Florisil Column Chromatography Research Articles

Effect of gamma rays and accelerated electron beam on medullary lipids decomposition: influence of dose and irradiation temperature.

Ionizing radiation sterilization of non-defatted bone grafts has been found to deteriorate their quality and biocompatibility due to induction of lipid peroxidation products toxic for osteoblast-like cells. Therefore, the purpose of our study was to evaluate the effect of two types of ionizing radiation-gamma rays (G) or accelerated electron beam (EB) applied with two doses at different temperature conditions on hydrocarbons production, resulting from decomposition of palmitic and oleic acids-most abundant fatty acids in medullary lipids. Bone marrow samples isolated from femoral shafts of 6 male donors (aged 46-67 years) were irradiated with G or EB with doses of 25 or 35kGy at different temperature conditions (ambient or deep freezing temperature). Fresh-frozen, non-irradiated samples served as control. Marrow lipids were extracted with n-hexane (Soxhlet's method), hydrocarbons fraction isolated on Florisil column chromatography, separated by gas chromatography and detected by mass spectrometry. Irradiation of bone marrow with sterilization doses of ionizing radiation (G and EB) was found to induce lipid radiolysis as measured by resulting hydrocarbons production. The effect was dose-dependent, whereas no marked influence of radiation type was observed. In contrast, irradiation temperature had a profound effect on lipids decomposition which was partially prevented while irradiation was performed in deep frozen state. Defatting of bone grafts prior to ionizing radiation sterilization seems essential for their biocompatibility, whereas irradiation in a deep-frozen state might compromise the effectiveness of sterilization and needs further studies.

A new multistep purification method for simultaneously determining organic ultraviolet absorbents in fish tissue.

More information is required to improve our understanding of the presence of organic ultraviolet absorbents (UVAs) in organisms and the risks posed to biota. Effective removal of lipids in the determination of UVAs in biological samples is a sample-processing bottleneck. In this study, we optimized a multistep purification method for fish tissue samples extracted using an ultrasonic-assisted extraction method. The purification method involved performing Florisil column chromatography, redissolving the extract in ethanol, and then performing dispersive solid-phase extraction using primary and secondary amine, Florisil, and C18 silica sorbents. The purified samples were analyzed by gas chromatography-mass spectrometry. The method was effective and reliable, and was used to detect trace concentrations (ng/g) of 12 UVAs in fish tissue samples. The mean recovery range of the UVAs in fish tissue extracts was 65.4-118%, and the method detection limit range was 0.20-2.50ng/g dw. The validated method was used to analyze 12 UVAs in fish samples from a local supermarket.

Effect of water treatment process on organochlorine pesticide residue levels in Ahvaz water treatment plant 2

One of the main hazards of human life and health is the presence of pesticides in the aquatic system is. The Karun River is the surface water source in the preparation of drinking water for the city of Ahvaz city at the Ahvaz Water Treatment Plant (AWTP) #2. This study was done in order to investigate the statue of qualification and the quantification of the contamination of water entering into (AWTP #2) by selected organochlorine pesticides [(α, β, γ, δ )HCH, heptachlor, alderin, dielderin, (op’ , pp’ ) DDT, (α, β) endosulfan and metoxychlor], plus the water treatment effects on these pesticide residues removal. For this purpose, one composite sample from each of the water treatment process steps was taken monthly which was comprised of 20 grab samples in 2008. Water samples were acidified to pH < 2, extracted three times with n-hexane, and concentrated using a rotary vacuum evaporator for Florisil column chromatography cleanup and fractioned by elution with three different solvent mixtures of petroleum and diethyl ether. Finally, the elutes were concentrated to dryness using rotary vacuum evaporator and then the residues were dissolved in hexane and analyzed by GC- μECD. All 12 investigated organochlorine pesticides were detected. Results of this study indicated that concentration of investigated pesticides decreased (according to the kind of pesticide) by 20% to 80% and the mean of total concentration was reduced by 49% during water treatment process steps. There was a significant positive correlation (r=97.75%) between variation in the concentration of poisons and the total organic matter (KMnO4 value).

The Duquenois reaction revisited: mass spectrometric estimation of chromophore structures derived from major phytocannabinoids

Four major phytocannabinoids (∆8-tetrahydrocannabinol, ∆9-tetrahydrocannabinol, cannabidiol, and cannabinol, 100 mg each) were dissolved in Duquenois reagent containing vanillin and acetaldehyde in ethanol, and concentrated hydrochloric acid was added. The chromophores derived from the four cannabinoids were characterized by mass spectrometry after dichloromethane extraction and partial purification by Florisil column chromatography with dichloromethane-ethanol solutions, using a unique replacement technique, which caused various modes of peak shifts in mass spectra giving information for structural elucidation. It was disclosed that there were three types of condensates, among which the structures of two condensates could be delineated, but one condensate remains to be clarified. To our knowledge, this is the first report to simultaneously propose the structures of the Duquenois reaction chromophores for the four major phytocannabinoids.

Development of an Official Method for Measurement of Fluazinam Residues for Quarantine of Imported and Exported Horticultural Products

본 연구는 국내 및 수출입 원예작물의 일상적 잔류농약 검사에 활용 가능한 dinitroaniline계 광범위 살균제 fluazinam의 GC-ECD/MS 잔류 분석법을 확립하고자 하였다. 원예작물 중 채소류에서는 청양고추와 결구배추를, 과일류에서는 감귤과 사 과를 대표 시료로 선정하였고, 아세톤으로 추출된 fluazinam은 식염수로 희석하고, 수용액층을 n-hexane 액-액 분배법으로 회수하였으며, 회수된 추출액으로부터 fluazinam의 최종적 정제를 위하여 florisil 칼럼 크로마토그래피법으로 추가 정제하여 GC-ECD/MS 분석용 시료로 사용하였다. Fluazinam의 정량적 분석을 위하여 DB-17 capillary column을 적용한 GC-ECD 분석 조건을 확립하였으며, 각 작물별 4수준의 농도로 fluazinam을 인위 첨가하여 회수율을 분석하였다. 각 대표 원예작물에 대해 정량한계, 정량한계의 10, 50, 및 100배 수준에서 회수율을 검토한 결과 모든 처리농도에서 82.5-99.9% 수준을 나타내었 으며, 정량한계(LOQ)는 0.004mgㆍkg-1이었다. 반복 간 변이계수(CV)는 최대 6.6%를 나타내어 국제적 잔류분석 기준인 회수 율 70-120% 및 분석오차 10% 이내를 충족시키는 만족한 결과를 도출하였다. 또한 GC/MS SIM을 이용하여 실제 각 작물 시 료에 적용하여 재확인 하였다. 이상의 결과로 신규 fluazinam의 GC-ECD/MS 분석법은 검출한계, 회수율 및 분석오차 면에서 국제적 분석기준을 만족하는 신뢰성이 확보된 정량 분석법으로서 국내 및 수출입 검역을 위한 원예작물의 공정 잔류분석법으 로 사용 가능할 것이다.

GC-ECD/MS를 이용한 농산물 중 Quintozene의 잔류분석

Abstract Quintozene, pentachloronitrobenzene (PCNB) is a contact fungicide for control of soilbornephytopathogenic fungi during cultivation of diverse crops. It was introduced to agricultural use around 1930’sas a substitute for mercurial disinfectants. Although quintozene had been first registered in Korea on 1969.However, now it was banned to use due to its high residue levels in selected harvest products. Also, highpossibility is expected that the residue may be contained in imported agricultural commodities as it is stillused widely over the world. Therefore, this study was conducted to establish a determination method forquintozene residue in crops using GC/ECD/MS. Quintozene residue was extracted with acetonitrile fromrepresentative samples of five raw products which comprised hulled rice, soybean, Kimchi cabbage, greenpepper, and apple. The extract was diluted with saline water, and n-hexane partition was followed to recoverquintozene from the aqueous phase. Florisil column chromatography was additionally employed for finalclean up of the extract. The quintozene was quantitated by GLC with ECD, using a DB-1 capillary column.The crops were fortified with quintozene at 3 levels per crop. Mean recoveries ranged from 79.9% to 102.7%in five representative agricultural commodities. The coefficients of variation were less than 4.3%. Quantitativelimit of quintozene was 0.004 mg/kg in representative five crop samples. A GC/MS with selected-ionmonitoring was also provided to confirm the suspected residue. Therefore, this analytical method wasreproducible and sensitive enough to determine the residue of quintozene in agricultural commodities.Key words GC-ECD/MS, Quintozene, Residue

Distribution of polychlorinated biphenyl residues in several tissues of fish from the North End Lake, Port Elizabeth, South Africa

The concentrations and distribution of 6 PCB indicator congeners (IUPAC nos. 28, 52, 101, 138, 153, and 180) were measured in 236 organ samples of fish ( Cyprinus carpio and Oreochromis mossambicus ) from the North End Lake in Port Elizabeth, South Africa. Polychlorinated biphenyls (PCBs) were extracted from the fish muscles, gills, gonads and livers using USEPA method 8082, followed by a clean-up using concentrated sulphuric acid and florisil column chromatography. Analysis was achieved by gas chromatography–mass spectrometry (GC/MS) using the internal standard method. The concentrations of total PCBs in the liver, gonads, gills and muscle were 95.69, 57.49, 44.63, 34.14 ng∙g -1 lipid weight (lw) in C. carpio and 119.73, 59.21, 49.78, 34.63 ng∙g -1 (lw) in O. mossambicus , respectively. These values were relatively low compared to those reported in the literature. PCB levels were predictably highest in the lipid-rich livers. Individual congeners were not distributed homogeneously within the investigated organs. PCBs 153 and 138 were present at higher concentrations than other PCB congeners for both species. PCB contaminants in fish act as indicators of pollution in aquatic ecosystems and are a potential threat to human health when consumed. Keywords : PCBs, tissues, fish, GC/MS, biomagnification, North End Lake

Dissipation and Removal of the Etofenprox Residue during Processing in Spring Onion.

The dissipation and removal of the etofenprox residue was studied in spring onion grown under greenhouse conditions. Samples of spring onion were collected at 0, 1, 2, 4, 6, 8, 10, 12, and 14 days after last application, and removal rates of etofenprox by washing and drying processes were measured. Samples were extracted with acetone and partitioned with dichloromethane. The dichloromethane layer was then concentrated, cleaned up with florisil column chromatography, and analyzed with high-performance liquid chromatography-ultraviolet detector (HPLC-UVD). At the fortification levels of 0.5, 1.0, and 10 mg/kg, recoveries ranged from 92.0 to 107.7%, with a coefficient of variation of 4.3-7.9% (n = 3). The method limit of quantification (MLOQ) was found to be 0.05 mg/kg in spring onion. The half-lives of etofenprox in spring onion were found to be 9.5 and 7.9 days, at the single or double application rates. Removal rates of etofenprox were 21.6-43.9 and 66.6-88.5% by various washing or drying processes, respectively.

HPLC-UVD/MS를 이용한 농산물 중 Amisulbrom의 잔류분석

Abstract This experiment was conducted to establish an analytical method for residues of amisulbrom, asrecently developed an oomycete-specific fungicide showing inhibition of fungal respiration, in crops usingHPLC-UVD/MS. Amisulbrom residue was extracted with acetonitrile from representative samples of five rawproducts which comprised apple, green pepper, kimchi cabbage, potato and hulled rice. The extract was dilutedwith 50 mL of saline water and directly partitioned into dichloromethane to remove polar co-extractives in theaqueous phase. For the hulled rice sample, n-hexane/acetonitrile partition was additionally employed to removenon-polar lipids. The extract was finally purified by optimized Florisil column chromatography. On anoctadecylsilyl column in HPLC, amisulbrom was successfully separated from sample co-extractives andsensitively quantitated by ultraviolet absorption at 255 nm with no interference. Accuracy and precision of theproposed method was validated by the recovery test on every crop samples fortified with amisulbrom at 3concentration levels per crop in each triplication. Mean recoveries ranged from 85.3% to 105.6% in fiverepresentative agricultural commodities. The coefficients of variation were all less than 10%, irrespective ofsample types and fortification levels. Limit of quantitation (LOQ) of amisulbrom was 0.04 mg/kg as verifiedby the recovery experiment. A confirmatory method using LC/MS with selected-ion monitoring technique wasalso provided to clearly identify the suspected residue. The proposed method was sensitive, reproducible andeasy-to-operate enough to routinely determine the residue of amisulbrom in agricultural commodities.Key words Amisulbrom, HPLC-UVD/MS, Residue

Persistent organochlorine pesticide residue in tissues and blood of goat

The production commensurate with the demand for animal products including meat is increasing due to urbanization and increase in per capita income. However, meat and meat products meant for human consumption should also be safe and free from toxic contaminants. Presence of any xenobiotics in human food web is undesirable and unacceptable particularly in the wake of sanitary and phytosanitary (SPS) measures and strict regulations imposed by many countries on the ground of safety of health of the consumers. In the present study, certain organochlorinated pesticide (OCP) residues in tissues and in blood samples of goat were determined. All samples were analysed for residues of hexachlorocyclohexane (HCH) isomers, dichlorodiphenyltrichloroethane (DDT) isomers and metabolites, endosulfan isomers and metabolite, aldrin, heptachlor and dicofol. The tissue samples were extracted in soxhlet with hexane-acetone (1:1) and cleaned up by florisil column chromatography. The analysis was performed in capillary gas chromatograph equipped with electron capture detector (GC-ECD). The result indicated that 40% tissue samples were contaminated with HCH residues, while DDT and endosulfan were present in 32% samples. In blood samples, no HCH residue could be detected, but DDT and endosulfan were present in 10% and 30% samples, respectively.

생약 중 Fenpyroximate의 분석법 연구

Abstract Fenpyroximate is acaricide of pyrazole group. This acaricide have already been permitted for herbcultivation. This experiment was conducted to establish a determination method for fenpyroximate residue inherbal medicines using HPLC-PDA and HPLC-MS/MS. Fenpyroximate residue was extracted with acetonefrom samples of herbal which Liquorice Root (Glycyrrhiza uralensis) and Safflower Seed (Carthamustinctorius Linne). The extract was diluted with saturated saline water and dichloromethane liquid-liquidpartition (extraction) was followed to recover fenpyroximate from the aqueous phase. Amino propyl (NH 2 )and florisil column chromatography was additionally employed for final clean up of the extract. The fenpyro-ximate was quantitated by HPLC-PDA and HPLC-MS/MS. The herbals were fortified with fenpyroximate at2 or 3 levels per crop. Mean recovery ratio were ranged from 72.0 to 106.4%. The coefficients of variationwere ranged from 0.2 to 4.4. Therefore, this analytical method was reproducible and sensitive enough todetermine the residue of fenpyroximate in herbal medicines.Key words Fenpyroximate, Herbal medicine, HPLC-MS/MS, HPLC-PDA, LOQ

Ultra high performance liquid chromatography–time-of-flight high resolution mass spectrometry in the analysis of hexabromocyclododecane diastereomers: Method development and comparative evaluation versus ultra high performance liquid chromatography coupled to Orbitrap high resolution mass spectrometry and triple quadrupole tandem mass spectrometry

An efficient ultra high performance liquid chromatography (UHPLC)–time-of-flight high resolution mass spectrometry (TOF-HRMS) method was elaborated for the determination of hexabromocyclododecane (HBCD) diastereomers in fish samples and compared against UHPLC–Orbitrap-HRMS and UHPLC–triple quadrupole (QqQ) tandem MS (MS/MS) techniques. The TOF-HRMS analyzer was operated at high resolution (>10000 full width at half maximum (FWHM)) with scanning the m/z range from 600 to 700, to achieve picogram quantitation limits. The effects of various operational parameters on the instrumental response were systematically investigated. Evaluation of the influence of sample clean-up procedure steps on signal suppression effect including removal of the matrix components by means of destructive acidic treatment or non-destructive gel permeation chromatography (GPC), and additional Florisil column chromatography step showed that the analytical response of UHPLC–TOF-HRMS system is much more affected by the presence of matrix components in the final extracts in comparison with UHPLC–Orbitrap-HRMS and UHPLC–QqQ-MS/MS systems. The method was robustly validated and used for the analysis of eel (Anquilla anquilla) samples originating from a Latvian lake. UHPLC–TOF-HRMS showed a suitable performance under the optimized conditions: recoveries for three selected diastereomers in the range of 99–116%; repeatability and intermediate precision expressed as relative standard deviation (RSD) in the ranges of 2.3–7.1% and 2.9–8.1%, respectively. The elaborated method achieved instrumental limits of quantification (i-LOQ) of 0.9–4.5pg on column that were suitable for the trace analysis of three HBCD diastereomers, corresponding to the method limits of quantification (m-LOQ) of 7.0–29pgg−1 wet weight (w.w.). The efficiency of UHPLC–TOF-HRMS method was evaluated by comparing the performance characteristics and analytical data from real samples with the validation data and real sample results obtained by applying UHPLC–Orbitrap-HRMS and UHPLC–QqQ-MS/MS techniques for the analysis of HBCD in the same fish samples. Statistical assessment of the experimental data by means of the Fiedman's test revealed that UHPLC–TOF-HRMS, UHPLC–QqQ-MS/MS and UHPLC–Orbitrap-HRMS techniques produced adequate and similar results regarding the HBCD content in fish samples. The presence of HBCD diastereomers was confirmed in all the analyzed eels at concentrations up to 554pgg−1 w.w. for total HBCD and a diastereomer pattern typical for aquatic biota was observed with strong predominance of α-HBCD. The UHPLC–TOF-HRMS is an appropriate technique for diastereomer-specific quantification of HBCD content in fish samples.

전자선 조사한 아몬드(Prunus amygosalus L.)와 땅콩(Arachis hypogaea)에서 유래한 지방분해산물 분석

아몬드와 땅콩의 비조사 시료와 1, 3, 5, 10 kGy로 전자선을 조사한 시료에서 유도된 hydrocarbon류의 생성량을 분석하기 위하여 지방을 n-hexane으로 추출하여 florisil column으로 분리 및 GC/MS로 분석하였다. 전자선 조사된 아몬드와 땅콩에서 유래한 hydrocarbon류는 oleic acid에서 1,7-hexadecadiene(<TEX>$C_{16:2}$</TEX>)과 8-heptadecene(<TEX>$C_{17:1}$</TEX>), linoleic acid에서 1,7,10-hexadecatriene(<TEX>$C_{16:3}$</TEX>)과 6,9-heptadecadiene(<TEX>$C_{17:2}$</TEX>), 그리고 palmitic acid에서 1-tetradecene(<TEX>$C_{14:1}$</TEX>) 및 pentadecane(<TEX>$C_{15:0}$</TEX>) 생성되었고, oleic acid와 palmitic acid에서는 <TEX>$C_{n-2}$</TEX>, linoleic acid에서는 <TEX>$C_{n-1}$</TEX> 화합물이 보다 더 높게 생성되었다. 전자선을 1, 3, 5, 10 kGy의 선량별로 조사한 시료에서 생성된 hydrocarbon류의 함량은 조사선량에 따라 증가하였고 비조사 시료에서는 확인되지 않았다. 특히, oleic acid와 linoleic acid에서 유래한 1,7-hexadecadiene(<TEX>$C_{16:2}$</TEX>), 8-heptadecene(<TEX>$C_{17:1}$</TEX>)과 1,7,10-hexadecatriene(<TEX>$C_{16:3}$</TEX>) 및 6,9-heptadecadiene(<TEX>$C_{17:2}$</TEX>)의 경우 아몬드와 땅콩 모두에서 다른 hydrocarbon류에 비해 전자선 조사에 의한 생성량이 높게 나타난바 전자선 조사유무 판별 marker로 사용 가능함을 확인하였다. Food irradiation has recently become one of the most successful techniques to preserve food with increased shelf life. This study aims to analyze hydrocarbons in almonds (Prunus amygosalus L.) and peanuts (Arachis hypogaea) induced by electron beam irradiation. The samples were irradiated at 0, 1, 3, 5 and 10 kGy by e-beam and using florisil column chromatography fat, and content was extracted. The induced hydrocarbons were identified using gas chromatography-mass spectrometry (GC/MS). The major hydrocarbons in both irradiated samples were 1,7-hexadecadiene (<TEX>$C_{16:2}$</TEX>) and 8-heptadecene (<TEX>$C_{17:1}$</TEX>) from oleic acid, 1,7,10-hexadecatriene (<TEX>$C_{16:3}$</TEX>) and 6,9-heptadecadiene (<TEX>$C_{17:2}$</TEX>) from linoleic acid and 1-tetradecene (<TEX>$C_{14:1}$</TEX>) and pentadecane (<TEX>$C_{15:0}$</TEX>) from palmitic acid. Concentrations of the hydrocarbons produced by e-beam were found to be depended upon the composition of fatty acid in both almonds and peanuts. The <TEX>$C_{n-2}$</TEX> compound was found to be higher than <TEX>$C_{n-1}$</TEX> compound in oleic acid and palmitic acid, while in case of linoleic acid, <TEX>$C_{n-1}$</TEX>compound was higher than <TEX>$C_{n-2}$</TEX> compound. The radiation induced hydrocarbons were detected only in irradiated samples, with 1 kGy or above, and not in the non-irradiated ones. The production of 1,7-hexadecadiene (<TEX>$C_{16:2}$</TEX>), 8-heptadecene (<TEX>$C_{17:1}$</TEX>), 1,7,10-hexadecatriene (<TEX>$C_{16:3}$</TEX>) and 6,9-heptadecadiene (<TEX>$C_{17:2}$</TEX>), in high concentration gave enough information to suggest that these may be the possible marker compounds of electron beam irradiation in almonds and peanuts.

Content of polychlorinated dibenzo-p-dioxins, dibenzofurans and dioxin-like polychlorinated biphenyls in fish from Latvian lakes

Seventeen polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/PCDFs) of the highest priority as well as twelve dioxin-like polychlorinated biphenyls (dl-PCBs) were analyzed in the muscle tissues of the following freshwater fish species sampled from eleven Latvian freshwater lakes: perch (Perca flavescens), carp (Cyprinus carpio), eel (Anguilla rostrata), bream (Abramis brama), chub (Leuciscus cephalus), pike (Esox lucius), sheatfish (Silurus glanis) and roach (Rutilus). To analyze the selected persistent organic pollutants in fish matrices, an optimization of EPA-1613 and EPA-1668A clean-up procedures was carried out, followed by validation of the analytical procedure according to Commission Regulation (EC) No 1883/2006. The adopted analytical procedure was in compliance with requirements of the more recent Commission Regulation (EU) No 252/2012. Modifications of carbon column chromatography clean-up and separation steps were used for treatment of the fish samples. Other clean-up procedure stages were performed according to the methods EPA-1613 and EPA-1668A and involved gel permeation chromatography (GPC), as well as manual acidic silica and Florisil column chromatography for purification and fractionation of the samples. An isotope dilution method was used for the qualitative and quantitative determination of individual congeners. Analytes of interest were separated and detected using gas chromatography – high resolution mass spectrometry. The concentration of PCDD/PCDFs and dl-PCBs in freshwater fish and eel samples ranged from 0.05 to 8.0pg WHO(1998)-PCDD/PCDF-PCB-TEQ g−1 fresh weight. These levels are below the EU maximum permissible limits although calculation of the content of these compounds relative to the weight of fat shows contamination levels similar to those found in Baltic herring and sprats, that are known to be highly contaminated. A difference in congener pattern between the Baltic Sea fish and freshwater fish was detected with lower contribution of 2,3,4,7,8-PeCDF to the contamination of inland water fish.

GC/ECD와 GC/MS를 이용한 농산물 중 Picoxystrobin의 분석법 개발

BACKGROUND: This study was conducted to develop analytical method for picoxystrobin in agricultural commodities using GC/ECD and GC/MS. METHODS AND RESULTS: Each steps of analytical method were optimized for determining picoxystrobin residues in various agricultural commodities. The developed methods include acetone extraction, n-hexane/saline water partition and florisil column chromatography for analysis of all samples (apple, potato, green pepper, hulled rice and soybean), and in addition to these steps, solid phase extraction (SPE) was used for analysis of green pepper and n-hexane/acetonitrile partition was used for analysis of hulled rice and soybean. The instrumental conditions were tested for quantitation in GC/ECD and for confirmation in GC/MS. Recovery was in the range of 86~109% with RSD <TEX>${\leq}$</TEX>10.2% and the quantitation limits (LOQ) of method were 0.025 mg/kg in all agricultural commodities. CONCLUSION: The result showed that the developed method can be used to determine picoxystrobin residue in agricultural commodities.

Liquid Chromatographic Determination of Etofenprox Residues in Foods with Mass-Spectrometric Confirmation

BACKGROUND: An official analytical method was developed to determine etofenprox residues in agricultural commodities using high-performance liquid chromatography (HPLC). METHODS AND RESULTS: The etofenprox residue was extracted with acetone from representative samples of five raw products which comprised rice grain, apple, mandarin, cabbage, and soybean. The extract was then serially purified by liquid-liquid partition and Florisil column chromatography. For rice and soybean samples, acetonitrile/n-hexane partition was additionally coupled to remove nonpolar lipids. Reversed phase HPLC using an octadecylsilyl column was successfully applied to separate etofenprox from co-extractives. Intact etofenprox was sensitively detected by ultraviolet absorption at 225 nm. Recovery experiment at the quantitation limit validated that the proposed method could apparently determine the etofenprox residue at 0.02 mg/kg. Mean recoveries from five crop samples fortified at three levels in triplicate were in the range of 93.6∼106.4%. Relative standard deviations of the analytical method were all less than 10%, irrespective of crop types. A selected-ion monitoring LC/mass spectrometry with positive atmospheric-pressure chemical ionization was also provided to confirm the suspected residue.

Simultaneous Determination of Orysastrobin and Its Isomers in Rice Using HPLC-UV and LC-MS/MS

Orysastrobin is a new strobilurin-type fungicide to control leaf and panicle blast and sheath blight in rice. An analytical method was developed to determine the residues of orysastrobin and its two isomers, the main metabolite F001 and the major impurity F033, in hulled rice by the use of high-performance liquid chromatography with ultraviolet photometry (HPLC-UV) and liquid chromatography with tandem mass spectrometry (LC-MS/MS). All compounds were extracted with acetone from hulled rice samples. The extract was diluted with saline water, and an extraction step using dichloromethane/n-hexane partition was used to recover analytes from the aqueous phase. An n-hexane/acetonitrile partition and Florisil column chromatography were employed to further remove interfering coextractives prior to instrumental analysis. An octadecylsilyl column was successfully applied to identify orysastrobin and its isomers in sample extracts. Net recovery rates of orysastrobin, F001, and F033 from fortified samples ranged from 80.6 to 114.8% using HPLC-UV and LC-MS/MS. Relative standard deviations for the analytical methods were all <20%, and the quantification limits of the method were in the 0.002-0.02 mg/kg range. The proposed methods were reproducible and sufficiently accurate to evaluate the terminal residue of orysastrobin and its isomers in rice.

Determination of Buprofezin Residues in Rice and Fruits Using HPLC with LC/MS Confirmation

A high-performance liquid chromatographic (HPLC) method was developed to determine buprofezin residues in hulled rice and fruits. The buprofezin residue was extracted with acetone and the extract was stepwise purified by liquid-liquid partition and Florisil column chromatography. For rice samples, acetonitrile/n-hexane partition was additionally employed to remove nonpolar lipids. Reversed phase HPLC using an octadecylsilyl column was successfully applied to separate buprofezin from sample co-extractives, as detected by ultraviolet absorption at 250 nm. Recovery experiment at the limit of quantitation validated that the proposed method could evidently determine the buprofezin residue at the level of 0.02 mg/kg. Mean recoveries from hulled rice, apple, pear, and persimmon samples fortified at three tenfold levels were in the range of 80.8~85.2%, 89.1~98.4%, 88.8~95.7% and 90.8~96.2%, respectively. Relative standard deviations of the analytical method were all less than 5%, irrespective of sample types. A selected-ion monitoring LC/mass spectrometry with positive electrospray ionization was also provided to sensitively confirm the suspected residue.

GC-ECD/MS를 이용한 농산물 중 Captan, Folpet, Captafol 및 Chlorothalonil의 잔류분석법

A gas chromatographic (GC) method was developed to determine residues of captan, folpet, captafol, and chlorothalonil, known as broad-spectrum protective fungicides for the official purpose. All the fungicide residues were extracted with acetone containing 3% phosphoric acid from representative samples of five agricultural products which comprised rice, soybean, apple, pepper, and cabbage. The extract was diluted with saline, and dichloromethane partition was followed to recover the fungicides from the aqueous phase. Florisil column chromatography was additionally employed for final cleanup of the extracts. The analytes were then determined by gas chromatography using a DB-1 capillary column with electron capture detection. Reproducibility in quantitation was largely enhanced by minimization of adsorption or thermal degradation of analytes during GLC analysis. Mean recoveries generated from each crop sample fortified at two levels in triplicate ranged from 89.0~113.7%. Relative standard deviations (RSD) were all less than 10%, irrespective sample types and fortification levels. As no interference was found in any samples, limit of quantitation (LOQ) was estimated to be 0.008 mg/kg for the analytes except showing higher sensitivity of 0.002 mg/kg for chlorothalonil. GC/Mass spectrometric method using selected-ion monitoring technique was also provided to confirm the suspected residues. The proposed method was reproducible and sensitive enough to determine the residues of captan, folpet, captafol, and chlorothalonil in agricultural commodities for routine analysis.

Occurrence of organochlorine pesticide residues in eggs, chicken and meat in Jordan

Organochlorine pesticide (OCP) residues in 519 samples; comprising eggs, chicken and meat (lamb and beef), collected from Jordan were determined. All samples were analyzed for their residual contents of aldrin, dichlorodiphenyltrichloroethane and metabolites (DDTs), dieldrin, endosulfan isomers, endrin, hexachlorocyclohexane isomers (HCHs), heptachlor, heptachlor epoxide and hexachlorobenzene (HCB). The samples were Soxhlet extracted for 8 h in 250 mL petroleum ether. The cleanup of the samples was performed by Florisil column chromatography and analysis was done on a gas chromatography equipped with an electron capture detector (GC-ECD). The results indicated that 28% (38/134), 20% (23/115) and 49% (131/270) of the examined eggs, chicken and meat samples, respectively, were contaminated with OCP residues. HCHs and DDTs are the most prominently noticed compounds, as they were detected at a high incidence. On the other hand, heptachlor, heptachlor epoxide, HCB, aldrin and endrin compounds were only present in less than 7% of the analyzed samples. These residues are present despite complete ban on the use of OCPs for agricultural purposes in Jordan. No residues of op′-DDD, op′-DDT, dieldrin, α-endosulfan and β-endosulfan were detected.