Study on the preparation of CdS/TiO2 corn straw biochar composite materials for photocatalytic reduction of CO2 and collaborative H2 production.

A thermal synthesis method was employed in this work to prepare CdS/TiO2 corn straw biochar photocatalytic composite materials suitable for synergistic hydrogen production with the photocatalytic reduction of CO2. The structure and synergistic reaction of these composite materials were characterized by its photogenerated electron transfer process. Compared with pure TiO2, the energy band gap of the optimal CdS/TiO2 corn straw biochar composite material was reduced to 2.89 eV. The heterostructure coupling between TiO2 and CdS in the biochar accelerated the transfer of photogenerated electrons and reduced the recombination rate of photogenerated electrons and holes. Under visible light irradiation, the photocatalytic H2 yield of this CdS/TiO2 corn straw-derived biochar composite material was 1200 µmol·h-1·g-1, the CO yield was 150 µmol·h-1·g-1, and the CH4 yield was 55 µmol·h-1·g-1. The key to this synergistic reaction is the formation of heterojunctions between CdS and TiO2 as well as the rapid oxidation of holes in the composite material caused by the doping of biochar.

TransCrack: revisiting fine-grained road crack detection with a transformer design.

Prior convolution-based road crack detectors typically learn more abstract visual representation with increasing receptive field via an encoder-decoder architecture. Despite the promising accuracy, progressive spatial resolution reduction causes semantic feature blurring, leading to coarse and incontiguous distress detection. To these ends, an alternative sequence-to-sequence perspective with a transformer network termed TransCrack is introduced for road crack detection. Specifically, an image is decomposed into a grid of fixed-size crack patches, which is flattened with position embedding into a sequence. We further propose a pure transformer-based encoder with multi-head reduced self-attention modules and feed-forward networks for explicitly modelling long-range dependencies from the sequential input in a global receptive field. More importantly, a simple decoder with cross-layer aggregation architecture is developed to incorporate global with local attentions across different regions for detailed feature recovery and pixel-wise crack mask prediction. Empirical studies are conducted on three publicly available damage detection benchmarks. The proposed TransCrack achieves a state-of-the-art performance over all counterparts by a substantialmargin, and qualitative results further demonstrate its superiority in contiguous crack recognition and fine-grained profile extraction. This article is part of the theme issue 'Artificial intelligence in failure analysis of transportation infrastructure and materials'.

3D-DFM: Anchor-Free Multimodal 3-D Object Detection With Dynamic Fusion Module for Autonomous Driving.

Recent advances in cross-modal 3D object detection rely heavily on anchor-based methods, and however, intractable anchor parameter tuning and computationally expensive postprocessing severely impede an embedded system application, such as autonomous driving. In this work, we develop an anchor-free architecture for efficient camera-light detection and ranging (LiDAR) 3D object detection. To highlight the effect of foreground information from different modalities, we propose a dynamic fusion module (DFM) to adaptively interact images with point features via learnable filters. In addition, the 3D distance intersection-over-union (3D-DIoU) loss is explicitly formulated as a supervision signal for 3D-oriented box regression and optimization. We integrate these components into an end-to-end multimodal 3D detector termed 3D-DFM. Comprehensive experimental results on the widely used KITTI dataset demonstrate the superiority and universality of 3D-DFM architecture, with competitive detection accuracy and real-time inference speed. To the best of our knowledge, this is the first work that incorporates an anchor-free pipeline with multimodal 3D object detection.

Supercritical water oxidation of p-aminonaphthalenesulfonic acid and enhancement by Fenton agent.

The introduction of Fe2+ into supercritical water oxidation (SCWO) and the formation of Fenton reagent with oxidant H2O2 form a new environment, namely, supercritical Fenton oxidation (SCFO) environment. p-Aminonaphthalenesulfonic acid was selected as the typical organic pollutant to explore the effects of temperature, oxidant multiple, reaction time and Fenton conditions on the TOC removal rate. SCFO showed the superiority in the degradation of organic matter compared with the SCWO. The oxidative degradation kinetics of p-aminonaphthalenesulfonic acid in SCFO environment was further explored. Under SCFO condition, the oxidative degradation of p-aminonaphthalene sulfonic acid was consistent with first-order reaction kinetics. The results showed that the activation energy Ea and pre exponential factor k 0 were 39.937 kJ·mol-1 and 1.94 × 104 s-1 respectively.

[Pollution Levels, Sources, and Spatial Distribution of Phthalate Esters in Soils of the West Lake Scenic Area].

To investigate pollution from phthalate esters (PAEs) in the soils of the West Lake Scenic Area, Hangzhou, Zhejiang province, a total of 42 samples were collected from 4 species of soil with different uses. The concentrations and composition of 6 PAEs were analyzed by gas chromatography triple quadrupole mass spectrometry (GC-MS/MS). The sources and spatial distribution of PAEs in the different soil species were analyzed using Principal Component Analysis (PCA) and Ordinary Kriging (OK) methods. It was found that the total concentrations of the 6 PAEs (ΣPAEs) ranged from 597.6 µg·kg-1 to 7360.1 µg·kg-1, of which Dimethyl Phthalate (DMP), Di-n-buthyl Phthalate (DBP), and Di-(2-ethylhexyl) Phthalate (DEHP) were most abundant (98.43% of ΣPAEs). As major pollutant, DEHP contributed as much as 66.28% to ΣPAEs. The composition of PAEs in different soil species differed due to source differences; transportation and tourist activities were the main sources of these PAEs. The 6 PAEs were mainly distributed in the northwestern portion of the West Lake Scenic Area, decreasing from north to south and from east to west.

Fenton's reagent-enhanced supercritical water oxidation of wastewater released from 3-hydroxypyridine production.

A study on Fenton's reagent-enhanced supercritical water oxidation (SCFO) of wastewater released from 3-hydroxypyridine production was carried out in this paper. The effects of temperature, oxidant multiple, residence time, Fe2+ concentration, and pH on the degradation efficiency of wastewater were investigated. The Plackett-Burman test was designed to evaluate various factors, namely, temperature, oxidant multiple, and pH, which were found to significantly affect degradation efficiency. Response surface analysis was performed to optimize the parameter levels of the main influencing factors. The results indicated that the optimal conditions required for the oxidative degradation of wastewater in the SCFO systems were pH of 3, temperature of 473 °C, oxidant multiple of 7, Fe2+ concentration of 0.5 mg L-1, and residence time of 262.6 s (flow rate: 1.5 mL min-1). Under these conditions, the total organic carbon removal rate of the wastewater could reach 98.1%. The activation energy of the wastewater under SCFO conditions was 55.3 kJ mol-1, and the pre-exponential factor A was 52.8 s-1.

Enantioseparation of chiral mandelic acid derivatives by supercritical fluid chromatography.

Mandelic acid and its derivatives are important chiral analogs which are widely used in the pharmaceutical synthetic industry. The present study investigated the enantiomeric separation of six mandelic acids (mandelic acid, 2-chloromandelic acid, 3-chloromandelic acid, 4-chloromandelic acid, 4-bromomandelic acid, 4-methoxymandelic acid) on the Chiralpak AD-3 column by supercritical fluid chromatography. The influences of volume fraction of trifluoroacetic acid, type and percentage of modifier, column temperature, and backpressure on the separation efficiency were investigated. And the enantiomer elution order was determined. The results show that, for a given modifier, the retention factor, the separation factor, and the separation resolution decreased gradually with increasing the volume ratio of the modifier. At the same volume ratio of modifier, the retention factor of the mandelic acid and its derivatives increased in the order of methanol, ethanol, and isopropanol, except 3-chloromandelic acid. The separation factor and the separation resolution decreased with the increase of column temperature (below the temperature limit). The backpressure affected the enantioseparation process: As the backpressure increased, a corresponding decrease in retention factor was observed. Under the same chiral column conditions, the SFC method exhibited faster and more efficient separation with better enantioselectivity than the HPLC method.

Early life exposure of zebrafish (Danio rerio) to synthetic pyrethroids and their metabolites: a comparison of phenotypic and behavioral indicators and gene expression involved in the HPT axis and innate immune system.

Ecotoxicological studies have revealed the association between synthetic pyrethroid (SP) exposure and aquatic toxicity in fish; however, research on the toxic effects of SP metabolites is still limited. In this study, the toxicity of two SPs (permethrin (PM) and ß-cypermethrin (ß-CP)) and their three metabolites (3-phenoxybenzoic alcohol (PBCOH), 3-phenoxybenzaldehyde (PBCHO), and 3-phenoxybenzoic acid (PBCOOH)) towards zebrafish embryos and larvae was evaluated. Both SPs and their metabolites exhibited significant developmental toxicities, caused abnormal vascular development, and changed locomotor activities in larvae. The alteration of gene expression involved in the thyroid system and the innate immune system indicated that SPs and their three metabolites have the potency to induce thyroid disruption and trigger an immune response. The results from the present study suggest that SP metabolites could induce multiple toxic responses similar to parent compounds, and their toxicity should be considered for improving the understanding of environmental risks of SPs.

Enantiomeric separation of six chiral pesticides that contain chiral sulfur/phosphorus atoms by supercritical fluid chromatography.

Six chiral pesticides containing chiral sulfur/phosphorus atoms were separated by supercritical fluid chromatography with supercritical CO2 as the main mobile phase component. The effect of the chiral stationary phase, different type and concentration of modifiers, column temperature, and backpressure on the separation efficiency was investigated to obtain the appropriate separation condition. Five chiral pesticides (isofenphos-methyl, isocarbophos, flufiprole, fipronil, and ethiprole) were baseline separated under experimental conditions, while isofenphos only obtained partial separation. The Chiralpak AD-3 column showed a better chiral separation ability than others for chiral pesticides containing chiral sulfur/phosphorus atoms. When different modifiers at the same concentration were used, the retention factor of pesticides except flufiprole decreased in the order of isopropanol, ethanol, methanol; meanwhile, the retention factor of flufiprole increased in the order of isopropanol, ethanol, methanol. For a given modifier, the retention factor and resolution decreased on the whole with the increase of its concentration. The enantiomer separation of five chiral pesticides was an "enthalpy-driven" process, and the separation factor decreased as the temperature increased. The backpressure of the mobile phase had little effect on the separation factor and resolution.

Enantioselective degradation of Myclobutanil and Famoxadone in grape.

The enantioselective degradation of myclobutanil and famoxadone enantiomers in grape under open field was investigated in this study. The absolute configuration of myclobutanil and famoxadone enantiomers was determined by the combination of experimental electronic circular dichroism (ECD) and calculated ECD spectra. The enantiomers residues of myclobutanil and famoxadone in grape were measured by sensitive high-performance liquid chromatography/tandem mass spectrometry (HPLC-MS/MS). The linearity, precision, accuracy, matrix effect, and stability were assessed. And the limit of quantification (LOQ) for each enantiomer of myclobutanil and famoxadone in grape was evaluated to be 1.5 and 2 µg kg-1. The myclobutanil and famoxadone showed the enantioselective degradation in grape, and the enantioselectivity of degradation for myclobutanil was more pronounced than that for famoxadone. The half-lives were 13.1 days and 25.7 days for S-(+)-myclobutanil and R-(-)-myclobutanil in grape, separately. The half-life of S-(+)-famoxadone was 31.5 days slightly shorter than that of R-(-)-famoxadone with half-life being 38.5 days in grape. The probable reasons for the enantioselective degradation behavior of these two fungicides were also discussed. The results in the article might provide a reference to better assess the risks of myclobutanil and famoxadone enantiomers in grapes to human and environment. Graphical abstract The enantioselective analysis of myclobutanil and famoxadone in grape.

Stereoselective induction of developmental toxicity and immunotoxicity by acetochlor in the early life stage of zebrafish.

Acetochlor (ACT) has been frequently detected in the aquatic environment and implicated in disruption of the immune system in fish, the mechanisms of which, especially at enantiomeric levels, remains unclear. In the present study, embryonic zebrafish were exposed to ACT and its enantiomers at concentrations of 0, 2, 8, 15, 30 and 60 µM from 2 h post-fertilization (hpf) to 72 hpf. We demonstrated that ACT and its enantiomers could cause time- and concentration-dependent mortality (72 h LC50 ranged from 48.4 to 53.1 µM) and developmental malformations (e.g., 48 h EC50 for yolk sac edema ranged from 36.7 to 54.1 µM), as well as increase transcription of the key genes involved in the innate immune system. A consistent enantioselectivity in these endpoints was observed with (-)-R-ACT showed stronger effects than (+)-S-ACT, and the transcription levels of il-1ß exhibited significant enantioselectivity at concentrations as low as 8 µM. Further Western blot analysis revealed that significant elevations of Il-1ß protein expression in all (-)-R-ACT treatment groups. According to the molecular docking and molecular dynamics simulations, the enantioselectivity between ACT enantiomers was attributed to the distinct binding affinity to Il-1ß. Overall, our in vivo and in silico studies uniquely disclosed the enantioselective immunotoxicity of ACT and its underlying mechanisms and highlighted the need to evaluate the environmental risk of chiral chloroacetamide herbicide in aquatic organisms at enantiomeric levels.

In situ Removal of Hydrogen Sulfide During Biogas Fermentation at Microaerobic Condition.

In this paper, rice straw was used as a raw material to produce biogas by anaerobic batch fermentation at 35 °C (mesophilic) or 55 °C (thermophilic). The hydrogen sulfide in biogas can be converted to S0 or sulfate and removed in-situ under micro-oxygen environment. Trace oxygen was conducted to the anaerobic fermentation tank in amount of 0.5, 1.0, 2.0, 3.0, 4.0, 5.0, or 10.0 times stoichiometric equivalence, respectively, and the control experiment without oxygen addition was carried out. The results showed that the initial H2S concentrations of biogas are about 3235 ± 185 mg/m3 (mesophilic) or 3394 ± 126 mg/m3 (thermophilic), respectively. The desulfurization efficiency is 72.3 % (mesophilic) or 65.6 % (thermophilic), respectively, with oxygen addition by stoichiometric relation. When the oxygen feeded in amount of 2∼4 times, theoretical quantity demanded the removal efficiency of hydrogen sulfide could be over 92 %, and the oxygen residue in biogas could be maintained less than 0.5 %, which fit the requirement of biogas used as vehicle fuel or combined to the grid. Though further more oxygen addition could promote the removal efficiency of hydrogen sulfide (about 93.6 %), the oxygen residue in biogas would be higher than the application limit concentration (0.5 %). Whether mesophilic or thermophilic fermentation with the extra addition of oxygen, there were no obvious changes in the gas production and methane concentration. In conclusion, in-situ desulfurization can be achieved in the anaerobic methane fermentation system under micro-oxygen environment. In addition, air could be used as a substitute oxygen resource on the situation without strict demand for the methane content of biogas.

Permethrin is a potential thyroid-disrupting chemical: In vivo and in silico envidence.

Permethrin (PM), one of the most heavily used synthetic pyrethroids, has the potential to interfere with thyroid hormones in mammals, however, the effect is poorly recognized in aquatic organisms. Herein, embryonic zebrafish were exposed to PM (0, 1, 3 and 10µg/L) until 72h post-fertilization. We demonstrated that PM readily accumulated in larvae with a preference for cis-PM, inhibited development and increased thyroxine and 3,5,3'-triiodothyronine levels accompanying increase in the transcription of most target genes, i.e., thyroid-stimulating hormone ß, deiodinases, thyroid receptors, involved in the hypothalamic-pituitary-thyroid axis. Further Western blot analysis indicated that transthyretin (TTR) protein was significantly increased. Molecular docking analysis and molecular dynamics simulations revealed that PM fits into three hydrophobic binding pocket of TTR, one of the molecular targets of thyroid hormone disrupting chemicals (THDCs), and forms strong van der Waals interactions with six resides of TTR, including Leu8, Leu 101, Leu125, Thr214, Leu218 and Val229, thus altering TTR activity. Both in vivo and in silico studies clearly disclosed that PM potentially disrupts the thyroid endocrine system in fish. This study provides a rapid and cost-effective approach for identifying THDCs and the underlying mechanisms.

Enantioselective Metabolism of Flufiprole in Rat and Human Liver Microsomes.

The enantioselective metabolism of flufiprole in rat and human liver microsomes in vitro was investigated in this study. The separation and determination were performed using a liquid chromatography system equipped with a triple-quadrupole mass spectrometer and a Lux Cellulose-2 chiral column. The enantioselective metabolism of rac-flufiprole was dramatically different in rat and human liver microsomes in the presence of the ß-nicotinamide adenine dinucleotide phosphate regenerating system. The half-lives (t1/2) of flufiprole in rat and human liver microsomes were 7.22 and 21.00 min, respectively, for R-(+)-flufiprole, whereas the values were 11.75 and 17.75 min, respectively, for S-(-)-flufiprole. In addition, the Vmax of R-(+)-flufiprole was about 3-fold that of S-(-)-flufiprole in rat liver microsomes, whereas its value in the case of S-(-)-flufiprole was about 2-fold that of R-(+)-flufiprole in human liver microsomes. The CLint of rac-flufiprole also showed opposite enantioselectivy in rat and human liver microsomes. The different compositions and contents of metabolizing enzyme in the two liver microsomes might be the reasons for the difference in the metabolic behavior of the two enantiomers.

Acute exposure to synthetic pyrethroids causes bioconcentration and disruption of the hypothalamus-pituitary-thyroid axis in zebrafish embryos.

Synthetic pyrethroids (SPs) have the potential to disrupt the thyroid endocrine system in mammals; however, little is known of the effects of SPs and underlying mechanisms in fish. In the current study, embryonic zebrafish were exposed to various concentrations (1, 3 and 10 µg/L) of bifenthrin (BF) or λ-cyhalothrin (λ-CH) until 72 h post fertilization, and body condition, bioaccumulation, thyroid hormone levels and transcription of related genes along the hypothalamus-pituitary-thyroid (HPT) axis examined. Body weight was significantly decreased in the λ-CH exposure groups, but not the BF exposure groups. BF and λ-CH markedly accumulated in the larvae, with concentrations ranging from 90.7 to 596.8 ng/g. In both exposure groups, alterations were observed in thyroxine (T4) and triiodothyronine (T3) levels. In addition, the majority of the HPT axis-related genes examined, including CRH, TSHß, TTR, UGT1ab, Pax8, Dio2 and TRα, were significantly upregulated in the presence of BF. Compared to BF, λ-CH induced different transcriptional regulation patterns of the tested genes, in particular, significant stimulation of TTR, Pax8, Dio2 and TRα levels along with concomitant downregulation of Dio1. Molecular docking analyses revealed that at the atomic level, BF binds to thyroid hormone receptor (TRα) protein more potently than λ-CH, consequently affecting HPT axis signal transduction. In vitro and in silico experiments disclosed that during the early stages of zebrafish development, BF and λ-CH have the potential to disrupt thyroid endocrine system.

Dynamics of uptake and elimination of pyrethroid insecticides in zebrafish (Danio rerio) eleutheroembryos.

Synthetic pyrethroids (SPs) are among the most heavily used insecticides for residential and agricultural applications. Their residues have frequently been detected in aquatic ecosystems. Despite their high aquatic toxicity, their toxicokinetics are still unclear. In this study, the kinetics of uptake and depuration of three SPs, permethrin (PM), bifenthrin (BF) and λ-cyhalothrin (λ-CH), were determined for the first time using zebrafish eleutheroembryo assays. The diastereoisomer selectivity of PM in eleutheroembryos was further examined. The results indicated that three SPs were quickly taken up by eleutheroembryos. The bioaccumulation factors of the SPs ranged from 125.4 to 708.4. The depuration of SPs in zebrafish eleutheroembryos followed the first-order process. The elimination rate constants (k2) of SPs in eleutheroembryos ranged from 0.018 h(-1) to 0.0533 h(-1). The half-lives (t1/2) were in the range 13.0-38.5h. The diastereoisomer fraction (DF) values for PM in the eleutheroembryos estimated at different uptake and depuration times were all significantly greater than the original value (DF=0.43), indicating selective enrichment and elimination of cis-PM relative to trans-PM. These results reveal a high capacity for SP bioconcentration by zebrafish eleutheroembryos, suggesting that SPs possess a highly cumulative risk to fish.

Enantioselective interaction of acid α-naphthyl acetate esterase with chiral organophosphorus insecticides.

Many previous works have demonstrated that acetylcholinesterase (AChE) was enantioselectively inhibited by chiral organophosphorus insecticides (OPs) and that a significant difference in reactivation existed for AChE inactivated by (1R)- versus (1S,3S)-stereoisomers of isomalathion. It had been known that α-naphthyl acetate esterase (ANAE), an enzyme which might play an essential role in the growth of plants and the defense of plants against environmental stress by regulating the concentration of hormones in plants, can be inhibited by OPs. However, it was unknown whether interaction of ANAE with chiral OPs was enantioselective. The present work investigated the inhibition kinetics and spontaneous reactivation of ANAE inactivated by enantiomers of malaoxon, isomalathion, and methamidophos. The order of inhibition potency is (R) > (S) for malaoxon, (1R,3R) > (1R,3S) > (1S,3R) > (1S,3S) for isomalathion, and (S) > (R) for methamidophos according to bimolecular rate constants of inhibition (ki), which is consistent with the order observed in the enantioselective inhibition of AChE by malaoxon, isomalathion, and methamidophos. The difference in spontaneous reactivation of AChE inactivated between (1R)- and (1S,3S)-isomers of isomalathion is conserved for ANAE. The observations indicated ANAE and AChE have similar selective inhibition kinetics and postinhibitory reactions in reaction with chiral OPs.

Enantiomeric separations of chiral polychlorinated biphenyls on three polysaccharide-type chiral stationary phases by supercritical fluid chromatography.

Enantiomeric separations of 18 chiral polychlorinated biphenyls (PCBs) were investigated on three polysaccharide-type chiral stationary phases (CSPs; Sino-Chiral OJ, Chiralpak IB, and Chiralcel OD) by supercritical fluid chromatography (SFC). With these commonly used polysaccharide CSPs, 17 PCBs except PCB 135 (R(S) = 0.81) were well resolved (R(S) > 1.5) under appropriate mobile phases and temperatures. Using Sino-Chiral OJ, 14 PCBs could be baseline-separated, while only one and nine PCBs could be completely separated using Chiralpak IB and Chiralcel OD, respectively. The influence of column temperature was studied for the optimization of resolution, as well as for the type and percentage of organic modifier in the mobile phase. The resolution decreased as the temperature increased in the range of 26-40 °C in which the enantiomeric separations were an enthalpy-driven process. The addition of modifiers in the mobile phase decreased the resolution of the PCB enantiomers, but it clearly shortened their retention time. These separation results indicate that SFC is a promising chromatographic technique for chiral separation and enantiopure standard preparation.

Determination of organophosphorus pesticide residues in vegetables by an enzyme inhibition method using α-naphthyl acetate esterase extracted from wheat flour.

The widespread use of organophosphorus pesticides (OPs) poses a great threat to human health and has made the detection of OP residues in food an important task, especially in view of the fact that easy and rapid detection methods are needed. Because OPs have inhibitory effects on the activity of α-naphthyl acetate esterase (ANAE) in plants, in this work we evaluated the possibility of detecting OPs in vegetables with ANAE extracted from commercial flour. The limits of detection (LODs) obtained for methamidophos, dichlorvos, phoxim, dimethoate, and malathion in lettuce samples with crude ANAE were 0.17, 0.11, 0.11, 0.96, and 1.70 mg/kg, respectively. Based on the maximum residue limits (MRLs) for OPs in food stipulated by Chinese laws which are 0.05, 0.20, 0.05, 1.00, and 8.00 mg/kg for methamidophos, dichlorvos, phoxim, dimethoate, and malathion, respectively, the esterase inhibition method with crude ANAE had sufficient sensitivity to detect the residues of dichlorvos, dimethoate, and malathion in lettuce, but it could not be used to guarantee the safety of the same samples if methamidophos or phoxim residue was present. The sensitivity of the method was improved by the use of esterase purified by ammonium sulfate salting-out. The LODs obtained for methamidophos and phoxim with purified esterase were lower than the MRLs for these OPs in food. This is a very promising method for the detection of OP residues in vegetables using crude or purified esterase because of its cheapness, sensitivity, and convenience.

Enantiomeric resolution of five chiral pesticides on a Chiralpak IB-H column by SFC.

The enantiomeric separations of five chiral pesticides, diclofopmethyl, 1; benalaxy, 2; acetofenate, 3; myclobutanil, 4; and difenoconazole, 5, were conducted on a Chiralpak IB-H column by a packed-column supercritical fluid chromatography (p-SFC). All compounds, except difenoconazole and myclobutanil, were well resolved within 10 min. As the mobile phase polarity decreased through changing the percentage and the type of alcohol modifiers in the supercritical carbon dioxide (CO(2)), the retention time, the separation factors, and the resolution increased. However, based on the retention time and the resolution, the optimized separations were obtained with the mobile phase containing 10% 2-propanol for diclofop-methyl 1; benalaxy, 2; myclobutanil, 4; difenoconazole, 5; and containing 3% 2-propanol for acetofenate, 3. The optimized separation temperature was at 35°C under the supercritical fluid condition. The π-π interactions and the hydrogen bonding interactions between Chiralpak IB-H CSP and the analytes might be the main chiral discriminations on enantioseparation of these five pesticides.