Utjecaj organskih i mineralnih sastojaka tla na sorpcijsko ponašanje klorfenolnih i triazinskih mikrozagađivala

This article compares the sorption behaviour of 2,4,6-trichlorophenol, 2,3,4,6-tetrachlorophenol, pentachlorophenol, chlorotriazine atrazine, methylthiotriazine ametryn, methoxytriazine atratone, hydroxyatrazine, and didelakylated atrazine in a topsoil and an aquifer sediment before and after removal of sorbent organic matter and in humic acid. Freundlich isotherm coeffi cients Kf and 1/n and free energy change (∆G°) were calculated for all compounds in all sorbents. According to sorbent pH values, chlorophenolate anions and uncharged triazine species dominated in all sorption experiments with topsoil and aquifer sediment. In experiments with humic acid, chlorophenols, atrazine, and didealkylated atrazine existed almost completely as neutral species, whereas protonated species dominated for hydroxyatrazine, atratone, and ametryn. In addition to a hydrophobic partition, sorption of all compounds in native soil and sediment sorbents includes specifi c, more polar interactions, which greatly depend on sorbate acidity/ basicity, specifi c properties of the sorbent organic matter and of mineral surface, as well as on the system pH. A signifi cantly greater sorption intensity of all compounds in “organic-free” than in the native aquifer sediment confi rmed the importance and possible dominance of mineral surface in the sorption process. Sorption intensity of chlorophenol and triazine compounds in humic acid was closely related to compound hydrophobicity. Greater sorption of almost completely protonated hydroxyatrazine than of the more hydropohobic but uncharged atrazine indicated different humic acid reaction sites for two compounds and consequently different sorption mechanisms.Uspoređena je sorpcija 2,4,6-triklorfenola, 2,3,4,6-tetraklorfenola i pentaklorfenola te različito supstituiranih triazinskih spojeva - klortriazina atrazina, metiltiotriazina ametrina, metoksitriazina atratona i razgradnih produkata atrazina hidroksiatrazina i didealkiliranog atrazina – u površinskom tlu i sedimentu vodonosnika prije i nakon uklanjanja organske tvari te u huminskoj kiselini. Izračunani su koefi cijenti Freundlichove izoterme Kf i 1/n te izmjena slobodne energije (∆G°) za sve spojeve i sorbense. U skladu s pH-vrijednostima sorbensa u svim su sorpcijskim pokusima s nativnim tlom i sedimentom prevladavali klorfenolatni anioni i neutralni triazinski spojevi. U pokusima s huminskom kiselinom klorfenoli, atrazin i didealkilirani atrazin postojali su kao neutralne vrste, dok su hidroksiatrazin, atraton i ametrin bili većim dijelom protonirani. Sorpcija svih spojeva u prirodnom tlu i sedimentu uključuje uz hidrofobnu particiju i specifi čne polarnije interakcije ovisne o kiselosti/bazičnosti sorbata, specifi čnim svojstvima organske tvari i mineralne površine sorbensa te o pH-vrijednosti sustava. Intenzitet sorpcije svih spojeva u sedimentu iz kojeg je uklonjena organska tvar bio je značajno veći od sorpcije u prirodnom sedimentu, što potvrđuje važnost i moguću dominantnu ulogu mineralne površine u sorpcijskom procesu. Intenzitet sorpcije klorfenola te klortriazina, metiltiotriazina i metoksitriazina u huminskoj kiselini korelirao je s hidrofobnosti spojeva. Veća sorpcija gotovo potpuno protoniranog hidroksiatrazina od hidrofobnijeg, ali neutralnog atrazina upućuje na različita reakcijska mjesta za ova dva spoja, a time i na različite mehanizme sorpcije u huminskoj kiselini

Trače Enrichment of Polychlorinated Biphenyls in Soil: Efficiency of Sonicated Liquid-solid Extraction with Acetone/n-Hexane Mixture from Different Soil Types

The efficiency and reproducibility of an analytical procedure for trace determination of polychlorinated biphenyls (PCBs) in soil/sediment samples were evaluated by analyses of soils differing in their sorption-controlling properties. PCBs were accumulated from soil by sonicated multiple extraction with a 1:1 acetone/n-hexane mixture. The extracts, purified by treatment with copper powder, mercury, and sulphuric acid were analyzed by gas chromatography. The extraction efficiency from a soil spiked with 4-430 μg kg-1 of Aroclor 1242/Aroclor 1260 mixture depended on the initial PCB mass fraction. The matrix effect was evaluated by the analysis of PCBs added to five European reference soils differing in organic matter content, grain size distribution, mineral composition, pH values, and iron and aluminium oxides content. In four of these soils, a linear correlation was found between the slopes of calibration lines for the determination of PCBs and soil organic matter content. An exception was the most acidic soil with the highest, but poorly humified, organic matter. The linear regression of calibration line slopes and the content of soil fine silt particles indicated a positive, but not statistically significant, correlation

Dinamika disipacije terbutilazina u tlu tijekom vegetacije kukuruza

Ever since terbuthylazine (TBA) replaced atrazine in herbicide crop treatment, its much greater persistence has raised considerable environmental concern. The aim of our field experiment was to establish the dissipation dynamics of TBA and its degradation product desethylterbuthylazine (DET) in soil over five months of maize growth. We applied TBA as part of pre-emergent treatment in the regular and double-the-regular amounts. Soil samples were collected periodically at the following depths: 0-10 cm, 10-20 cm, 20-30 cm, and 30-50 cm. For TBA and DET soil residue analysis we used microwave-assisted extraction with methanol, followed by HPLC-UV/DAD. Regardless of the application rate, more than 80 % of the applied TBA dissipated from the first 50 cm of soil in the two months after herbicide application and 120 mm of rainfall. Three months later (at maize harvest), less than 4 % of total TBA remained in the soil, mostly in the top 20 cm rich with organic carbon on which TBA is likelier to adsorb. The loss of TBA from soil coincided with the rise in DET, especially the top soil layers, during the periods of low rainfall and highest soil temperatures. This points to biodegradation as the main route of TBA dissipation in humic soils. The applied amount had no significant effect on TBA dissipation in the top (humic) layers, but in the layers with less than 1 % of organic carbon, it was higher when the double-the-regular dose was applied.Terensko istraživanje dinamike disipacije herbicida terbutilazina (TBA) i njegova razgradnog produkta deetilterbutilazina (DET) u tlu provodilo se tijekom pet mjeseci proizvodnje kukuruza. Terbutilazin je primijenjen kao zemljišni herbicid u propisanoj dozi i u dvostruko višoj dozi od propisane. Uzorci tla periodično su skupljani pri dubinama 0-10 cm, 10-20 cm, 20-30 cm i 30-50 cm. Ostaci herbicida u tlu ekstrahirani su metanolom uz primjenu mikrovalova te analizirani HPLC-UV/DAD sustavom. Bez obzira na dozu, više od 80 % TBA rasipalo se iz prvih 50 centimetara tla dva mjeseca nakon primjene herbicida (nakon 120 mm oborina). Tri mjeseca poslije (nakon žetve kukuruza) u tlu je ostalo manje od 4 % primijenjenog TBA, uglavnom u površinskim humusnim slojevima gdje se može očekivati adsorpcija TBA na organski ugljik. Gubitak TBA iz tla praćen je porastom masenih udjela DET-a, osobito u razdoblju rijetkih oborina i najviših prosječnih temperatura tla. Najviše razine DET-a određene su u humusnim slojevima tla. Postojanost TBA u tlu značajno negativno korelira sa sadržajem humusa, što upućuje na biorazgradnju kao glavni put disipacije TBA u humusnom tlu. Doza herbicida ne utječe značajnije na brzinu disipacije u humusnom sloju tla, ali u tlu s manje od 1 % organskog ugljika može se očekivati brža disipacija TBA pri dvostrukoj nego pri propisanoj dozi

Dinamika disipacije terbutilazina u tlu tijekom vegetacije kukuruza

Ever since terbuthylazine (TBA) replaced atrazine in herbicide crop treatment, its much greater persistence has raised considerable environmental concern. The aim of our field experiment was to establish the dissipation dynamics of TBA and its degradation product desethylterbuthylazine (DET) in soil over five months of maize growth. We applied TBA as part of pre-emergent treatment in the regular and double-the-regular amounts. Soil samples were collected periodically at the following depths: 0-10 cm, 10-20 cm, 20-30 cm, and 30-50 cm. For TBA and DET soil residue analysis we used microwave-assisted extraction with methanol, followed by HPLC-UV/DAD. Regardless of the application rate, more than 80 % of the applied TBA dissipated from the first 50 cm of soil in the two months after herbicide application and 120 mm of rainfall. Three months later (at maize harvest), less than 4 % of total TBA remained in the soil, mostly in the top 20 cm rich with organic carbon on which TBA is likelier to adsorb. The loss of TBA from soil coincided with the rise in DET, especially the top soil layers, during the periods of low rainfall and highest soil temperatures. This points to biodegradation as the main route of TBA dissipation in humic soils. The applied amount had no significant effect on TBA dissipation in the top (humic) layers, but in the layers with less than 1 % of organic carbon, it was higher when the double-the-regular dose was applied.Terensko istraživanje dinamike disipacije herbicida terbutilazina (TBA) i njegova razgradnog produkta deetilterbutilazina (DET) u tlu provodilo se tijekom pet mjeseci proizvodnje kukuruza. Terbutilazin je primijenjen kao zemljišni herbicid u propisanoj dozi i u dvostruko višoj dozi od propisane. Uzorci tla periodično su skupljani pri dubinama 0-10 cm, 10-20 cm, 20-30 cm i 30-50 cm. Ostaci herbicida u tlu ekstrahirani su metanolom uz primjenu mikrovalova te analizirani HPLC-UV/DAD sustavom. Bez obzira na dozu, više od 80 % TBA rasipalo se iz prvih 50 centimetara tla dva mjeseca nakon primjene herbicida (nakon 120 mm oborina). Tri mjeseca poslije (nakon žetve kukuruza) u tlu je ostalo manje od 4 % primijenjenog TBA, uglavnom u površinskim humusnim slojevima gdje se može očekivati adsorpcija TBA na organski ugljik. Gubitak TBA iz tla praćen je porastom masenih udjela DET-a, osobito u razdoblju rijetkih oborina i najviših prosječnih temperatura tla. Najviše razine DET-a određene su u humusnim slojevima tla. Postojanost TBA u tlu značajno negativno korelira sa sadržajem humusa, što upućuje na biorazgradnju kao glavni put disipacije TBA u humusnom tlu. Doza herbicida ne utječe značajnije na brzinu disipacije u humusnom sloju tla, ali u tlu s manje od 1 % organskog ugljika može se očekivati brža disipacija TBA pri dvostrukoj nego pri propisanoj dozi

Chemical Composition and Physical Properties of “Pale Yellow” Naphtalan

The Pale Yellow (PY) Naphthalan is potentially a new treatment modality for some oral mucosal and dermatological diseases. Its chemical composition and physical properties were studied by standard and sophisticated methods. Special attention was paid to steranes and hopanes as favorable components and to aromatics as unfavorable compounds. PY Naphthalan is predominantly composed of saturated aliphatic hydrocarbons of different structures, and of hydrocarbons comprising aromatic ring(s) (< 15%). Among aromatics, 98% were monoaromatics and 2% diaromatics, while 16 polycyclic aromatic hydrocarbons designated by US Environmental Protection Agency as priority pollutants were found at minimum detectability levels. Steranes and hopanes appeared in native geogenic clusters of homologs and each of identified compounds was in native geogenic configuration. Steranes were in the range from norcholestanes up to propyl cholestanes and hopanes up to pentakishomohopanes. The content of steranes and hopanes was relatively high. Compared to the other naphthalan products, the composition of PY Naphthalan is remarkably improved. Physical properties make PY Naphthalan convenient for application. (doi: 10.5562/cca1886

Organochlorine Pesticides and Polychlorinated Biphenyls in Atmospheric Particles Collected in Zagreb, Croatia

We studied the occurrence and levels of hexachlorobenzene, &alpha;-, &beta;-, and &gamma;-hexachlorocyclo-hexane, 4,4\u27-DDT, 4,4\u27-DDE, 4,4\u27-DDD, and 17 PCBs (six indicator and eleven other toxicologically significant congeners) in PM10 and/or PM2.5 particle fractions collected between 2000 and 2003 and in 2010 at a site in the northern residential part of Zagreb, Croatia. Twenty-four-hour particle samples were collected on glass or quartz microfibre filters from approximately 100 m3 of ambient air per filter. Filters with particles collected over seven consecutive days were combined for ultrasonic extraction with 1:1 acetone:n-hexane mixture followed by capillary gas chromatography with electron capture detection. In the monitored periods, the mass concentrations of organochlorine compounds in atmospheric particles were characteristic of global environmental pollution and showed a decreasing trend. Local input was observed only for &gamma;-hexachlorocyclohexane. There were no pronounced seasonal variations in the mass fraction levels of any pesticide or PCB in airborne particles. A decreasing trend in the mass concentrations of some compounds with higher air temperatures was mostly related to the lower particle concentrations in warmer seasons and, consequently, to less particle-bound organochlorine compounds in the atmosphere

Obogaćivanje i karakterizacija bakterija aktivnih u razgradnji polikloriranih bifenila kao potencijalnih starter kultura za biološki oporavak onečišćenih tala

The main objective of our study was to obtain seed cultures for enhancing the transformation of polychlorinated biphenyls (PCBs) in contaminated soil of the transformer station in Zadar, Croatia, damaged during warfare activities in 1991. For enrichment, six soil samples were collected from different polluted areas and microcosm approach, stimulating the growth of biphenyl-degrading bacteria, was employed. Enrichment experiments resulted in the selection of two fast growing mixed cultures TSZ7 and AIR1, originating from the soil of the transformer station and the airport area, respectively. Both cultures showed significant PCB-degrading activity (56 to 60 % of PCB50 mixture was reduced after a two-week cultivation). Furthermore, the cultures displayed similar PCB-degrading competence and reduced di-to tetrachlorobiphenyls more effectively than penta- to hepta-chlorobiphenyls. Strain Z6, identified as Rhodococcus erythropolis, was found to be the only culture member showing PCB-transformation potential similar to that of the mixed culture TSZ7, from which it was isolated. Based on the metabolites identified in the assay with the single congener 2,4,4’-chlorobiphenyl, we proposed that the strain Z6 was able to use both the 2,3-and 3,4-dioxygenase pathways. Furthermore, the identified metabolites suggested that beside these pathways another unidentified pathway might also be active in strain Z6. Based on the obtained results, the culture TSZ7 and the strain Z6 were designated as potential seed cultures for bioremediation of the contaminated soil.Osnovni je cilj istraživanja bio dobivanje katabolički aktivnih kultura za ubrzanje razgradnje polikloriranih bifenila (polychlorinated biphenyls – PCBs) u onečišćenom tlu u blizini zadarske trafostanice (Hrvatska) koja je oštećena tijekom domovinskoga rata godine 1991. Obogaćivanje aktivnih bakterija provedeno je iz 6 uzoraka tala sakupljenih s različitih područja onečišćenih polikloriranim bifenilima te je primijenjena metoda submerznog uzgoja uz poticanje rasta bakterija koje mogu razgrađivati bifenil. Tim su postupkom izdvojene dvije mješovite kulture (TSZ7 i AIR1, potječu iz tla u blizini trafostanice i zračne luke), koje su najbolje rasle na bifenilu. Obje su kulture pokazale podjednaku sposobnost razgradnje bifenila (nakon dva tjedna uzgoja razgrađeno je 56-60 % smjese PCB50) te su brže razgrađivale di-, tri- i tetraklorbifenile nego penta-, heksa- i heptaklorbifenile. Soj Z6, Rhodococus erythropolis, bio je jedini član mješovite kulture TSZ7 koji je pokazao sposobnost razgradnje polikloriranih bifenila. Na osnovi metabolita identificiranih u pokusu s pojedinačnim kongenerom (2,4,4\u27-klorbifenilom) i sojem Z6 pretpostavlja se da su u razgradnji tog spoja uključena oba enzima, 2,3- i 3,4-dioksigenaza. Također se pretpostavlja da soj Z6 može aktivirati i neki drugi, neidentificirani metabolički put u razgradnji polikloriranih bifenila. Temeljem postignutih rezultata mješovita kultura TSZ7 i soj Z6 odabrani su kao starter kulture za biološki oporavak onečišćenih tala

Effect of Organic and Mineral Soil Fractions on Sorption Behaviour of Chlorophenol and Triazine Micropollutants

This article compares the sorption behaviour of 2,4,6-trichlorophenol, 2,3,4,6-tetrachlorophenol, pentachlorophenol, chlorotriazine atrazine, methylthiotriazine ametryn, methoxytriazine atratone, hydroxyatrazine, and didelakylated atrazine in a topsoil and an aquifer sediment before and after removal of sorbent organic matter and in humic acid. Freundlich isotherm coeffi cients Kf and 1/n and free energy change (∆G°) were calculated for all compounds in all sorbents. According to sorbent pH values, chlorophenolate anions and uncharged triazine species dominated in all sorption experiments with topsoil and aquifer sediment. In experiments with humic acid, chlorophenols, atrazine, and didealkylated atrazine existed almost completely as neutral species, whereas protonated species dominated for hydroxyatrazine, atratone, and ametryn. In addition to a hydrophobic partition, sorption of all compounds in native soil and sediment sorbents includes specifi c, more polar interactions, which greatly depend on sorbate acidity/ basicity, specifi c properties of the sorbent organic matter and of mineral surface, as well as on the system pH. A signifi cantly greater sorption intensity of all compounds in “organic-free” than in the native aquifer sediment confi rmed the importance and possible dominance of mineral surface in the sorption process. Sorption intensity of chlorophenol and triazine compounds in humic acid was closely related to compound hydrophobicity. Greater sorption of almost completely protonated hydroxyatrazine than of the more hydropohobic but uncharged atrazine indicated different humic acid reaction sites for two compounds and consequently different sorption mechanisms.Uspoređena je sorpcija 2,4,6-triklorfenola, 2,3,4,6-tetraklorfenola i pentaklorfenola te različito supstituiranih triazinskih spojeva - klortriazina atrazina, metiltiotriazina ametrina, metoksitriazina atratona i razgradnih produkata atrazina hidroksiatrazina i didealkiliranog atrazina – u površinskom tlu i sedimentu vodonosnika prije i nakon uklanjanja organske tvari te u huminskoj kiselini. Izračunani su koefi cijenti Freundlichove izoterme Kf i 1/n te izmjena slobodne energije (∆G°) za sve spojeve i sorbense. U skladu s pH-vrijednostima sorbensa u svim su sorpcijskim pokusima s nativnim tlom i sedimentom prevladavali klorfenolatni anioni i neutralni triazinski spojevi. U pokusima s huminskom kiselinom klorfenoli, atrazin i didealkilirani atrazin postojali su kao neutralne vrste, dok su hidroksiatrazin, atraton i ametrin bili većim dijelom protonirani. Sorpcija svih spojeva u prirodnom tlu i sedimentu uključuje uz hidrofobnu particiju i specifi čne polarnije interakcije ovisne o kiselosti/bazičnosti sorbata, specifi čnim svojstvima organske tvari i mineralne površine sorbensa te o pH-vrijednosti sustava. Intenzitet sorpcije svih spojeva u sedimentu iz kojeg je uklonjena organska tvar bio je značajno veći od sorpcije u prirodnom sedimentu, što potvrđuje važnost i moguću dominantnu ulogu mineralne površine u sorpcijskom procesu. Intenzitet sorpcije klorfenola te klortriazina, metiltiotriazina i metoksitriazina u huminskoj kiselini korelirao je s hidrofobnosti spojeva. Veća sorpcija gotovo potpuno protoniranog hidroksiatrazina od hidrofobnijeg, ali neutralnog atrazina upućuje na različita reakcijska mjesta za ova dva spoja, a time i na različite mehanizme sorpcije u huminskoj kiselini

Pesticides and other Persistent Organochlorine Compounds in the Environment in Croatia

Istraživanja podrijetla i raspodjele postojanih organoklorovih (OC) spojeva u okolišu u nas uključuju organoklorove (OC) pesticide, poliklorirane bifenile (PCB), poliklorirane dibenzop- dioksine (PCDD) i poliklorirane dibenzofurane (PCDF). Njihove razine ispituju se u površinskim, podzemnim i pitkim vodama, moru, riječnim i morskim sedimentima, tlu, zraku, oborinama te iglicama crnogoričnog drveća. U vodama su u proteklih dvadesetak godina najčešće detektirani pesticidi bili p,p’-DDT i njegovi metaboliti, gama-heksaklorcikloheksan (gama-HCH) i heksaklorbenzen. Najviše razine PCB-a izmjerene su u vodama krškog područja. Malobrojni podaci o OC spojevima u tlu/sedimentima upućuju na povišene razine PCB-a u tlu uz oštećene trafostanice i unutar zračnih luka. Razine PCDD-a i PCDF-a oko 50 puta više od onih tipičnih za seoska i urbana područja izmjerene su u tlu neposredno uz postrojenje kloralkalne elektrolize. OC pesticidi i PCB-i detektirani su u oborinama i zraku na području Zagreba te u iglicama crnogoričnog drveća na različitim lokacijama. Uočen je skorašnji unos gama-HCH i p,p’-DDT-ja u atmosferu. Najviše razine PCDD/PCDF-a u zraku na području Zagreba izmjerene su u industrijskom dijelu grada.Studies of origin and distribution of persistent environmental organochlorine (OC) pollutants in Croatia have comprised three groups of compounds: OC pesticides, polychlorinated biphenyls (PCB), and more recently polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF). The use of OC pesticides in Croatia is restricted, and hexachlorobenzene is even forbidden. PCBs may be used in closed systems only. The main source of PCDD/PCDF in the environment is combustion, but these also occur as byproducts in certain pesticide and other chemical formulations. Common to all those compounds are high hydrophobicity, poor solubility in water, and low volatility. They are rapidly and strongly sorbed by most soils and are often associated with bottom sediments in aquatic systems. Circulation of air masses, precipitation of particles onto which pollutants are sorbed, and wet depositions washing them out from the atmosphere may transport OC pollutants over long distances. The levels of persistent OC micropollutants in Croatia were investigated in surface, ground, and drinking water, sea water, river and marine sediments, soil, air, wet depositions, and coniferous tree needles. Most data collected for the last 20 years concern regular or periodical determination of OC pesticides in water. The most often detected compounds were p,p’-DDT and its metabolites, -hexachlorocyclohexane ( -HCH), and hexachlorobenzene. Recent measurements show that the concentrations of OC pesticides in different waters keep within the range of ecotoxicologically acceptable and legally prescribed values. The highest PCB levels (>100 ng/dm3) were measured in source and surface waters in karst areas where elimination of water pollutants by natural filtration through soil layers was almost negligible. The data on persistent OC compounds in soil and sediments are rare although, due to sorption and bioconcentration tendency, OC compounds are more likely to show higher levels in these media than in water. The most frequently detected OC pesticides in soils/sediments were the DDT-type compounds and -HCH. In most analysed soils and sediments PCB mass fractions were characteristic for global environmental pollution. Higher PCB levels were determined in soils collected in the close vicinity of transformer stations, in the airport areas, and close to some industrial plants. PCDD/PCDF levels in the airport soil kept within the range typical for urban and rural areas, whereas they rose by about 50 times in soils collected near a chloralkali electrolysis plant. Traces of OC pesticides and PCB were detected in wet depositions collected in urban and rural areas. The rain and snow samples collected in Zagreb contained traces of PCDD/PCDF and the highest concentrations at pg/dm3 level were measured for octa-CDD. The only data on OC pesticide, PCB and PCDD/PCDF levels in the ambient air were reported for air samples collected in 1997 and 1998 in the Zagreb city area. The highest pesticide concentrations were measured for -HCH. The highest PCDD/PCDF level was determined in the industrial zone of the city. The level of environmental pollution in a certain location can be evaluated through measurement of OC compounds in coniferous tree needles. All needle samples collected in the 1991–1998 period in different regions of Croatia contained OC pesticides and PCB. The mass fraction ratio _-HCH/_-HCH<1 found by the analysis of needle, air, and rain samples confirmed recent release of lindane in the environment as a consequence of its frequent local usage

Applicability of Liquid Chromatography with Time-of-Flight Mass Spectrometric Detection for Determination of Cyanuric Acid in Soil

Cyanuric acid (2,4,6-trihydroxy-1,3,5-triazine, CA) is a highly polar and hydrophilic degradation product of symmetric triazine herbicides, fairly stable under environmental conditions. We investigated the applicability of reversed-phase liquid chromatography coupled to time-of-flight mass spectrometry (LC-ToF-MS) for qualitative and quantitative determination of CA in soils of different origin and pedological characteristics. CA was ultrasonically extracted from soils either with a mixture of acetone and n-hexane (volume ratio = 2 : 1) or with methanol and analysed on a LiChrospher 100 CN column with ψ(acetonitrile,water) = 50 : 50 as the mobile phase for isocratic elution. The efficiency and selectivity of LC-ToF-MS determination, using the electrospray ionisation in negative mode and selective monitoring of deprotonated CA molecule (m/z 128), was evaluated with respect to injection volume, extracting solvent, and possible soil matrix interferences. The advantage of LC-ToF-MS over conventional HPLC with UVdiode array detection was the high ion detection selectivity minimising the interferences of coeluting species and the unambiguous identification of CA in soil extracts by accurate mass measurements of deprotonated molecule. (doi: 10.5562/cca2109