DB-5 Capillary Column Research Articles

Removal of N-nitrosopyrrolidine from GAC by a three-dimensional electrochemical reactor: degradation mechanism and degradation path.

Nitrogen-containing disinfection by-products (N-DBPs) produced in the process of drinking water disinfection are widely concerning due to the high cytotoxicity and genotoxicity. It is due to the difficulty of natural degradation of N-DBPs in water and the fact that conventional treatment systems do not effectively treat N-DBPs in drinking water. In this study, N-nitrosopyrrolidine (NPYR) in water was electrocatalytically degraded by a three-dimensional electrode reactor (3DER). This system applied graphite plates as anode and cathode. The granular activated carbon (GAC) was used as third electrode. The degradation of NPYR using a continuous flow three-dimensional electrode reactor was investigated by examining the effects of flow rate, current density, electrolyte concentration, and pollutant concentration on the degradation efficiency, energy consumption, and reaction kinetics of GAC particle electrodes. The results showed that the optimal operating conditions were flow rate = 0.45mL/min, current density = 6mA/cm2, Na2SO4 concentration = 0.28mol/L, and NPYR concentration = 20mg/L. Under optimal conditions, the degradation of NPYR exceeded 58.84%. The main contributor of indirect oxidation was deduced from free radical quenching experiments. NPYR concentration was measured by GC-MS with DB-5 capillary column, operating in full scan monitoring mode for appropriate quantification of NPYR and intermediates. Based on the identification of reaction intermediates, a possible pathway for the electrochemical oxidation of NPYR on GAC particle electrodes was proposed.

Trihalomethanes and physicochemical quality of drinking water in Addis Ababa, Ethiopia

BackgroundTrihalomethanes (THMs) are the most dominant fraction of all the byproducts formed during chlorination of water. Disinfection by product (DBP) formation in water is a function of numerous factors, including pH, temperature, residual chlorine, source water characteristics, and organic matter. No study has determined the THM level in the drinking water supply of Addis Ababa, Ethiopia. MethodsA cross-sectional design was conducted to collect water samples in the water supply distribution networks of Addis Ababa, Ethiopia. Twenty-one (21) sampling stations yielded a total of one hundred twenty (120) samples of drinking water. The sample handling and collection procedures were carried out in accordance with USEPA guidelines. A DB-5 capillary column was used to separate the THMs, which were detected using GC-ECD (gas chromatography-electron capture detector). Spectrophotometric and in situ methods were used for physicochemical parameters. Redundancy analysis (RDA) was used for data analysis of trihalomethanes and environmental variables using CANOCO 4.5. ResultsThe mean concentration of total trihalomethanes in drinking water in Addis Ababa was 76.3 μg/L. The concentration of chloroform in the drinking water supply in Addis Ababa, Ethiopia, ranged between 4.03 and 79.4 μg/L. The mean total THMs in the Legedadi and Gefersa water supply systems were 77.4 μg/L and 69.66 μg/L, respectively. The residual chlorine, phosphates, UV absorbance at 254 nm, and combined chlorine had positive correlations with THM formation. However, electron conductivity had a negative correlation with THM formation. ConclusionsChloroform contributed the most to TTHMs in nearly all samples. The residual chlorine, UV absorbance, phosphate and hardness as calcium, and electron conductivity were found to be the main predictors determining the abundance and distribution of trihalomethanes. The monitoring and regulation of the THMs is required on a regular basis to analyse trends and guide the water treatment and distribution system.

Particle Size Regulation of Single-Crystalline Covalent Organic Frameworks for High Performance of Gas Chromatography.

Although polycrystalline covalent organic frameworks (PCOFs) have already shown great potential as stationary phases for chromatography, irregular shape and size distribution of PCOFs make regulation of particle size of PCOFs for high separation performance impossible, which is accessible by the application of single-crystalline COFs (SCOFs). Herein, we showed preparation of three-dimensional SCOF (SCOF-303) bonded capillaries (SCOF-303-capillary) with different particle sizes (about 0.4-1.6 μm) and further investigated gas chromatographic separation ability of these SCOF-303-capillaries for isomers of xylene, dichlorobenzene, and pinene. It was found resolution and column efficiency of SCOF-303-capillaries for isomers decreased with the increase in particle size, mainly resulting from the weaker size-exclusion effect and higher mass transfer resistance of the larger particle size of flexible SCOF-303. The obtained SCOF-303-capillary (particle size of ∼0.4 μm) offered baseline separation of xylene isomers with the high resolution of 2.26-3.52, great efficiency of 7879 plates m-1 for p-xylene, better than PCOF-303-capillary, and commercial DB-5 and HP-FFAP capillary columns as well as many reported capillaries. This work not only shows the great potential of SCOFs for gas chromatography but also provides the theoretical direction for the design of the efficient COF based stationary phase by adjusting the particle sizes.

Exposure and carcinogenic risk assessment of trihalomethanes (THMs) for water supply consumers in Addis Ababa, Ethiopia.

Trihalomethanes (THMs), a class of DBPs (disinfection byproducts) that includes chloroform, bromodichloromethane (BDCM), chlorodibromomethane (CDBM), and bromoform. To the best of authors' knowledge, no study has addressed the relationship between the concentration of THMs and lifetime cancer risks (LCR) in drinking water supply system in Addis Ababa, Ethiopia. Therefore, this study aimed to determine the lifetime cancer risks of exposure to THMs in Addis Ababa, Ethiopia. A total of 120 duplicate water samples were collected from 21 sampling points in Addis Ababa, Ethiopia. The THMs were separated by a DB-5 capillary column and detected by an electron capture detector (ECD). Cancer and non-cancer risk assessments were performed. The average total THMs (TTHMs)concentration in Addis Ababa, Ethiopia, was 76.3μg/L. Chloroform was the most dominant THM species identified. The total cancer risk for males was higher than that for females. The average LCR for TTHMs via ingestion in drinking water in this study was unacceptably high risk . An average LCR through dermal routes was also of unacceptably high risk . The LCR by chloroform contributes the highest (72%) of the total risk, followed by BDCM (14%), DBCM (10%) and bromoform (4%). The cancer risk of drinking water due to THMs in Addis Ababa was higher than the level recommended by the USEPA. The total LCR from the targeted THMs was higher via the three exposure routes. Males were at higher THM cancer risk than females. The hazard index (HI) indicated that the dermal route caused higher HI values than the ingestion route. It is essential to apply alternatives to chlorine, i.e., chlorine dioxide (ClO2), ozone and ultraviolet radiation, in Addis Ababa, Ethiopia. The monitoring and regulation of the THMs is required on a regular basis to analyse the trends and guide the water treatment and distribution system. The datasets generated for this analysis are available from the corresponding author upon reasonable request.

Determination of Methoxyacetic acid in urine by pre-column derivatization-liquid-liquid microextraction coupled with gas chromatography

Objective: To establish a method for determining methoxyacetic acid in urine by pre-column derivatization-liquid-liquid microextraction coupled with gas chromatography (GC) . Methods: Phosphate buffer solution, tert-butoxyacetic acid (internal standard) and pentafluorobenzyl bromide (derivative) were added to the urine sample. After derived in a water bath at 90 ℃ for 40 min, the mixture was cooled and filtered, then the dichloromethane was used as an extractant. After being shaken and centrifuged, the lower organic phase was sucked and injected into a gas chromatograph, separated by a DB-5 capillary column, and detected by an ECD detector. Results: The linear range of the method was 0.6~60.0 mg/L with the correlation coefficients (r) above 0.999. The average recovery was76.6%~110.7%, the inter-day precision was 8.00%~8.82%, and the detection limit was 0.13 mg/L. Conclusion: The method was founded to be high sensitivity, low organic reagent usage and green. So it is suitable for the detection of methoxyacetic acid in urine of occupational exposure to ethylene glycol monomethyl ether.

Membrane sampling for the determination of chlorothalonil in the air of workplaces-solvent analysis-Gas Chromatography

Objective: To establish a method for the determination of chlorothalonil in air by filtration membrane sampling, solvent elution and gas chromatography. Methods: PTFE filter was used for sampling, eluted with dichloromethane, separated by DB-5 capillary column, and determined by FID. Results: The standard curve was used for quantitative detection, and the correlation of chlorothalonil in the range of 15 μg/ml-300 μg/ml, R(2)=0.9999. The detection limit of this method was 1.70 μg/ml and the lower quantitative limit was 5.70 μg/ml. The minimum detected concentration was 0.045 mg/m(3) (75L air sample was collected) . The recovery rate was 90.14%-91.81%. The precision of the same batch was 1.5%-1.8%, and that of different batches was 2.3%-3.8%. The sampling efficiency can reach above 95%; The samples can be stored for 14 days at room temperature. Conclusion: The results show that the method of filtration membrane sampling-solvent elude-gas chromatography is suitable for the determination of chlorothalonil in the air.

GC-MS/O for the characterization of odours from cheese-production wastewater: A case study.

The foul odour of cheese-production wastewater is a common problem in areas surrounding dairy wastewater treatment plants. For successful odour management, a better understanding of the key odorants and how to handle them during wastewater treatment is needed. This paper documents the results of using gas chromatography-mass spectrometry coupled with olfactometry (GC-MS/O) to analyze odours emanating from a possibly overloaded treatment plant in Czechia. Using a DB5 capillary column, 20 compounds were detected and identified, nonanal (FDgeomean 152) and octen-3-ol (FDgeomean 2048) having the most pungent odours.

Residue analysis of fungicide boscalid in cucumbers following applications of boscalid 50% water dispersible granule

This study determined the residue of fungicide boscalid in/on cucumbers following three applications of boscalid 50% water dispersible granule (WG). The fungicide was applied to cucumbers at two rates, 0.5 and 0.83 kg a.i./ha. Samples were collected at 0, 1, 2, 3, 4, 6, 7, 10, 12, 15, 18, and 21 d after the last application. The sample was extracted with methanol/H2O/2 N HCl (70:25:5, v/v) and n-hexane and subject to GC analysis. Residues of boscalid were determined by GC/μ-ECD with DB-5 capillary column. Recoveries of boscalid in/on cucumbers ranged from 86.0 to 103.6% and the relative standard deviation (RSD) ranged from 1.2 to 4.8%. The limit of quantification was 0.01 μg/mL (S/N>10). This analytical method was applied to study the dissipation of boscalid in/on cucumbers. The results indicated that the residues of boscalid were declined in/on cucumbers with time. Only 5 and 17% of the initial deposits were found in/on the cucumbers 6 d after the last application at the low and high dose, respectively.

Analytical Methods for the Determination of Dialifos Residue in Agricultural Products

A method using gas chromatography (GC) was developed to determine insecticide dialifos in agricultural products. Dialifos were extracted with acetone, the filtrate was evaporated to 50 mL and mixed with 50 mL of petroleum ether; the mixture was then extracted with dichlormathane twice. The extracts were evaporated to dry, dissolved in acetone, and then determined by gas chromatography equipped with a flame photometric detector (FPD) and a DB-1 capillary column. Recovery studies were carried out by spiking the standard dialifos at the levels of 0.05∼0.15, 0.5∼1.5 and 0.5∼1.5 ppm to rice, citrus fruit and kiwi fruit, respectively. Average recoveries were 88.5∼93.4%, 94.4∼97.0% and 93.0∼99.7% and the detection limits were 0.01, 0.05 and 0.05 ppm, respectively. No residue of dialifos was detected in agricultural products which were sampled from traditional markets.

Determination of 1-methoxy-2-propanol in urine by headspace solid-phase microextraction coupled with gas chromatography

Objective: To establish a method for the determination of 1-methoxy-2-propanol in urine using headspace solid phase micro-extraction coupled with gas chromatography. Methods: The 1-methoxy-2-propanol was enriched by headspace solid phase micro-extraction fiber coated with carbene/polydimethylsiloxane (CAR/PDMS) . Single factor rotation method was used to optimize the conditions of extraction temperature, salt amount, and extraction time. The separation was performed on DB-5 (30 m×0.32 mm×0.25 μm) capillary column and detected with flame ionization detector. The quantification was based on the standard curve. Results: The concentration of 1-methoxy-2-propanol in urine was linear in the range of 0.50-10.0 mg/L, and the linear correlation coefficient was 0.9993. The detection limit of the method was 0.14 mg/L, and the limit of quantification was 0.45 mg/L. The recovery was 85.8% to 104.7%, and the RSD of intra- and inter-batch precision were 3.25%-6.65% and 0.81%-3.96%, respectively. Conclusion: The method is high sensitivity and simple operation, and is suitable for the determination of 1-methoxy-2-propanol in urine of occupational exposure population.

Determination of Sevoflurane, Isoflurane and Enflurane in the air of workplace by gas chromatography

Objective: To establish a solvent desorption gas chromatographic method for determination of Sevoflurane, Isoflurane and Enflurane in the air of the Workplace. Methods: Sevoflurane, Isoflurane and Enflurane were collected with activated carbon tube and desorbed with dichloromethane, separated with DB-1 capillary columns, and then detected with flame ionization detector. Results: The linearity ranges were 1.9-304.8 μg/ml for Sevoflurane, 2.1-300.4 μg/ml for Isoflurane and 1.7-305.2 μg/ml for Enflurane, The correlation coefficient was both >0.999. Their limits of detection were 0.6 μg/ml, 0.6 μg/ml and 0.5 μg/ml, and Their limits of quatification were 1.9 μg/ml, 2.1 μg/ml and 1.7 μg/ml, and their minimum detectable concentrations were 0.1、0.2 and 0.1 mg/m(3) per 4.5 L of air. Their relative standard deviations (RSD) were 2.5%-3.0%, 2.3%-3.1% and 2.2%-3.0%. The average desorption efficiencies were 101.1%-103.3%, 100.7%-102.7% and 101.0%-102.9%. The sampling efficiency was both 100%. The breakthrough volume of 100 mg actived carbon was 3.7 mg, 3.4 mg and 3.4 mg. Sevoflurane, Isoflurane and Enflurane in activated carbon tube could be kept at least 10 days at room temperature without significant losses. Conclusion: The method shows lower detection limit, high accuracy and precision. It is feasible for determination of Sevoflurane, Isoflurane and Enflurane in the air of workplace.

Method development for the identification and quantitative analysis of seven nitrosamines using gas chromatography mass spectrometry

Abstract Nitrosamines (NAms) are emerging organic pollutants formed as by-products of chemical treatment of water, environmental samples as well as in foods at low concentrations. They are potentially carcinogenic and because of their hydrophilic and volatile nature, they are highly soluble in water. They fragment at high temperatures thus, they require appropriate oven temperature and gas flow rate in gas chromatography mass spectrometry (GC-MS) for their quantitative analysis. The analytical method for the identification and quantitation of seven volatile and thermally un-stable nitrosamines namely, (N-nitrosodimethylamine (NDMA), N-nitrosomethylethylamine (NMEA) N-nitrosodiethylamine (NDEA), N-nitrosopyrrolidine (NPYR), N-nitrosodi-n-propylamine (NDPA), N-nitrosopiperidine (NPIP) and N-nitrosodi-n-butylamine (NDBA) is presented in this work. The GC-MS with a DB-5 (30 m × 0.25 mm × 0.25 µm) capillary column (5% phenyl-95% dimethyl polysiloxane) was used in selective ion monitoring (SIM) mode. The target and reference ions ranged between 70–114 and 41–57 correspondingly, produced accurate mass measurement and sharper and clearly defined chromatogram. The relative standard deviation, RSD

Correlation between the key aroma compounds and gDNA copies of Bacillus during fermentation and maturation of natto

The aim of the study was to analyze the correlation between the key aroma compounds and gDNA copies of Bacillus natto during fermentation and maturation of natto. Solvent-assisted flavor evaporation (SAFE) techniques were employed to extract volatile organic compounds. Aroma compounds were separated and analyzed through gas chromatography-olfactometry-mass spectrometry (GC-MS/O) using DB-5 and DB-Wax capillary columns. Seventy-nine compounds were extracted and identified, including 17 ketones, 17 alcohols, 9 aldehydes, 6 acids, 7 esters, 8 pyrazines, 8 aromatics, and 7 others. Twenty-two compounds were identified as the key aroma compounds of natto by aroma extraction dilution analysis (AEDA). Pyrazines played a key role in the flavor of natto both during the fermentation and maturation. 2,5-Dimethylpyrazine, 2,3,5-trimethylpyrazine, 2,3,5,6-tetramethylpyrazine, and 2,3,5-methyl-6-ethylpyrazine contributed substantially to natto flavor. They presented significant positive and negative correlations with the gDNA copies of Bacillus natto during fermentation and maturation, respectively.

Comparison of SPME Versus SAFE Processes for the Analysis of Flavor Compounds in Watermelon Juice

The aim of the study was to compare the extraction efficiency of headspace and solvent extraction methods on watermelon juice flavor. Solid-phase microextraction (SPME) and solvent-assisted flavor evaporation (SAFE) techniques were employed to extract the volatiles from watermelon juice. Aroma compounds were separated and analyzed through gas chromatography-olfactometry-mass spectrometry (GC-MS/O) equipped with DB-5 and DB-Wax capillary columns. Forty-seven compounds were identified by SPME (30) and SAFE (28). These compounds included 7 aldehydes, 10 olefinic aldehydes, 14 alcohols, 7 sulfur compounds, 5 ketones, and 4 miscellaneous compounds. SPME extracted the saturated aldehydes, olefinic aldehydes, alcohols, and ketones effectively, whereas SAFE exerted better efficiency to extract sulfur compounds. (Z,Z)-3,6-Nonadienal, (Z)-6-nonen-1-ol, (E)-2-hexenal, (E)-2-nonenal, hexanal, nonanal, (Z)-3-nonen-1-ol, and (E)-2-octenal were identified as the key aroma compounds through odor activity value (OAV) and aroma extract dilution analysis (AEDA). Also, the aroma compounds can be extracted comprehensively by the combination of both SPME and SAFE techniques.

A Simple Method for Monitoring Eight N-Nitrosamines in Beef Jerkys by Gas Chromatography–Tandem Mass Spectrometry with One-Step Treatment Coupled to Active Carbon Solid-Phase Extraction

A simple method was developed for monitoring eight N-nitrosamines (N-nitrosodimethylamine, N-nitrosomethylethylamine, N-nitrosodiethylamine, N-nitrosodipropylamine, N-nitrosomorpholine, N-nitrosopiperidine, N-nitrosopyrrolidine, and N-nitrosodibutylamine) in beef jerkys by gas chromatography–tandem mass spectrometry with one-step treatment coupled to active carbon solid-phase extraction. Sample was first treated with barium hydroxide solution, and then the sample solution is cleaned and concentrated using a Sep-Pak AC-2 cartridge. Chromatographic separation was achieved on a DB-1701 capillary column, and mass spectrometry was performed with electron-impact ionization and multiple reaction monitoring. Good linear ranges were obtained for eight analytes in the range of 1–200 ng mL−1 with the coefficient (R 2) higher than 0.999. Limit of detection and limit of quantitation were in ranges of 0.05–0.10 and 0.10–0.30 ng g−1, respectively; at 0.3, 3.0, and 10 ng g−1 spiking levels, the recoveries were 70.1–121.5% with the relative standard deviations at 3.4–17.8%. Comparing with the traditional methods, the merits of the new method are simple, relative procedure and environment-friendly, easy to use, and suitable for routine screening or analyzing samples in batch.

Catalytic Oxidation of Vanillyl Alcohol Using FeMCM-41 Nanoporous Tubular Reactor

Iron containing nanoporous MCM-41 (FeMCM-41) with different Si/Fe ratios of 50, 100 and 150 was synthesized by hydrothermal synthesis process. The materials obtained from hydrothermal synthesis were characterized by various physico chemical techniques such as XRD, N2 adsorption, DR UV-vis, EPR and FTIR spectroscopy. XRD analyses of FeMCM-41 materials confirmed the presence of well-ordered crystalline structure. N2 isotherm of FeMCM-41 materials showed type IV adsorption isotherm. EPR and DR UV-vis analysis of FeMCM-41 samples indicates the presence of high tetrahedral coordination at the Si/Fe ratios of 100 and 150. The catalytic performance of FeMCM-41 nano tubular reactor was tested in the liquid phase oxidation of vanillyl alcohol into vanillin using H2O2 (50[Formula: see text]wt% in water). The reaction products were analyzed by gas chromatography in DB-5 capillary column with flame ionization detector. The products were confirmed by 1H NMR, [Formula: see text]C NMR and LC-Mass spectroscopy. The maximum conversion of vanillyl alcohol (85%) and selectivity towards vanillin (82%) were observed using the catalyst FeMCM-41(100) in 30[Formula: see text]min at 60[Formula: see text]C. The influence of reaction temperature, reaction time, reactants molar ratio, Si/Fe ratio and amount of catalyst were investigated.

Comparison of Four Extraction Methods, SPME, DHS, SAFE, Versus SDE, for the Analysis of Flavor Compounds in Natto

Natto is a kind of traditional fermentation food. Organic soybean of china northeast was selected as the material to produce natto according to the condition optimized before. Four extraction methods (SAFE (solvent-assisted flavor evaporation), SDE (simultaneous distillation and extraction), SPME (solid phase microextraction), and DHS (dynamic headspace sampling)) were applied to extract the volatile compounds of natto. Aroma compounds were separated and analyzed with gas chromatography-olfactometry-mass spectrometry (GC-MS/O) of DB-5 and DB-Wax capillary columns. Seventy-seven compounds were identified by four extraction methods. Among them, 42, 23, 31, and 36 compounds were identified by SPME, DHS, SDE, and SAFE, respectively. SAFE and SDE had a better extraction effect on ester, ether, and aromatic compounds, while SPME and DHS could extract ketone, acid, and pyrazine compounds effectively. SPME was fit for the extraction of natto aroma compounds. These compounds included 14 ketones, 9 alcohols, 4 aldehydes, 6 acids, 4 sulfur compounds, 5 esters, 8 pyrazines, 19 aromatics, and 8 others. Fourteen compounds were identified as key aroma compounds in natto, including 2,3-butanedione, 5-methyl-2-hexanone, 3-hydroxy-2-butanone, 2-nonanone, furaldehyde, acetic acid, 2-ethyl butyric acid, ethyl acetate, 2,5-dimethylpyrazine, 2,3,5-trimethylpyrazine, 3,5-dimethyl-2-ethylpyrazine, 2,3,5,6-tetramethylpyrazine, 2,3,5-methyl-6-ethylpyrazine, and benzaldehyde. Pyrazine was the important aroma compound with the high FD (flavor dilution) value in natto.

Compositional and Enantiomeric Analysis of the Essential Oil of Taxodium Distichum from India

The leaf essential oil composition of Taxodium distichum L., collected from the foothills of Uttarakhand, India was analyzed using gas chromatography-flame ionization detection (GC-FID) and gas chromatography-mass spectrometry (GC-MS) equipped with DB-5 (5% diphenyl-95% dimethyl polysiloxane) and β-cyclodextrin (6-tertiarybutyldimethylsiliyl-2,3-diethyl-β-cyclodextrin) capillary columns. Seventeen constituents, representing 90.3 to 99.4% of composition were identified in the essential oils from different seasons, viz. spring, summer, rainy, autumn and winter. The essential oil composition was mainly dominated by monoterpene hydrocarbons, represented mainly by α-pinene (81.9-94.3%). Other constituents of the oil were myrcene (0.5-4.7%), β-pinene (2.2-2.9%), limonene (0.5-1.5%), camphene (≤ 0.03-1.5%), and α-terpineol (upto 1.6%). Chiral analysis of T. distichum essential oil on an ethyl substituted β-cyclodextrin capillary column revealed the presence of a-pinene in racemic form, with an enantiomeric ratio of 49.3% for (1R)-(+)- and 50.7% for (1S)-(-)-α-pinene.

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.

Residue and Risk Assessment of Kresoxim-methyl in Apple Under Field Conditions

A rapid and effective method was developed for determination of kresoxim-methyl residue in apple. Field trials were designed to evaluate the dissipation and residue of kresoxim-methyl in apple at Hebei (China), Shandong (China) and Anhui (China). The dietary exposure and risk assessment were also conducted by using the calculation of risk quotient (RQ). The samples were extracted by Acetone and ethyl acetate, cleaned up by Florisil solid phase extraction column and detected by gas chromatograph with DB-1701 capillary column and electron capture detector. The results showed good average recoveries of 80%-99% with relative standard deviations of 0.9%-1.3% at the spiked level of 0.02, 0.20 and 2.0 mg /kg. The limit of detection (LOD) was 1.0×10-12 g and the limit of quantification (LOQ) was 0.02 mg /kg. The results were found that the half lives of kresoxim-methly in apple of Hebei (China), Shandong (China) and Anhui (China) were 6.09, 12.6 and 10.0 d respectively, and the terminal residue was below MRL (0.2 mg/kg) 14 days after application, the RQ of kresoxim-methyl were far below 1. It predicted that it was safe for human being when kresoxim-methyl was used to control Apple tree diseases.