Comparison of gas and high performance liquid chromatography with selective detection for determination of triazine herbicides and their degradation products extracted ultrasonically from soil

Abstract

Comparison of gas and high performance liquid chromatography with selective detection for determination of triazine herbicides and their degradation products extracted ultrasonically from soil GC and HPLC with selective detectors were compared for simultaneous determination of triazine herbicides simazine, atrazine, propazine, terbuthylazine, cyanazine, ametryn, prometryn, and atraton, and of their dealkylated degradation products in soil. The compounds were ultrasonically extracted from spiked agricultural soil samples (organic matter content a 5%) with a 2:1 acetone:n-hexane mixture. High efficiency of GC capillary column and high selectivity of the thermionic sensitive detector (TSD) and ion trap detector (ITD) made it possible to directly analyse uncleaned soil extracts and determine all 12 compounds in one run. In reversed-phase HPLC with diode-array detector (DAD), the co-elution of soil matrix components interfered with the determination of methylthiotriazines and terbuthylazine. The recovery of triazine compounds, determined by GC-TSD, from a silty sand soil (organic matter content 1.82%, pH 6.22) spiked at levels of 15 -600 ng g -1 , were 70 -90% (RSD 9 -19%), except for deisopropylatraton (38%). GC-TSD analysis with detection limits of 5 -15 ng g -1 for chloro-and methylthiotriazines and 30 ng g -1 for methoxytriazines was more sensitive than GC-MS(ITD). GC analysis with electron capture detection was sensitive for some chlorotriazines, but a reliable compound quantification in complex chromatograms of uncleaned soil of extracts was not possible. For all compounds save didealkylatrazine, HPLC-DAD was at least two times less sensitive than GC-TSD. Soil/sediment organic matter, clay and silt content, and pH were identified as matrix characteristics which might affect ultrasonic extraction recovery of a particular compound.

Multiresidue analysis of pesticides in soil by liquid-solid extraction procedure

“…The recovery values of most of the selected pesticides and experimental parameters are shown to be higher than 70%, and therefore they may be considered as acceptable in terms of method confidence (Taverniers, et al, 2004). As shown in figure 1, somewhat lower recoveries were obtained for: carbofuran and the combination of FL, 130 as sorbent and AC-HEX as elution solvent, and SILICA and AC-HEX; diazinon and the combination of Al 2 O 3 and EA-AC; and aldrine with combined FL, 130 and AC-HEX, and SILICA and Al 2 O 3 with both elution solvents.…”

“…Numerous methods of analysis were developed, mostly using the conventional liquid-liquid extraction (LLE) or Soxhlet extraction. Although these extraction procedures may be considered conventional, no small number of publications dealing with their applications in pesticide residues determination in samples of different origin can be found in recent years (Kreuzig et al, 2000;Doong and Liao, 2001;Bavcon et al, 2003;Caballo-Lopez and Luque de Castro, 2003;Kodaka et al, 2003;Monkiedje et al, 2003;Navarro et al, 2003;Nawab et al, 2003;Stipicevic et al, 2003;Sassman et al, 2004;Barra et al, 2005;Wanga et al, 2008). On the other side, as these methods are part of a standard procedure, many laboratories currently use them for routine analysis.…”

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

“…The samples were analysed on an Rtx-5MS column (Restek, Bellefonte, PA, USA) under the same conditions as described earlier. 36 …”

“…36 Briefly, a 5 g portion of wet industrial soil (Ind Soil 1-4) was sonicated with 20 mL of ψ(acetone, n-hexane) = 2 : 1 mixture for 5 min. After being centrifuged at 425 g, the supernatant was decanted and the extraction was repeated with a new 10 mL portion of the same solvent mixture.…”

“…To minimize the solventmatrix effect on the GC detector response to triazine herbicides, the matrix-matched standards were prepared by adding increasing volumes of a standard mixture of triazine compounds in acetone to 5 mL aliquots of blank extract of Forest Soil. 36 For the LC determination of cyanuric acid, industrial soil samples were extracted with ψ(acetone, n-hexane) = 2 : 1 mixture as described above. The extract was evaporated to dryness under a stream of nitrogen and the residue was redissolved in 1.0 mL of 0.01 mol L -1 phosphate buffer, pH = 7.2, for the HPLC-UV(DAD) determination or in 1.0 mL of LC-grade water for the LC-ToF-MS determination.…”