of organic matter and clay content on the adsorption of atrazine, acetochlor, clomazone, pendimethalin and oxyfluorfen in soil samples was studied. In order to determine whether and to what degree different soil properties affect the process of determination of selected pesticides, three soils with different clay and organic matter contents were used. An optimized liquid-solid extraction procedure followed by SPME measurement was applied to analyse the selected pesticides in soil samples. Detection and quantification were done by gas chromatography-mass spectrometry (GC/MS). Relative standard deviation (RSD) values for multiple analyses of soil samples fortified at 30 μg/kg of each pesticide were below 19%. Limits of detection (LODs) for all compounds studied were less than 2 μg/ kg. The results indicate that soils with different physico-chemical properties have different effects on the adsorption of most pesticides, especially at higher concentration levels.Proučavan je uticaj sadržaja organske materije i gline u uzorcima zemljišta na procese adsorpcije atrazina, acetohlora, klomazona, pendimetalina i oksifluorfena. U cilju utvrđivanja da li i u kojoj meri različite zemljišne karakteristike utiču na adsorpciju proučavanih pesticida, a time i na njihovo određivanje, izabrana su tri zemljišta sa različitim sadržajem organske materije i gline. Za određivanje pomenutih pesticide u uzorcima zemljišta korišćena je optimizovana tečno-čvrsta ekstrakciona procedura u kombinaciji sa metodom mikroekstrakcije u čvrstoj fazi (SPME). Detekcija i kvantifikacija analita je vršena gasno-masenim spektrometrom (GC/MS). Vrednosti relativnih standardnih devijacija (RSDs) višestruko ponovljenog merenja uzorka obogaćenog do 30 μg/kg svakog pesticida su ispod 19%. Granice detekcije (LODs) za sve pesticide i zemljišta uključena u ispitivanje su bila ispod 2 μg/kg. Rezultati ukazuju da zemljišta različitih fizičko-hemijskih karakteristika imaju različit uticaj na sorpciju za većinu proučavanih jedinjenja, što je naročito izraženo kod većih koncentracija

Metoda tečno-čvrste ekstrakcije za određivanje pesticida u uzorcima zemljišta

A multiresidue method for simultaneous determination of four pesticides (diazinon, acetochlor, aldrine and carbofuran) belonging to different pesticide groups, extracted from soil samples, is described. The method presented is based on liquid-solid extraction (LSE) and determination of pesticides, i.e. the pesticides were extracted by methanol- acetone mixture, purified on florisil column and eluted by ethyl acetate-acetone mixture. Optimization of the main parameters affecting the LSE procedure, such as the choice of purification sorbent, as well as the elution solvent and its volume, were investigated in details and optimized. Also, validation of the proposed method was done. Gas chromatography-mass spectrometry (GC-MS) was used for detection and quantification of the pesticides studied. Relative standard deviation (RSD) and recovery values for multiple analysis of soil samples fortified with 30 μg/kg of each pesticide were below 8% and higher than 89%, respectively. Limits of detection (LOD) for all the compounds studied were less than 4 μg/kg.U radu je prikazana metoda tečno-čvrste ekstrakcije (LSE) za istovremeno određivanje pesticida (diazinon, acetohlor, aldrin i karbofuran) u zemljištu, koji na osnovu svoje strukture pripadaju različitim hemijskim grupama. Metoda se zasniva na metanolsko-acetonskoj ekstrakciji uzoraka zemljišta, koja je praćena prečišćavanjem na florisilu i eluiranju sa smešom etil-acetata i acetona. Izvršena je optimizacija glavnih eksperimentalnih parametara koji mogu da utiču na efikasnost LSE metode, kao što su izbor sorbenta za prečišćavanje zemljišnog ekstrakta pesticida, izbor adekvatnog eluenta i njegove optimalne zapremine. Takođe, izvršena je i validacija optimizovane metode. Detekcija i kvantifikacija ispitivanih pesticida su izvršeni metodom gasno-masene spektrometrije (GC-MS). Vrednosti relativnih standardnih devijacija (RSD) i prinosa određivanja pesticida u uzorcima zemljišta obogaćenim do koncentracija od 30 μg/kg svakog jedinjenja su ispod 8%, odnosno iznad 89%, respektivno, dok su granice detekcije (LOD) niže od 4 μg/kg

Određivanje mikrobiološke aktivnosti i biomase u različitim zemljištima nakon primene nikosulfurona

The effects of the herbicide nicosulfuron on the abundance of cellulolytic and proteolytic microorganisms, activity of β-glucosidase and protease enzymes, and microbial phosphorus biomass were examined. A laboratory bioassay was set up on two types of agricultural soils differing in physicochemical properties. The following concentrations were tested: 0.3, 0.6, 3.0 and 30.0 mg a.i./kg of soil. Samples were collected 3, 7, 14, 30 and 45 days after treatment with nicosulfuron. The results showed that nicosulfuron significantly reduced the abundance of cellulolytic microorganisms in both soils, as well as microbial biomass phosphorus in sandy loam soil. The herbicide was found to stimulate β-glucosidase and protease activity in both types of soil and microbial biomass phosphorus in loamy soil. Proteolytic microorganisms remained unaffected by nicosulfuron.Ispitivan je uticaj herbicida nikosulfurona na brojnost celulolitskih i proteolitskih mikroorganizama, aktivnost enzima β-glukozidaze i proteaze i mikrobiološku biomasu fosfora. Ogled je postavljen u laboratorijskim uslovima na dva poljoprivredna zemljišta koja se razlikuju po svojim fizičko-hemijskim karakteristikama. Primenjene su koncentracije od 0,3, 0,6, 3,0 i 30,0 mg a.s/kg zemljišta. Uzorci za analizu uzeti su 3, 7, 14, 30 i 45 dana nakon primene nikosulfurona. Dobijeni rezultati su pokazali da je nikosulfuron značajno smanjio broj celulolizatora kod oba tipa zemljišta, kao i vrednost mikrobiološke biomase fosfora u peskuši. Stimulativno delovanje ovog herbicida zabeleženo je kod enzima β-glukozidaze i proteaze kod oba tipa zemljišta kao i kod mikrobiološke biomase fosfora u ilovači. Na brojnost proteolitičkih mikroorganizama nikosulfuron nije ispoljio nikakav uticaj