Rapid determination of methanol in black liquors by full evaporation headspace gas chromatography

This paper reported a full evaporation headspace gas chromatographic (GC) technique for determination of methanol content in black liquors (pulping spent liquor). In this method, a very small volume (10-20 microL) of liquor sample is introduced into a headspace sample vial (20 mL) and heated up to a temperature of 105 degrees C. A near-complete mass transfer of methanol from the liquid phase to vapor phase (headspace), i.e., a full evaporation, can be achieved within 3 min. The methanol in the headspace of the vial is then measured by GC. The present method is simple, rapid and accurate.     

Rapid determination of furfural in biomass hydrolysate by full evaporation headspace gas chromatography

This paper reports a full evaporation (FE) headspace gas chromatographic (HS-GC) method for rapid determination of furfural in the biomass hydrolysate. The data show that a near-complete mass transfer of furfural in the sample from biomass hydrolysate to the vapor phase (headspace) was achieved within 3 min at 105°C when a very small (<40 μL) sample was added to a 20 mL headspace sample vial. The acid-catalyzed furfural decomposition under these conditions was negligible. The furfural in the vapor phase was then determined by HS-GC using a flame ionization detector. The results showed that the method has an excellent measurement precision (RSD<0.5%) and accuracy (recovery=100.2±1.7%) for furfural quantification in carbohydrate hydrolysate samples. The method requires no sample pretreatment, so it is simple, rapid and accurate, and suitable for applications in lignocellulosic biomass conversion to fuel ethanol or other high value-added products.     

Determination of polycyclic aromatic hydrocarbons in aqueous samples by microwave assisted headspace solid-phase microextraction and gas chromatography/flame ionization detection

The novel pretreatment technique, microwave-assisted heating coupled to headspace solid-phase microextraction (MA-HS-SPME) has been studied for one-step in situ sample preparation for polycyclic aromatic hydrocarbons (PAHs) in aqueous samples before gas chromatography/flame ionization detection (GC/FID). The PAHs evaporated into headspace with the water by microwave irradiation, and absorbed directly on a SPME fiber in the headspace. After being desorbed from the SPME fiber in the GC injection port, PAHs were analyzed by GC/FID. Parameters affecting extraction efficiency, such as SPME fiber coating, adsorption temperature, microwave power and irradiation time, and desorption conditions were investigated.Experimental results indicated that extraction of 20 mL aqueous sample containing PAHs at optional pH, by microwave irradiation with effective power 145 W for 30 min (the same as the extraction time), and collection with a 65 μm PDMS/DVB fiber at 20 °C circular cooling water to control sampling temperature, resulted in the best extraction efficiency. Optimum desorption of PAHs from the SPME fiber in the GC hot injection port was achieved at 290 °C for 5 min. The method was developed using spiked water sample such as field water with a range of 0.1-200 μg/L PAHs. Detection limits varied from 0.03 to 1.0 μg/L for different PAHs based on S/N = 3 and the relative standard deviations for repeatability were <13%. A real sample was collected from the scrubber water of an incineration system. PAHs of two to three rings were measured with concentrations varied from 0.35 to 7.53 μg/L. Recovery was more than 88% and R.S.D. was less than 17%. The proposed method is a simple, rapid, and organic solvent-free procedure for determination of PAHs in wastewater.     

Determination of residual monomer in polymer latex by full evaporation headspace gas chromatography

This study demonstrated a full evaporation (FE) headspace gas chromatographic technique for the determination of residual monomer in methyl methacrylate (MMA) polymer latex. A very small amount (approximately 10-30 mg) of latex was added to a sealed headspace sample vial (20 ml). A near-complete monomer mass transfer from both liquid (aqueous phase) and solid phase (polymer particles) to the vapor phase (headspace) is achieved within 5 min at a temperature of 110 degrees C. The method eliminates sample pretreatment procedures such as the solvent extraction. Thus, it avoids the risk of polymer deposition on the GC system caused by a directly injection of extraction solvent in the conventional GC monomer analysis. The present method is simple, rapid, and accurate.     

Analysis of aqueous pyrethroid residuals by one-step microwave-assisted headspace solid-phase microextraction and gas chromatography with electron capture detection

A one-step microwave-assisted headspace solid-phase microextraction (MA-HS-SPME) has been applied to be a pretreatment step in the analysis of aqueous pyrethroid residuals by gas chromatography (GC) with electron capture detection (ECD). Microwave heating was applied to accelerate the vaporization of pyrethroids (bioallenthrin, bifenthrin, fenpropathrin, cyhalothrin, permethrin, cyfluthrin, cypermethrin, fluvalinate, fenvalerate and deltamethrin) into the headspace, and then being absorbed directly on a SPME fiber under the controlled conditions. Optimal conditions for the SPME sampling, such as the selection of sampling fiber, sample pH, sampling temperature and time, microwave irradiation power, desorption temperature and time were investigated and then applied to real sample analysis. Experimental results indicated that the extraction of pyrethroids from a 20-mL aquatic sample (pH 4.0) was achieved with the best efficiency through the use of a 100-μm PDMS fiber, microwave irradiation of 157 W and sampling at 30 °C for 10 min. Under optimum conditions, the detections were linear in the range of 0.05-0.5 μg/L with the square of correlation coefficients (R²) of >0.9913 for pyrethroids except bifenthrin being 0.9812. Method detection limits (MDL) were found to be varied from 0.2 to 2.6 ng/L for different pyrethroids based on S/N (signal to noise) = 3. The coefficients of variation (CVs) for repeatability were 7-21%. A field underground water sample was analyzed with recovery between 88.5% to 115.5%. This method was proven to be a very simple, rapid, and solvent-free process to achieve the sample pretreatment before the analysis of trace pyrethroids in aqueous samples by gas chromatography.     

Use of headspace mulberry paper bag micro solid phase extraction for characterization of volatile aromas of essential oils from Bulgarian rose and Provence lavender

In this study, a new sampling method called headspace mulberry paper bag micro solid phase extraction (HS-MPB-μ-SPE) combined to gas chromatography-mass spectrometry has been applied for the analysis of volatile aromas of liquid essential oils from Bulgarian rose and Provence lavender. The technique uses an adsorbent (Tenax TA) contained in a mulberry paper bag, minimal amount of organic solvent. Linearities for the six-points calibration curves were excellent. LOD values were in the rage from 0.38 ng mL⁻¹ to 0.77 ng mL⁻¹. Overall, precision and recovery were generally good. Phenethyl alcohol and citronellol were the main components in the essential oil from Bulgarian rose. Linalyl acetate and linalool were the most abundant components in the essential oils from true lavender or lavandin. Additionally, the relative extraction efficiencies of proposed method have been compared with HS-SPME. The overall extraction efficiency was evaluated by the relative concentration factors (CF) of the several characteristic components. CF values by HS-MPB-μ-SPE were lower than those by headspace solid phase microextraction (HS-SPME). The HS-MPB-μ-SPE method is very simple to use, inexpensive, rapid, requires small sample amounts and solvent consumption. In addition, this method allowed combining of extraction, enrichment, and clean-up in a single step. HS-MPB-μ-SPE and GC/MS is a promising technique for the characterization of volatile aroma compounds from liquid essential oils.     

Determination of glucose and ethanol after enzymatic hydrolysis and fermentation of biomass using Raman spectroscopy

Raman spectroscopy has been used for the quantitative determination of the conversion efficiency at each step in the production of ethanol from biomass. The method requires little sample preparation; therefore, it is suitable for screening large numbers of biomass samples and reaction conditions in a complex sample matrix. Dilute acid or ammonia-pretreated corn stover was used as a model biomass for these studies. Ammonia pretreatment was suitable for subsequent measurements with Raman spectroscopy, but dilute acid-pretreated corn stover generated a large background signal that surpassed the Raman signal. The background signal is attributed to lignin, which remains in the plant tissue after dilute acid pretreatment. A commercial enzyme mixture was used for the enzymatic hydrolysis of corn stover, and glucose levels were measured with a dispersive 785 nm Raman spectrometer. The glucose detection limit in hydrolysis liquor by Raman spectroscopy was 8 g L⁻¹. The mean hydrolysis efficiency for three replicate measurements obtained with Raman spectroscopy (86 ± 4%) was compared to the result obtained using an enzymatic reaction with UV-vis spectrophotometry detection (78 ± 8%). The results indicate good accuracy, as determined using a Student's t-test, and better precision for the Raman spectroscopy measurement relative to the enzymatic detection assay. The detection of glucose in hydrolysis broth by Raman spectroscopy showed no spectral interference, provided the sample was filtered to remove insoluble cellulose prior to analysis. The hydrolysate was further subjected to fermentation to yield ethanol. The detection limit for ethanol in fermentation broth by Raman spectroscopy was found to be 6 g L⁻¹. Comparison of the fermentation efficiencies measured by Raman spectroscopy (80 ± 10%) and gas chromatrography-mass spectrometry (87 ± 9%) were statistically the same. The work demonstrates the utility of Raman spectroscopy for screening the entire conversion process to generate lignocellulosic ethanol.     

Extraction and determination of organophosphorus pesticides in water samples by a new liquid phase microextraction-gas chromatography-flame photometric detection

A rapid, sensitive and efficient liquid phase microextraction (LPME) method was developed to determine trace concentrations of some organophosphorus pesticides in water samples. This method combines liquid phase microextraction with gas chromatographic (GC) analysis in a simple and inexpensive apparatus involving very little organic solvent consumption. It involves exposing a floated drop of an organic solvent on the surface of aqueous solution in a sealed vial. Experimental parameters which control the performance of LPME such as type of organic solvent, organic solvent and sample volumes, sample stirring rate, sample solution temperature, salt addition and exposure time were investigated and optimized. Finally, the enrichment factor, dynamic linear range (DLR), limit of detection (LOD) and precision of the method were evaluated by the water samples spiked with organophosphorus pesticides. Using optimum extraction conditions, very low detection limits (0.01-0.04 μg L⁻¹) and good linearities (0.9983 < r² < 0.9999) were achieved. The LPME was performed for determination of organophosphorus pesticides in different types of natural water samples and acceptable recoveries (96-104%) and precisions (3.5 < R.S.D.% < 8.9) were obtained. The results suggested that the newly proposed LPME method is a rapid, accurate and effective sample preparation method and could be successfully applied for extraction and determination of organophosphorus pesticides in water samples.     

Rapid removal of selected volatile organic compounds from gaseous mixtures using a new dispersive vapor extraction technique: A feasibility study

A new dispersive vapor extraction (DVE) technique for rapid removal of selected volatile organic compounds (VOCs) from gaseous mixtures was investigated. In this technique, less than 1.0 mL of a volatile solvent was vaporized for 8 min in a 250-mL flask containing a gaseous mixture. The flask was then cooled under running tap water for 2-3 min to induce condensation of the vapor and co-extraction of the VOCs from the headspace. The technique was tested over a concentration range of 4-23 ppb, and resulted in extraction efficiencies ranging from 80 to 97% for the VOCs tested. Because of its simplicity and the relatively short sampling time, DVE could potentially lead to high sample throughput and rapid air analysis.     

Programmed temperature vaporizer based method for the sensitive determination of trihalomethanes and benzene,toluene, ethylbenzene and xylenes in soils

A methodology based on the coupling of a headspace autosampler with a GC and a MS detector operating in SIM mode has been developed for the determination of volatile organic compounds (THMs and BTEX) in soils. The GC device used is equipped with a programmable temperature vaporizer (PTV) packed with Tenax-TA^® to introduce the samples (the injection mode used was solvent vent), and a modular accelerated column heater (MACH™) to control column temperature. The proposed measurement procedure reduces the sample pretreatment step to a minimum. Combined use of solvent vent injection mode and mass spectrometry detection allows a highly sensitive method to be proposed, with limits of detection of the order of ng/kg for all the target compounds. Furthermore, the capillary column used allows rapid separations of compounds in less than 4.60 min, affording a very short total analysis cycle time of 9 min.     

Determination of the residual ethanol in hydroalcoholic sealed hard gelatin capsules by static headspace gas chromatography with immiscible binary solvents

Static headspace gas chromatography (HS-GC) with immiscible binary solvents is described to quantitatively determine the residual ethanol used to seal the hard gelatin capsules by liquid encapsulated and microspray sealing (LEMS; cfs 1200, Greenwood, SC, USA). The effects of decane, dodecane, heptane, 0.1 M HCl, N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidinone and dimethyl sulfoxide on the method sensitivity are compared. It is observed that the ethanol headspace concentrations can be increased by fourfolds when aliphatic hydrocarbon solvents are added into the aqueous sample solutions in a HS vial. In addition, a mathematic model based on the concentration equilibriums of liquid–liquid and liquid–gas phases is derived to quantitatively describe the ethanol headspace concentrations versus the volumes of the aliphatic hydrocarbon solvents. The proposed model fits well to the experimental data. The impacts of the oven temperatures and vial equilibration times on the ethanol headspace concentrations are also investigated. Furthermore, the potential interferences of the capsule placebo and hard gelatin capsule shells on the selectivity and quantitation of the method are discussed. The linearity is validated from 5 μg/mL to 500 μg/mL. The limit of quantitation is 5 μg/mL. The accuracy is determined to be 100.8 ± 6%. Finally, this method is successfully used to determine the residual ethanol in the sealed capsules of 5 mg and 10 mg developmental Drug A, and 100 mg and 200 mg developmental Drug B.     

Headspace solid-phase microextraction of phthalic acid esters from vegetable oil employing solvent based matrix modification

A new solvent-free analytical procedure based on headspace solid-phase microextraction (SPME) coupled to gas chromatography employing an electron capture detector (GC/ECD) or alternatively a mass spectrometric detector (GC/MSD) has been developed for the determination of phthalic acid esters (dimethyl-[DMP], diethyl-[DEP], di-n-butyl-[DnBP], butylbenzyl-[BBP], di-2-ethylhexyl-[DEHP] and di-n-octyl [DnOP] phthalate) in vegetable oils. Four different fiber coatings were evaluated, among them polydimethylsiloxane with a thickness of 100 μm appeared to be the best choice for allowing extraction of the whole group of analytes. Various solvents were tested as sample matrix modification agents with the aim to facilitate the transfer of esters with low vapour pressure (DEHP and DnOP) from oil matrix into the headspace. The addition of methanol resulted in optimal set-up applicable for all phthalate esters. Temperature control and the way of sample stirring were recognized as critical points of the whole procedure. Primarily, because shaking rather than stirring of the sample is carried out using a CombiPal multipurpose sampler, the automation of the SPME method employing this instrument was found to be not fully suitable for efficient stripping of phthalates from the oil matrix into the sample headspace. Nevertheless, the optimized manual SPME method, encompassing GC/ECD or GC/MSD for the separation and detection of target analytes, offers a unique solution and showed acceptable performance characteristics: linear response in the range of 0.5-2 mg kg⁻¹ and repeatability expressed as R.S.D. between 14 and 23% at the spiking level of 2 mg kg⁻¹.     

Field analysis of benzene, toluene, ethylbenzene and xylene in water by portable gas chromatography-microflame ionization detector combined with headspace solid-phase microextraction

In this work, portable gas chromatography-microflame ionization detection (portable GC-μFID) coupled to headspace solid-phase microextraction (HS-SPME) was developed for the field analysis of benzene, toluene, ethylbenzene and xylene (BTEX) in water samples. The HS-SPME parameters such as fiber coating, extraction times, stirring rate, the ratio of headspace volume to sample volume, and sodium chloride concentration were studied. A 65 μm poly(dimethylsiloxane)-divinylbenzene (PDMS-DVB) SPME fiber, 900 rpm, 3.0 ml of headspace (1.0 ml water sample in 4.0 ml vial), and 35% sodium chloride concentration (w/v) were respectively chosen for the best extraction response. An extraction time of 1.0 min was enough to extract BTEX in water samples. The relative standard deviation (R.S.D.) for the procedure varied from 5.4% to 8.3%. The method detection limits (MDLs) found were lower than 1.5 μg/l, which was enough sensitive to detect the BTEX in water samples. The optimized method was applied to the field analysis of BTEX in wastewater samples. These experiment results show that portable GC-μFID combined with HS-SPME is a rapid, simple and effective tool for field analysis of BTEX in water samples.     

Gas flow headspace liquid phase microextraction

There is a trend towards the use of enrichment techniques such as microextraction in the analysis of trace chemicals. Based on the theory of ideal gases, theory of gas chromatography and the original headspace liquid phase microextraction (HS-LPME) technique, a simple gas flow headspace liquid phase microextraction (GF-HS-LPME) technique has been developed, where the extracting gas phase volume is increased using a gas flow. The system is an open system, where an inert gas containing the target compounds flows continuously through a special gas outlet channel (D = 1.8 mm), and the target compounds are trapped on a solvent microdrop (2.4 μL) hanging on the microsyringe tip, as a result, a high enrichment factor is obtained. The parameters affecting the enrichment factor, such as the gas flow rate, the position of the microdrop, the diameter of the gas outlet channel, the temperatures of the extracting solvent and of the sample, and the extraction time, were systematically optimized for four types of polycyclic aromatic hydrocarbons. The results were compared with results obtained from HS-LPME. Under the optimized conditions (where the extraction time and the volume of the extracting sample vial were fixed at 20 min and 10 mL, respectively), detection limits (S/N = 3) were approximately a factor of 4 lower than those for the original HS-LPME technique. The method was validated by comparison of the GF-HS-LPME and HS-LPME techniques using data for PAHs from environmental sediment samples.     

Headspace solvent microextraction: a very rapid method for identification of volatile components of Iranian Pimpinella anisum seed

At the present study, a new and rapid headspace solvent microextraction (HSME), for the extraction and pre-concentration of the volatile components of plant sample into a microdrop was applied. The extraction occurred by suspending a microliter drop of the solvent from the tip of a microsyringe to the headspace of a ripen and powdered dry fruit sample (Iranian Pimpinella anisum seed) in a sealed vial for a preset extraction time, then the microdrop was retracted back into the microsyringe and injected directly into a GC injection port. The chemical composition of the HSME extracts were confirmed according to their retention indexes and mass spectra (EI, 70 eV); and quantitative analysis was performed by GC-FID.Parameters such as the nature of the extracting solvent, particle size of the sample, temperatures of the microdrop and sample, volume of sample and the extraction time were studied and optimized, and the method's performance was evaluated. The optimized conditions were: sample particle size, 1 mm; sample volume, 5 ml (in a 15 ml vial); sample temperature, 60 °C; microsyringe needle temperature, 0 °C; and extraction time, 10 min. Finally, accordingly, the percentage of trans-anethole (the major compound of P. anisum) and the relative standard deviation for extraction and determination of trans-anethole (seven-replicated analysis) were determined to be 90% and 3.9%, respectively.     

Solid phase microextraction/gas chromatography/mass spectrometry integrated with chemometrics for detection of Salmonella typhimurium contamination in a packaged fresh vegetable

A rapid method for detection of Salmonella typhimurium contamination in packaged alfalfa sprouts using solid phase microextraction/gas chromatography/mass spectrometry (SPME/GC/MS) integrated with chemometrics was investigated. Alfalfa sprouts were inoculated with S. typhimurium, packed into commercial LDPE bags and stored at 10 + 2 °C for 0, 1, 2 and 3 days. Uninoculated sprouts were used as control samples. A SPME device was used to collect the volatiles from the headspace above the samples and the volatiles were identified using GC/MS. Chemometric techniques including linear discriminant analysis (LDA) and artificial neural network (ANN) were used as data processing tools. Numbers of Salmonella were followed using a colony counting method. From LDA, it was able to differentiate control samples from sprouts contaminated with S. typhimurium. The potential to predict the number of contaminated S. typhimurium from the SPME/GC/MS data was investigated using multilayer perceptron (MLP) neural network with back propagation training. The MLP comprised an input layer, one hidden layer, and an output layer, with a hyperbolic tangent sigmoidal transfer function in the hidden layer and a linear transfer function in the output layer. The MLP neural network with a back propagation algorithm could predict number of S. typhimurium in unknown samples using the volatile fingerprints. Good prediction was found as measured by a regression coefficient (R² = 0.99) between actual and predicted data.     

Determination of ammonium in aqueous samples using new headspace dynamic in-syringe liquid-phase microextraction with in situ derivitazation coupled with liquid chromatography–fluorescence detection

A new simultaneous derivatization and extraction method for the preconcentration of ammonia using new one-step headspace dynamic in-syringe liquid-phase microextraction with in situ derivatization was developed for the trace determination of ammonium in aqueous samples by liquid chromatography with fluorescence detection (LC–FLD). The acceptor phase (as derivatization reagent) containing o-phthaldehyde and sodium sulfite was held within a syringe barrel and immersed in the headspace of sample container. The gaseous ammonia from the alkalized aqueous sample formed a stable isoindole derivative with the acceptor phase inside the syringe barrel through the reciprocated movements of plunger. After derivatization-cum-extraction, the acceptor phase was directly injected into LC–FLD for analysis. Parameters affecting the ammonia evolution and the extraction/derivatization efficiency such as sample matrix, pH, temperature, sampling time, and the composition of derivatization reagent, reaction temperature, and frequency of reciprocated plunger, were studied thoroughly. Results indicated that the maximum extraction efficiency was obtained by using 100 μL derivatization reagent in a 1-mL gastight syringe under 8 reciprocated movements of plunger per min to extract ammonia evolved from a 20 mL alkalized aqueous solution at 70 °C (preheated 4 min) with 380 rpm stirring for 8 min. The detection was linear in the concentration range of 0.625–10 μM with the correlation coefficient of 0.9967 and detection limit of 0.33 μM (5.6 ng mL⁻¹) based on S N⁻¹ = 3. The method was applied successfully to determine ammonium in real water samples without any prior cleanup of the samples, and has been proved to be a simple, sensitive, efficient and cost-effective procedure for trace ammonium determination in aqueous samples.     

In-line coupling headspace liquid-phase microextraction with capillary electrophoresis

An analytical technique of in-line coupling headspace liquid-phase microextraction (HS-LPME) with capillary electrophoresis (CE) was proposed to determine volatile analytes. A special cover unit of the sample vial was adopted in the coupling method. To evaluate the proposed method, phenols were used as model analytes. The parameters affecting the extraction efficiency were investigated, including the configuration of acceptor phase, kind and concentration of acceptor solution, extraction temperature and time, salt-out effect, sample volume, etc. The optimal enrichment factors of HS-LPME were obtained with the sample volume of about half of sample vials, which were confirmed by both the theoretical prediction and experimental results. The enrichment factors were obtained from 520 to 1270. The limits of detection (LODs, S/N = 3) were in the range from 0.5 to 1 ng/mL each phenol. The recoveries were from 87.2% to 92.7% and the relative standard deviations (RSDs) were lower than 5.7% (n = 6). The proposed method was successfully applied to the quantitative analysis of the phenols in tap water, and proved to be a simple, convenient and reliable sample preconcentration and determination method for volatile analytes in water samples.     

Determination of aniline in silica gel sorbent by one-step in situ microwave-assisted desorption coupled to headspace solid-phase microextraction and GC-FID

Microwave-assisted desorption (MAD) coupled to in situ headspace solid-phase microextraction (HS-SPME) was first proposed as a possible alternative pretreatment of samples in absorbent collected from workplace monitoring. Aniline collected on silica gel was investigated. Under microwave irradiation, the aniline was desorbed from silica gel and directly absorbed onto the SPME fiber in the headspace. Having been sampled on the SPME fiber, and desorbed in the GC injection port, aniline was analyzed using a GC-FID system. Parameters that affect the proposed extraction efficiency, including the extraction media and its pH, the microwave irradiation power and the irradiation time as well as desorption parameters of the GC injector, were investigated. Experimental results revealed that the extraction of a 150-mg silica gel sample using a 0.8-ml aqueous solution (pH 12) and a PDMS/DVB fiber under medium-high-powered irradiation (345 W) for 3 min maximized the efficiency of extraction. Desorption of aniline from the SPME fiber was optimal at 230 °C held for 3 min. The detection limit was 0.09 ng. The proposed method provided a simple, fast, and organic solvent-free procedure to analyze aniline from a silica gel matrix.     

Analysis of hexachlorocyclohexanes in aquatic samples by one-step microwave-assisted headspace controlled-temperature liquid-phase microextraction and gas chromatography with electron capture detection

A microwave-assisted headspace controlled-temperature liquid-phase microextraction (HS-CT-LPME) technique was applied for the one-step sample extraction of hexachlorocyclohexanes (HCHs) from aqueous samples with complicate matrices, followed by gas chromatographic (GC) analysis with electron capture detector (ECD). Microwave heating was applied to accelerate the evaporation of HCHs into the headspace and an external-cooling system was used to control the temperature in the sampling zone for HS-LPME. Parameters affecting extraction efficiency, such as LPME solvent, sampling position and temperature, microwave power and irradiation time (the same as sampling time), sample pH, and salt addition were thoroughly investigated. From experimental results, the following conditions were selected for the extraction of HCHs from 10-mL water sample (pH 2.0) by using 1-octanol as the LPME solvent, with sampling done at 38 °C for 6 min under 167 W of microwave irradiation. The detections were linear in the concentration of 0.1–10 μg/L for α-HCH and γ-HCH, and 1–100 μg/L for β-HCH and δ-HCH. Detection limits were 0.05, 0.4, 0.03 and 0.1 μg/L for α-, β-, γ- and δ-HCH, respectively. Environmental water samples were analyzed with recovery between 86.4% and 102.4% for farm-field water, and between 92.2% and 98.6% for river water. The proposed method proved to serve as a simple, rapid, sensitive, inexpensive, and eco-friendly procedure for the determination of HCHs in aqueous samples.