Phase Extraction-gas Chromatography-mass Spectrometry Research Articles

Postharvest dehydration of red grapes: impact of temperature and water-loss conditions on free and glycosylated volatile metabolites of exocarp and epicarp of Nebbiolo and Aleatico varieties.

Postharvest dehydration affects the metabolism of grapes, impacting odorous secondary metabolites and therefore the features of the corresponding passito wines - high-quality products with winemaking practices linked to specific territories and related autochthonous grape varieties. Water loss and temperature conditions are the main variables of the dehydration process. This study assessed how they impacted the patterns of free and glycosylated volatile organic compounds (VOCs) of the exocarp (pulp) and epicarp (skin) in Nebbiolo and Aleatico, a neutral and semi-aromatic red grape variety, respectively. Dehydration parameters were set in tunnel conditions, and VOCs were quantitatively analyzed by solid phase extraction-gas chromatography-mass spectrometry. For Nebbiolo grapes, weight loss had a greater impact on free volatiles than dehydration temperature, with a 20% weight loss increasing total VOCs in both exocarp and epicarp. Low temperature (10 °C) significantly increased (P < 0.05) the glycosylated VOCs' terpene content. In Aleatico grapes, weight loss was key in modulating free volatiles, with 30% weight loss and 15 °C leading to significant increases in VOCs, especially exocarp terpenes, acids and benzenoids. More stressful dehydration (30% weight loss at 25 °C) resulted in higher aroma precursor concentrations. These findings can assist passito wine production in preserving varietal aromas of original grapes trough optimized dehydration conditions, preventing sensory homologation occurring because of strong uncontrolled dehydration. They can also promote optimization of energy consumption, thus fostering financial and environmental sustainability. © 2024 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

An automated micro solid phase extraction gas chromatography–mass spectrometry (μSPE-GC–MS) detection method for geosmin and 2-methylisoborneol in drinking water

Geosmin and 2-methylisoborneol (2-MIB) are amongst the most common earthy and musty taste and odour (T&O) compounds found in drinking water. With low odour threshold detection limits below 10 ng L−1, and the complexity of raw water matrices, these two compounds provide a significant challenge for water companies globally. In this research, for the first time, a novel and fully automated micro-solid phase-extraction (μSPE) method coupled with gas chromatography (GC)–mass spectrometry (MS) has been developed for the detection of geosmin and 2-MIB for drinking water analysis. The new automated method described herein is environmentally friendly requiring low raw water sample volumes, of 25 mL, and only 50 μL of elution solvent. Our μSPE-GC–MS method exhibits excellent linearity for both compounds (R2 > 0.999) and low limits of detection of 2.0 ng L−1 and 4.3 ng L−1 for geosmin and 2-MIB, respectively. The method showed excellent recovery rates (95.1–100.1%) and good precision (RSD < 7%) in raw sample matrices. Our approach is fully automated onto a robotic workstation which can be readily integrated into a laboratory workflow for routine water analysis. Furthermore, the method has excellent potential to be incorporated within a portable system for onsite analysis.

Migration of volatile substances from recycled high density polyethylene to milk products

Plastic recycling is the main solution to reduce the plastic waste. High-density polyethylene has not been recycled yet successfully as food contact material due to the amount of chemicals present in post-consumer material together with its high chemical sorption capacity. The migration of two post-consumer recycled HDPE milk bottles were studied to both 50 % ethanol as food simulant and real food (one type skimmed milk and two plant base beverages (soy milk and horchata). Firstly, a headspace-solid phase extraction-gas chromatography mass spectrometry method was developed and optimized to analyze these milky samples. After exposure, 53 compounds were identified and among them several additives, NIAS such as 2,5-cyclohexadiene-1,4-dione, 2,6-bis(1,1-dimethylethyl), 2,4-di-tert-butylphenol and 7,9-di-tert-butyl-1-oxaspiro(4,5)deca-6,9-diene-2,8-dione, degradation products of antioxidant compounds as well as several residues from cleaning products, detergents and flavoring agents were found. Finally, the risk assessment was applied and it was found that five compounds did not comply after migration to 50 % ethanol.

Characterization of Berry Aromatic Profile of cv. Trebbiano Romagnolo Grapes and Effects of Intercropping with Salvia officinalis L.

Volatile organic compounds (VOCs) are secondary metabolites responsible for the aroma of grapes and the quality of wine. Apart from genetics, agronomic practices may impact the aroma composition and the concentration of volatiles in grape berries. The possible influence of intercropping with medicinal aromatic plants (MAPs) on the VOCs in grape berries’ profile has been poorly explored. Trebbiano Romagnolo is a white Vitis vinifera cultivar cultivated within the Italia region Emilia-Romagna. The study investigated, for the first time, the volatile organic profile of Trebbiano Romagnolo berries as well as the possible influences of intercropping with sage (Salvia officinalis L.) on the volatile composition of grape berries. A total of 48 free and bound aroma compounds were identified using solid phase extraction-gas chromatography-mass spectrometry (SPE-GC-MS). In the free aroma fraction, the main classes were C6 derivatives, alcohols, and benzenes, while in the bound aroma fraction, the major classes were benzenes, C13 norisoprenoids, and terpenes. The results obtained in this experiment indicate that intercropping with Salvia officinalis may influence volatile compounds in grape berries, an interesting result in cultivars considered neutral such as Trebbiano Romagnolo, providing new insights for exploring the complexity of the terroir and the role of agroecological strategies.

Removal of organic pollutants by effluent recirculation constructed wetlands system treating landfill leachate

The leachate of municipal solid waste landfills contains various types of organic substances, increasing the difficulty of efficient treatment. This study built an effluent recirculation (1:4 ratios) vertical subsurface flow constructed wetlands (CWs) system treating actual landfill leachate (LL). In order to better monitor and evaluate the removal of organic pollutants in LL by CWs, Three-Dimensional Fluorescence (3D-EEM) and Solid Phase Extraction–Gas Chromatography–Mass Spectrometry (SPE–GC–MS) analysis of CWs influent and effluent water was performed to investigate the removal of Dissolved organic matter (DOM), Organochlorine pesticides (OCPs), Organophosphorus pesticide (OPPs), Polycyclic aromatic hydrocarbons (PAHs), and Volatile organic compounds (VOCs). Results showed that during the treatment of LL by CWs, the average removal rate of conventional pollutants (COD, NH4+-N and TP) was over 85%, with a majority of microbial metabolites and humic acids in DOM effectively degraded. The concentrations of OCPs, OPPs, PAHs, and VOCs in the CWs influent LL ranged between 378.6 and 4746.32 ng L−1, accounting for only a small proportion (3.7×10−7–4.6×10−6) of COD. The achieved organic micro-pollutants total removal rates were: OCPs(56.9%), OPPs(41.4%), PAHs(58.3%), and VOCs(78.3%), with relatively higher removal rates observed for DDT (83.6%), dimethoate (89.2%), benzo(a)anthracene (82.0%). Therefore, the effluent recirculation CWs system can effectively remove organic pollutants in LL, indicating that this is a promising technology with good application for the effective treatment of wastewater.

Study on the method of detection of benzene exposure biomarkers by solid phase extraction-gas chromatography-tandem mass spectrometry

Objective: A gas chromatography-tandem mass spectrometry detection method for benzene and its metabolites was established to provide methodological support and theoretical basis for the study of benzene toxicity mechanism. Methods: In August 2019 to March 2020, the animal model of containing high concentration of benzene by inhalation of poison through the respiratory tract of mice was established, taken the blood of mice after dyeing the poison, and the HLB solid phase extraction method was used to extract and purify the samples. The gas chromatography-tandem mass spectrometry detection method was used to qualitative and quantitative analysis of the target substances. After separated by HP-17MS capillary chromatographic column, the compounds were ionized with EI ion source, mass spectrometry detection was carried out by selective ion scanning method (SIM) , and quantification was carried out by external standard curve method. Results: Benzene and its metabolites (phenol, catechol, hydroquinone and m-trihydroxybenzene) in blood could be effectively separated and quasi deterministic and quantitative by this method. The regression equations and correlation coefficients of this method for detecting benzene and its metabolites were: benzene: y=3252.1x+1540, r=0.9993; phenol: y=2046.5x+1423, r=0.9991; catechol: y=1853.9x+945, r=0.9993; hydroquinone: y=1891.5x+840, r=0.9992; m-trihydroxybenzene: y=1052.4x+655, r=0.9991. The detection limits for benzene, phenol, catechol, hydroquinone and m-trihydroxybenzene were 0.03, 0.03, 0.05, 0.05 and 0.10 μg/g, respectively. And the lower limits of quantification were 0.10, 0.10, 0.15, 0.15 and 0.30 μg/g, respectively. The intra-assay precision interval was 2.64%-10.06%, the inter-assay precision interval was 1.37%-10.17%, and the spike recovery rate was 89.8%-102.3%. This method could be used to quantitatively detect benzene, phenol, catechol, hydroquinone and m-trihydroxybenzene in the blood of benzene-infected mice. Conclusion: Solid phase extraction-gas chromatography-mass spectrometry can be used for qualitative and quantitative detection of benzene and its metabolites (phenol, catechol, hydroquinone and m-trihydroxybenzene) accurately.

Effect of 1–20 years storage on volatiles and aroma of Keemun congou black tea by solvent extraction-solid phase extraction-gas chromatography-mass spectrometry

Keemun congou black tea (KCBT), a kind of tea suitable for storage, its aroma changes considerably during storage. In this study, seven same grade KCBTs, that had been stored for 1–20 years, were analyzed, solvent extraction-solid phase extraction-gas chromatography-mass spectrometry (SE-SPE-GC-MS) was used to analyze volatiles changes. The effect of storage on volatiles was strong, dozens of volatiles varied and had potential to be indicators of storage. In the first category of volatiles, the concentrations fluctuated and then decreased, a clear line of demarcation mostly existed between the 5th and 10th years. In the second category, the concentrations exponentially decreased with a high coefficient of determination (R2) during the entire storage, most of these volatiles were crucial glycoside-derived volatiles, including geraniol, linalool, etc. In the third category, the concentrations increased and then decreased, most of these volatiles were products of the autoxidation of lipids and carotenoids—with hexanoic acid and dihydroactinidiolide being representative examples, respectively. These volatiles were outstanding storage markers for the first 5 years of storage. In the final category, the concentrations continually increased, methoxy benzenes volatiles including 1,2,3-trimethoxybenzene, 1,2,4-trimethoxybenzene etc., were representative and favorable indicators of KCBT being stored for more than 5 years.

Qualitative and Quantitative Analysis of Cathinones in Human Urine by SPE-GC-MS.

To propose an alternative solid phase extraction-gas chromatography-mass spectrometry （SPE-GC-MS） method for the sensitive determination of cathinones in human urine samples, plus methodological verification. Human urine samples were concentrated by solid phase extraction （SPE） sorbent and converted into the corresponding heptafluorobutyric acid anhydride derivatives. Methcathinone, 4-methylmethcathinone and 3,4-methylenedioxy-N-methylcathinone were detected by gas chromatography-mass spectrometry （GC-MS）. With quantitative analysis by internal standard method, methodological verification was carried out from the aspects of specificity, precision and reco-very rate. Methcathinone, 4-methylmethcathinone and 3,4-methylenedioxy-N-methylcathinone showed good linearly in the range of 25-200 ng/mL of urine （r>0.99）, with the limits of detection 2.0 ng/mL, limit of quantitation 25.0 ng/mL, both intra- and inter-day coefficients of variation lower than 6.0%, and recovery rates of 98.4%-105.7%. he proposed SPE-GC-MS procedure has good accuracy and specificity, can meet the need of qualitative and quantitative analysis of cathinones in the urine of drug abusers, and therefore provide technical support for the detection of cathinone abuse.

Direct detection of Mycobacterium tuberculosis in sputum: A validation study using solid phase extraction-gas chromatography-mass spectrometry.

Tuberculosis (TB) remains a worldwide health problem, especially in developing countries. Correct identification of Mycobacterium tuberculosis (MTB) infection is extremely important for providing appropriate treatment and care to patients. Here we describe a solid phase extraction-gas chromatography-mass spectrometry method (SPE-THM-GC-MS) for the detection of five biomarkers for M. tuberculosis. The method for classification is developed and validated through the analysis of 112 sputum samples from patients suspected of having TB. Twenty of twenty-five MTB culture-positive sputum samples were correctly classified as positive by our improved SPE-THM-GC-MS method. Eighty-five of eighty-seven MTB culture-negative samples were also negative by SPE-THM-GC-MS. The overall sensitivity of the new SPE-THM-GC-MS method is 80% (20/25) and the specificity is 98% (85/87) compared with culture. The method proved to be reliable and, although complex in principle, easy to operate due to the high degree of automation.

A modified commercial gas chromatograph for the continuous monitoring of the thermal degradation of sunflower oil and off-line solid phase extraction gas–chromatography–mass spectrometry characterization of released volatiles

A homemade flow cell attached to a commercial Gas Chromatograph equipped with a Flame Ionization Detector (FID) has been designed for the continuous monitoring of volatile compounds released during heating edible oils. Analytical parameters such as mass of sample, temperature and flow rates have been optimized and the obtained results have been compared with the corresponding thermographs from standard TG systems. Results show that under optimum conditions, the profiles of volatiles released upon heating are comparable to the profiles of TG curves, suggesting that the FID based system could be an alternative to TGA. Additionally, volatiles have been retained in a Lichrolut EN® resin, eluted and analyzed by Gas Chromatography–Mass Spectrometry. In this case, forty five compounds have been identified (acids, alcohols, alkanes, aldehydes, ketones and furans) and compared with the FID signals, working both in air or nitrogen atmosphere. It has been concluded that the oxidative thermal degradation is prevented in the presence of a nitrogen atmosphere.

Direct detection of Mycobacterium tuberculosis in sputum using combined solid phase extraction-gas chromatography-mass spectrometry.

Recently, thermally-assisted hydrolysis and methylation followed by gas chromatography-mass spectrometry (THM-GC-MS) in combination with chemometrics has been used to develop a 20-compound model for fast differentiation of Mycobacterium tuberculosis (MTB) from Non-tuberculous mycobacteria (NTM) in bacterial cultures. This model provided better than 95% accuracy. In our current work a hexane/methanol/water extraction followed by a solid phase extraction (SPE) clean-up procedure was developed for use before THM-GC-MS, to make the test suitable for the identification of mycobacteria in sputum. The 20 biomarker model had to be adapted since many compounds were also found in the sputum of non-tuberculosis patients. An algorithm was established based on tuberculostearic acid, hexacosanoic acid and mycoserosates. The detection limit of the method was approximately 1×10(4) bacteria/mL sputum. Sputum specimens from 32 patients from South Africa who were suspected of having tuberculosis were blindly tested using the new method. Eight of the nine culture-positive sputum specimens were detected by the new SPE-THM-GC-MS method, resulting in a sensitivity of 89%. The specimen that was missed by the new method was also microscopy negative. The specificity of the test was 100%; all 23 microscopy- and culture-negative specimens were correctly identified as negative by SPE-THM-GC-MS.

Determination of plasticizer residues in tea by solid phase extraction–gas chromatography–mass spectrometry

Human exposure to plasticizers is widespread because these compounds are commonly found in the environment. Nevertheless, studies on human dietary exposure to plasticizers are limited. This research deals with the evaluation of 27 plasticizer residues in tea infusion samples brewed with and without bag. Levels were determined by solid phase extraction–gas chromatography–mass spectrometry (SPE–GC–MS). Only a small number of plasticizer were detected: di(2-ethylhexyl) phthalate (DEHP), di-n-butyl phthalate (DBP) and DEP were found in all analyzed samples, while di-methyl phthalate (DMP), bis-(2-ethylhexyl) adipate (DEHA) and DiNP in 80, 70 and 10 % of them. Flavored teas showed higher DMP, DEHA and DEHP residues, probably due to the use of essential oils where plasticizers are accumulated. In addition, decaffeinated black tea showed DBP levels 18 times higher compared with the average of the other samples. The plasticizer contents in samples infused with bag was almost always higher than those infused without bag. The evaluation of contribution of infusion teas to phthalate exposure showed that these do not constitute a risk for the consumers.

Simultaneous determination of nine pharmaceuticals personal care products in waters by solid phase extraction-gas chromatography-mass spectrometry

An analytical method has been developed and validated for the simultaneous determination of nine pharmaceuticals and personal care products (PPCPs) in water samples, including salicylic acid, naproxen, ibuprofen, paracetamol, clofibric acid, triclosan, diclofenac, ketoprofen, bisphenol A. The qualification and quantification of the target compounds were performed by gas chromatography-mass spectrometry in selected ion monitoring mode (GC-MS-SIM). The water samples were concentrated and purified through Oasis HLB cartridges after the pH value of the water was adjusted to 3, then derivatized with trimethyl sulfonium hydroxide (TMSH) at room temperature, and determined by GC-MS-SIM using 2,4,5-fenoprop as internal standard. The conditions for sample pretreatment (e. g. solid phase extraction and derivatization) were studied. Under the optimized conditions, the recoveries were ranged from 50.7% to 115.4% with the relative standard deviations lower than 10%. The limits of detection were in the range of 0.03-0.30 microg/L and the limits of quantification were in the range of 0.15-1.50 microg/L. The method has been successfully applied to monitor the occurrence of the PPCPs residues in agricultural irrigation water in Dongguan, Guangdong Province. The four compounds were detected at maximum mass concentration range of 0.176-0.998 microg/L. It proved that this analytical method is sensitive, reliable and acceptable.

Simultaneous determination of 87 pesticides in river water and seawater using solid phase extraction-gas chromatography-mass spectrometry

A method for the simultaneous determination of 87 commonly used pesticides in China including 24 organophosphorous pesticides, 15 organochlorine pesticides, 12 azoles, 9 pyrethroids, 7 amides and anilines, 5 carbamates and other 15 pesticides in river water and seawater was established using solid phase extraction (SPE)-gas chromatography-mass spectrometry (GC-MS). GC-MS parameters influencing separation and sensitivity were optimized, and the effects of sample volume, pH and salinity on SPE were investigated. The purification was performed using NH2 SPE cartridge. An internal standard and 5 surrogates were used for data analysis and quality control. The results indicated that under the optimized conditions the limits of detection were in the range of 0.1 - 6.6 ng/L. For most target pesticides, recoveries were between 60% and 120% with relative standard deviations (RSDs, n = 4) of 0.01% - 9.7% at the spiked levels of 5 ng/L and 20 ng/L in real river water and sea water matrices. The method was successfully applied to monitor multi-class pesticides in surface water in Fujian Jiulong estuary, and 20 pesticides including 5 organophosphorous pesticides, 3 amides, 4 azoles, 3 carbamates, 2 pyrethroids and 3 other pesticides were detected in the mass concentration range of 1.18 - 660.93 ng/L. The proposed method can meet the requirement for the determination of trace pesticide residues in water samples.

Determination of cholesterol in drainage oil by solid phase extraction-gas chromatography-mass spectrometry

An effective method was developed for the determination of cholesterol in drainage oil by solid phase extraction-gas chromatography-mass spectrometry (SPE-GC-MS). Firstly, the samples were purified by SPE on a column packed with silica. An extraction yield of 97% was obtained when a 20 mL of ethyl ether/n-hexane mixture (0.6: 99.4, v/v) was used for washing the SPE column, and 10 mL of the same solvent mixture (15: 85, v/v) for desorbing cholesterol from the SPE column. Then the final extract was determined by GC-MS with electron impact ion source. The cholesterol was characterized according to retention time and characteristic fragments (m/z 213, 275, 301, 368, 386), and was quantitatively determined by external standard method in selected ion monitoring mode. The fragment of m/z 386 was selected as the target ion, and m/z 213 and m/z 275 were used as the reference ions. The average recovery was from 91.7% to 101%, and the relative standard deviations (RSDs) were below 6%, and the detection limit was 0.01 mg/L. A good linearity was obtained in the cholesterol concentration range of 0.24 - 6.0 mg/L with the correlation coefficient of 0.999 6. The proposed method can be used to determine the cholesterol content in oil accurately, and the detection result can be one of the criteria judging the existence of drainage oil in edible oil.

Determination method for 17 pesticides in common in whole blood by gas chromatography coupled to mass spectrometry with solid-phase extraction sample cleanup

To establish a method for simultaneous determination of 17 common pesticides in whole blood by solid phase extraction-gas chromatography-mass spectrometry (SPE-GC-MS). Whole blood samples were treated by extraction with acetonitrile, and the obtained extract was cleaned up using an Oasis HLB SPE cartridge; pesticides were separated by GC and quantitatively analyzed by MS with selected ion monitoring. The concentrations of 17 pesticides in whole blood were 1.0-5.0 mg/L, and the recovery rate was 41.3-102.1%, with a relative standard deviation of less than 10%in most pesticides. The 17 pesticides showed a good linear relationship between concentration and peak area within 0.5-5.0 mg/L, with a correlation coefficient of 0.9945-0.9994. The limit of detection and limit of quantification were 0.02-0.05 mg/L and 0.05-0.09 mg/L, respectively. With this method, 17 pesticides in whole blood can be well separated and determined. This method has high sensitivity, accuracy, and precision and can be used for identification and quantification of multiple pesticides in blood samples.

Determination of Halogenated Flame Retardants in Willow Bark by Solid Phase Extraction-Gas Chromatography-Mass Spectrometry

A solid phase extraction-gas chromatography-negative chemical ionization-mass spectrometric method was developed for the simultaneous determination of 2, 3, 5, 6-tetrabromo-P-xylene (pTBX), 1,2,3,4,5-pentabromobenzene (PBBz), Pentabromotoluene (PBT), 2, 3, 5, 5, 6-pentabromoethylbenzene (PBEB), Hexabromobenzene (HBB), sys-Dechlorane Plus (s-DP), anti-Dechlorane Plus (a-DP) and polybrominated diphenyl ethers (PBDEs). Willow bark samples were extracted with hexane-acetone (1: 1, V/V) for 24 h by Soxhlet extraction apparatus and cleaned with a silica/alumina column, which was eluted by hexane :dichloromethane (3 :7). Recoveries in the matrix ranged from 76.2% to 92.3%, and limits of detection were from 0.1 to 5.0 ng/g lipid. Recoveries of C-13(6)-HBB, C-13(12)-BDE-139 and C-13(10)-s-DP in the samples were 75.6% +/- 2.2%, 77.3% +/- 3.4% and 76.0% +/- 2.8%, respectively. pTBX, PBT, PBBz, HBB, s-DP, a-DP and PBDEs were detected in all bark samples, while the detection rate of PBEB was 16.7%.

Influencing factors and degradation products of antipyrine chlorination in water with free chlorine

Owing to its low cost, free chlorine is one of the most common disinfectants for wastewater and drinking water treatment. However, the formation of disinfection byproducts has been found to occur after free chlorine disinfection in recent decades. Antipyrine (ANT), an anti-inflammatory analgesic, has been frequently detected in the aquatic environment. In this work, the removal efficiency of ANT by free chlorine oxidation in ultrapure water was investigated with batch experiments. The influencing factors on the removal of ANT were explored at initial concentrations of ANT from 0.04 to 0.64 mg/L, free chlorine dosage from 0.30 to 1.31 mg/L, and pH from 1.5 to 9.0. The main degradation products were identified by solid phase extraction-gas chromatography-mass spectrometry. The results showed that ANT reacted rapidly with free chlorine in ultrapure water systems and up to 90.6% removal efficiency of ANT was achieved after 25 sec (initial free chlorine 1 mg/L, ANT 0.5 mg/L, pH 7.0). Higher oxidant dosage, lower ANT initial concentration and low pH favor the ANT removal. The main degradation product in ANT chlorination was a monochlorine substitution product (4-chloro-1,2-dihydro-1,5-dimethyl-2-phenyl-3H-pyrazol-3-one), which can be further chlorinated by free chlorine. In addition, the total organic carbon result indicated that ANT is difficult to be mineralized using chlorine.

Determination of 17 Phthalic Acid Esters in Fatty Food by Dispersive Solid Phase Extraction-Gas Chromatography-Mass Spectrometry

A method was developed for the determination of 17 phthalic acid esters in fatty food by dispersive solid phase extraction-gas chromatography-mass spectrometry(d-SPE-GC-MS).Tea milk samples were extracted with acetonitrile: methyl tert-butyl ether(9 ∶ 1,V/V),and the extract was cleaned up by MAS-PAEC d-SPE column.Flavor seasonings samples were extracted with acetonitrile(saturated with hexane): methyl tert-butyl ether(19 ∶ 1,V/V),and the extract was cleaned up by CNW d-SPE column.Matrix-match external standard method was used for quantification.The results showed that the average recoveries of 17 phthalic acid esters in milk tea were 82.2%-125.4% and relative standard deviations were less than 16.5%.The limit of detection(LOD) of all the compounds were 100-200 μg/kg.The average recoveries of 17 phthalic acid esters in flavor seasonings were 70.9%-115.5% and relative standard deviations were less than 9.8%.The limits of detection(LOD) of all the compounds were 400-800 μg/kg.The method is quick,sensitive,easy,cheap,rugged,and can be applied to the detection of 17 phthalic acid esters in fatty food.

Determination of organophosphorus pesticides in peanut oil by dispersive solid phase extraction gas chromatography–mass spectrometry

The organophosphorus pesticides including phorate, diazinon, tolclofos-methyl, fenitrothin, malathion, fenthion, isocarbophos, quinalphos and phenamiphos, in peanut oils were determined by liquid–liquid extraction coupled with dispersive solid phase extraction and gas chromatography–mass spectrometry (GC–MS). The mixture of multi-walled carbon nanotubes and alumina was used as adsorbent in dispersive solid phase extraction. The effects of some experimental conditions, such as types of multi-walled carbon nanotubes, amount of adsorbents and extraction time were examined. The limits of detection for the analytes were between 0.7 and 1.6 μg kg −1. The obtained recoveries of the analytes in the samples were between 85.9 and 114.3% and relative standard deviations were lower than 8.48%.