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Cinnamomum camphora seed kernels (CCSKs) are rich in phytochemicals, especially plant extracts. Phytochemicals play a vital role in therapy due to their strong antioxidant and anti-inflammatory activities. Extracts from CCSK can be obtained through multiple steps, including pretreatment, extraction and purification, and the purpose of pretreatment is to separate the oil from other substances in CCSKs. However, C. camphora seed kernel extracts (CKEs) were usually considered as by-products and discarded, and their potential bioactive values were underestimated. Additionally, little has been known about the effect of pretreatment on CKE. This study aimed to investigate the effects of pretreatment methods (including the solvent extraction method, cold pressing method, aqueous extraction method and sub-critical fluid extraction method) on the extraction yields, phytochemical profiles, volatile compounds and antioxidant capacities of different CKE samples. The results showed that the CKE samples were rich in phenolic compounds (15.28–20.29%) and alkaloids (24.44–27.41%). The extraction yield, bioactive substances content and in vitro antioxidant capacity of CKE pretreated by the sub-critical fluid extraction method (CKE-SCFE) were better than CKEs obtained by other methods. CKE pretreated by the solvent extraction method (CKE-SE) showed the best lipid emulsion protective capacity. Moreover, the volatile substances composition of the CKE samples was greatly influenced by the pretreatment method. The results provided a fundamental basis for evaluating the quality and nutritional value of CKE and increasing the economic value of by-products derived from CCSK. [ABSTRACT FROM AUTHOR]

[Objective] It is of great significance for clarifying the influence of different pretreatment methods on the measurement of soil particle composition(PSD), which is the basis of studies on water transport, nutrient transport, soil erosion and sediment transport processes. Soil particle composition(PSD) is the basis of soil physical properties and has important implications for [Methods] Typical purple soil natural woodland profile soil(0-110 cm) was selected, and 9 pretreatment methods were adopted, including physical methods of soaking and shaking, and chemical methods of H2O2 and HCl treatment, and then particle analysis was carried out with a Mastersizer 2000 laser particle size analyzer. [Results](1) The median particle size of each physical pretreatment decreased by 33.79 μm on average compared with the direct measurement without any pretreatment(control). The median particle size under pretreatments of soaking, shaking for 2 h, and shaking for 10 h decreased sequentially, but their release effects on clay were weak. There was no significant difference in clay content between different shaking times(p＞0.05). The median particle size of each chemical treatment could be reduced by 32.72 μm on average compared with control. Among them, the H2O2 treatments had a stronger dispersing effect than the HCl treatments, and the clay contents of H2O2 treatments were the highest among all treatments, which were greater than 4%.(2) Each physical pretreatment method had a uniform dispersion effect among soil layers. Sensitivity to different H2O2 dosage of different layer of soil was middle(30-70 cm)＞lower(70-110 cm)＞upper(0-30 cm). Specifically, sand content in the 20-90 cm soil layer under sufficient H2O2 pretreatment increased by 9.5% and silt content decreased by 9.7% compared with 10 ml H2O2 pretreatment. Sensitivity to different HCl pretreatments of different layer of soil was upper and middle＞lower, specifically the sand content of the upper and middle soil(0-90 cm) increased by 6.2% on average under the treatment of 10 ml HCl plus acid washing compared with the treatment without acid washing. The silt content reduced by an average of 5.4%. There was no significant difference in clay content among soil layers under these treatments.(3) There was a significant linear correlation(r＞0.8) between the content of sand and silt and the content of organic matter in the profile under the treatment of sufficient H2O2, but there was no significant correlation between the content of calcium carbonate and any particles under the treatment of HCl. [Conclusion] There are significant differences in PSD between different pretreatment methods, and the amount of reagent in chemical pretreatments affects the PSD obviously, too. This study can provide a reference for the analysis of purple soil particle composition under different research purposes. [ABSTRACT FROM AUTHOR]

旨在研究原料压榨制油的预处理方式对核桃多肽性质的影响。对核桃仁分别进行未预处理、去衣、焙烤预处理后，进行压榨提油，以提油后的饼为原料，经正己烷脱脂，碱性蛋白酶酶解制备核桃多肽，测定核桃多肽的功能特性和ACE抑制活性。结果表明：与未预处理、焙烤预处理比较，去衣预处理的核桃多肽的持水性(50 ℃，5.11 g/g)、吸油性(50 ℃，3.25 g/g)、乳化性(pH 9.0,6257%)、乳化稳定性(pH 9.0,84.51%)、起泡性(pH 9.0,117.49%)及ACE抑制率（63.04%）最高。综上，以去衣预处理压榨制油后的核桃饼为原料制备的核桃多肽具有良好的功能特性和ACE抑制活性。The aim was to study the effect of pretreatment methods of raw material pressing for oil on the properties of walnut polypeptide. The walnut kernels were untreated, peeled and roasted respectively,then pressed to extract oil.The cake after oil extraction was defatted by n-hexane and hydrolyzed by alkaline protease to produce walnut polypeptide, and the functional properties and ACE inhibitory activity of walnut polypeptide were determined. The results showed that compared with no treatment and roasting pretreatment, walnut polypeptide obtained by peeling of raw material had the highest water holding capacity (50 ℃, 5.11 g/g), oil absorption (50 ℃,3.25 g/g), emulsifying ability (pH 9.0, 62.57%), emulsifying stability (pH 9.0, 84.51%), foaming ability (pH 9.0, 117.49%) and ACE inhibitory rate( 63.04%). In conclusion, the walnut polypeptide prepared from walnut cake after peeling and pressing for oil production had good functional properties and ACE inhibitory activity.

The demand for hygiene products has increased worldwide since the outbreak of global COVID-19. As the hygiene products market is expanding, it is necessary to manage microbial contamination in wet towels and wet wipes. This study evaluated pretreatment methods for microbial recovery from wet towels and wipes and microbial contamination levels in wet towels and wipes with the pretreatment method. Escherichia coli (NCCP14038 and NCCP14039), Staphylococcus aureus (ATCC25923 and ATCC29213), and Pseudomonas aeruginosa (NCCP10250 and NCCP11229) were inoculated on five fabric materials of wet towels and wet wipes. The recovery rates of the bacteria from wet towels and wet wipes using three pretreatment methods (pummeling, hand shaking, and portion cutting method) were investigated. Using the selected pretreatment method, the contamination levels of E. coli, S. aureus, and P. aeruginosa were evaluated for 238 wet towels and 244 wet wipes, which were collected in April to August, 2019. The presence of toxA and antibiotic resistance of P. aeruginosa isolated from wet towels were evaluated. The overall recovery rates of the pummeling method and hand shaking method were higher than the portion cutting method. Considering the convenience, the pummeling method was used to investigate the microbial contamination in the wet towels and wet wipes. P. aeruginosa was detected in two wet towels at an average of 9.9×102 CFU/towel. E. coli and S. aureus were not detected in both wet towels and wipes. P. aeruginosa isolates showed no resistances to piperacillin, piperacillin-tazobactam, aztreonam, and gentamicin, but had toxA. The results indicate that the pummeling method is the most appropriate pretreatment method for the recovery of microorganisms, and microbial analysis showed that this method could be useful in monitoring microbial contamination in wet towels and wet wipes.

Three pretreatment methods, including direct extraction method, neutral alumina column method and molecular imprinted column method, were established for the determination of benzo (a) pyrene in vegetable oil by high performance liquid chromatography-fluorescence detector. The results showed that the linear relationship between the concentration of benzo (a) pyrene standard curve and the corresponding hromatographic peak area was good, and the correlation coefficient was 0.9993, when the concentration was in the range of 0.5~50 ng/mL. The blank vegetable oil was used as the matrix to carry out the spike recovery experiment. When the addition levels of benzo (a) pyrene were 2, 15 and 25 μg/kg, the average recoveries of direct extraction method, molecular imprinted column method and neutral alumina column method were 98.8%~102.8% and 91.1%~101.0% and 91.8%~113.7%, respectively, and the relative standard deviations (RSD) were 0.8%~2.0%, 2.3%~7.3% and 1.9%~8.8%, respectively. The direct extraction method has the advantages of simple pretreatment, good precision, high accuracy and sensitivity, and low cost, and is suitable for the detection of benzo (a) pyrene in vegetable oil.

Cinnamomum camphora seed kernels (CCSKs) are rich in phytochemicals, especially plant extracts. Phytochemicals play a vital role in therapy due to their strong antioxidant and anti-inflammatory activities. Extracts from CCSK can be obtained through multiple steps, including pretreatment, extraction and purification, and the purpose of pretreatment is to separate the oil from other substances in CCSKs. However, C. camphora seed kernel extracts (CKEs) were usually considered as by-products and discarded, and their potential bioactive values were underestimated. Additionally, little has been known about the effect of pretreatment on CKE. This study aimed to investigate the effects of pretreatment methods (including the solvent extraction method, cold pressing method, aqueous extraction method and sub-critical fluid extraction method) on the extraction yields, phytochemical profiles, volatile compounds and antioxidant capacities of different CKE samples. The results showed that the CKE samples were rich in phenolic compounds (15.28–20.29%) and alkaloids (24.44–27.41%). The extraction yield, bioactive substances content and in vitro antioxidant capacity of CKE pretreated by the sub-critical fluid extraction method (CKE-SCFE) were better than CKEs obtained by other methods. CKE pretreated by the solvent extraction method (CKE-SE) showed the best lipid emulsion protective capacity. Moreover, the volatile substances composition of the CKE samples was greatly influenced by the pretreatment method. The results provided a fundamental basis for evaluating the quality and nutritional value of CKE and increasing the economic value of by-products derived from CCSK.

Phosphate oxygen isotope (δ18OP) technique is an effective tool to identify the source and transformation process of phosphorus. The poor applicability of existing δ18OP pretreatment methods for sediments hindered the large-scale application of δ18OP technology. This paper presents an optimization framework for the pretreatment of sediment δ18OP samples based on large-scale applications, using the Fuyang River Basin as a case study. The typical channel landscape outflow lake, South Lake, was selected as the most favorable point for assessing the applicability and optimizing the mainstream δ18OP pretreatment method, which was achieved by clarifying the sediment environmental characteristics of South Lake. To evaluate the suitability of the Blake and McLaughlin methods in South Lake, a comparative study was carried out based on five dimensions: phosphorus recovery rate, removal efficiency of organic matter, removal efficiency of extraction liquid impurity ion, experimental time, and reagent consumption cost. The findings demonstrated that the Blake method outperformed the McLaughlin method across all five dimensions. Based on the environmental characteristics of the sediments of South Lake, the Blake method was optimized from two perspectives, namely the substitution of reagents and adjustment and optimization of experimental procedures. This resulted in an enhancement of phosphorus recovery and organic matter removal efficiency, while also reducing the experimental time required. The optimized method also yielded satisfactory results when applied to the entire watershed. This research paper can thus offer valuable technical support for the widespread application of sediment δ18OP technology.

BACKGROUND: Shale, as an important component of sedimentary rocks, is also a valuable source rock and “reservoir” of shale gas. The study of nitrogen isotope distribution characteristics can provide geochemical indexes for judging the sedimentary environment and oil-source correlation of crude oil. It is helpful to understand the organic matter enrichment mechanism of black shale, shale oil, and gas exploration[14-17] . Nitrogen isotope ratio analysis in sedimentary rocks is faced with problems such as low content, and the influence of pretreatment on analysis and the reference materials, which affect the accurate analysis of nitrogen isotope ratio in shale and restrict the development of this technology in related studies. First, the low content in rocks will affect the analysis results by elemental analyzer-isotope ratio mass spectrometry (EA-IRMS)[16,18,20] . Second, the method of direct sample analysis is often used to analyze nitrogen isotope ratio of whole rock, to improve the relative content of nitrogen and remove carbonate to meet the requirement of organic carbon isotope analysis; samples treated with acid can also be used for analysis. There are differences in treatment methods in different laboratories, which can also increase the variation in content and isotope ratios, as well as the difficulty of data comparison[9-13,21,25] . Finally, there are relatively few international standard materials based on rocks and minerals for nitrogen isotope and there are still some problems and limitations in these standards[7,21,24,30] . Therefore, the accurate analysis of nitrogen isotope ratio in shale is affected, thus restricting the development of this technology in related studies. OBJECTIVES: To improve the precision and accuracy of nitrogen isotope analysis in shales. METHODS: (1) The analysis was carried out by EA-IRMS, with the use of MAT253 Plus gas stable isotope mass spectrometer, Flash 2000 HT element analyzer and ConFlo Ⅳ interface. The furnace tube was filled with the recommended scheme of the instrument, and the water removal trap was adjusted according to the measured object, that is, only magnesium perchlorate was used or carbon adsorbent was added on this basis (the main component was sodium hydroxide), which accounted for 50% each. Carbon and nitrogen isotope ratios were measured separately. (2) Carbon and nitrogen isotope standard materials included: USGS40, USGS41a, IAEA-600, Urea, GBW04701, GBW04702, GBW04703, GBW07424 and GBW07107 as calibration, monitoring and experimental study (Table 1). Typical shale samples of the upper Yangtze Longmaxi Formation were selected as the research object. Both samples are rich in organic carbon. Combined with hand samples and XRD analysis, their mineral composition is mainly as follows: Quartz, potassium feldspar, illite and pyrite in SAMPLE-1, SAMPLE-2 are similar in mineral composition in general, but there is obvious dolomite in SAMPLE-2. (3) The experiment consisted of three parts. First, the impact of increasing oxygen injection time and using double tin cup encapsulation on nitrogen isotope ratio analysis was studied. Urea was applied to determine δ15N under the same conditions but with different oxygen injection time (3s or 5s) and the differences were compared. Urea and GBW07424 were used to encapsulate the sample with double tin cup (two layers of tin cup for the same sample) and conventional single tin cup for comparison under the same conditions. The composition of total nitrogen and total carbon isotope ratios in GBW04701, GBW04702 and GBW04703 was determined by single-tin cup encapsulation. Second, the influence of acid rinse method on the analysis was conducted. Standards were weighed and gradually added with an excess of 6mol/L HCl to remove carbonate minerals. During the reaction, the centrifuge tube was placed in an ultrasonic cleaner for ultrasonic treatment for 3 to 5 times, 10min each time. Centrifuge was used, acid was discarded and deionized water was added. After ultrasonic treatment in ultrasonic cleaner, centrifuge treatment was continued. This process was repeated until it reached neutral. The samples were then compared and analyzed with unprocessed samples and recommended values. Finally, the shale samples SAMPLE-1 and SAMPLE-2 from Longmaxi Formation were analyzed. The isotopic ratios of total nitrogen and DISCUSSION: (1) The optimized measurement conditions of EA-IRMS. Attempts were made to improve combustion efficiency by using double tin cup wrapping and increasing oxygen injection time. The relative deviation of double tin cup method was greater than 0.2‰ and obviously higher than that of single tin cup method, indicating that this method is not suitable. The reason may be related to the difference in combustion efficiency caused by the gap between double tin cups and the introduction of air when the sample is wrapped[19] . Appropriate increase of oxygen injection time in the analysis of GBW04701, GBW04702 and GBW04703 obtained satisfactory results, indicating that this method can effectively improve the accuracy of the technique, while this method did not significantly improve the standard deviation of δ15N value of Urea, which may be related to the matrix of the sample[20] . It may be the abundant carbon in shale. Therefore, it is necessary for nitrogen isotope ratio analysis in shale to be determined by carbon and nitrogen separately and adding carbon adsorbent. (2) The acid rinse method. The acid rinse method adopted has no significant effect on GBW04701 and GBW04702 on δ15N analysis and can effectively remove carbonate components. Ultrasonic was used to promote the reaction between acid/water and sample in the process of acid reaction and acid washing in the experiment, and the centrifugation time was appropriately increased in the centrifugation stage, which was conducive to the preservation of fine particle components. Compared with static reaction, the addition of ultrasonic reaction could improve the washing effect. The less washing times were thus contributing to the accuracy of δ15N analysis[47] . (3) The shale sample analysis. Although the acid treatment method adopted in the experiment has no obvious effect on the δ15N analysis of standards, significant composition loss and δ15N change were still observed in the analysis of shale samples. Moreover, the nitrogen content of shale samples of Longmaxi Formation was relatively high. Therefore, in order to accurately analyze the nitrogen content and δ15N analysis, direct analysis of samples is recommended for the whole-rock nitrogen isotope analysis of such samples. (4) The standard and reference materials. Carbon and nitrogen isotope reference materials with different characters and compositions were selected as calibration, monitoring and experimental study. USGS40, USGS41a and IAEA-600 standard samples were used for calibration and quality monitoring, and no obvious influence of matrix difference was found. Although they are Marine sediments, GBW04701, GBW04702, GBW04703 provide isotopic compositions of total carbon, organic carbon, total nitrogen and organic nitrogen. They are suitable for the analysis of carbon and nitrogen isotope ratios and the monitoring of acid treatment processes, especially the analysis of EA-IRMS technology[50] . In shale analysis, GBW04701, GBW04702 and GBW04703 were selected as monitoring to meet the requirements of nitrogen and total carbon and organic carbon isotope ratio analysis. [ABSTRACT FROM AUTHOR]

The utilization of recycled aggregate can avert the squandering of resources and the destruction of the environment. Nevertheless, there exists a slew of old cement mortar and microcracks on the surface of recycled aggregate, which give rise to the poor performance of aggregates in concrete. In this study, for the sake of ameliorating this property of recycled aggregates, the surface of the recycled aggregates is covered with a layer of cement mortar to compensate for the microcracks on the surface and reinforce the bond between old cement mortar and aggregates. In order to demonstrate the influence of recycled aggregate by different cement mortar pretreatment methods, this study prepared natural aggregate concrete (NAC) and concretes with recycled aggregate after the wetting pretreatment (RAC-W) and cement mortar pretreatment (RAC-C), and conducted uniaxial compressive strength tests on different types of concrete at different curing ages. The test results indicated that the compressive strength of RAC-C at a 7 d curing age was higher than that of RAC-W and NAC, and the compressive strength of RAC-C at a 28 d curing age was higher than RAC-W but lower than NAC. The compressive strength of NAC and RAC-W at a 7 d curing age was about 70% of that at a 28 d curing age, and the compressive strength of RAC-C at a 7 d curing age was about 85–90% of that at a 28 d curing age. The compressive strength of RAC-C increased dramatically at the early stage, while the post-strength of the NAC and RAC-W groups increased rapidly. The fracture surface of RAC-W mainly occurred in the transition zone between the recycled aggregates and old cement mortar under the pressure of the uniaxial compressive load. However, the main failure of RAC-C was the crushing destruction of cement mortar. With changes in the amount of cement added beforehand, the proportion of aggregate damage and A-P interface damage of RAC-C also changed accordingly. Therefore, the recycled aggregate pretreated with cement mortar can significantly improve the compressive strength of recycled aggregate concrete. The optimal amount of pre-added cement was 25%, which is recommended for practical engineering. [ABSTRACT FROM AUTHOR]

The "Dangshan" pear woolliness response is a physiological disease that mostly occurs in the pear growth process. The appearance of the disease is not obvious, and it is difficult to detect with the naked eye. Therefore, finding a way to quickly and nondestructively identify "Dangshan" pear woolliness disease is of great significance. In this paper, the near-infrared spectral (NIR) data of "Dangshan" pear samples were collected at 900–1700 nm reflectance spectra using a handheld miniature NIR spectrometer, and the data were modelled and analysed using random forest (RF), support vector machine (SVM) and boosting algorithms under the processing of 24 pretreatment methods. Considering the variations between different pretreatment methods, this work determined the relative optimality index of different pretreatment methods by evaluating their effects on model accuracy and Kappa and selected the best-performing first derivative with standard normal variate and Savitzky–Golay and first derivative with multiplicative scatter correction and Savitzky–Golay as the best pretreatment methods. With the best pretreatment method, all five models in the three categories showed good accuracy and stability after parameter debugging, with accuracy and F1 greater than 0.8 and Kappa floating at approximately 0.7, reflecting the good classification ability of the models and proving that near-infrared spectroscopy (NIRS) in the rapid identification of "Dangshan" pear woolliness response disease was feasible. By comparing the performance differences of the models before and after the pretreatment methods, it was found that the ensemble-learning models such as RF and boosting were more stringent on pretreatment methods in identifying "Dangshan" pear woolliness response disease than support vector machines, and the performance of the ensemble learning models was significantly improved under appropriate pretreatment methods. This experiment provided a relatively stable detection method for "Dangshan" pear woolliness response disease under nonideal detection conditions by analysing the impact of pretreatment methods and models on the prediction result. [ABSTRACT FROM AUTHOR]

Lignocellulosic biomass is a source of carbohydrates that can be used in the production of biogas. The aim of this study was to obtain biogas from biomass waste (leaves, stems and seed bagasse) of Ricinus communis, applying pretreatments such as temperature and humidity. We examined the effect of these pretreatments on the biomass, two enzymatic pretreatments (cellulase and cellobiohydrolase), two chemicals (NaOH and HCl) and two controls (dried castor straw and seed bagasse) on the methane content. The experiment was performed in two anaerobic digestion (AD) assays at a controlled temperature (37 °C) and at room temperature, with a hydraulic retention time (HRT) of 55 days. The results showed that the residues of the seed bagasse produced the highest biogas yields both at room temperature and at the controlled temperature since this material at 37 °C produced 460.63 mL gVS−1 under cellulase pretreatment; at room temperature, the highest level of production was found for the control (263.41 mL gVS−1). The lowest yields at the controlled temperature and room temperature were obtained from residues of Ricinus communis treated with cellobiohydrolase and the seed bagasse treated with alkaline (15.15 mL gVS−1 and 78.51 mL gVS−1, respectively). Meanwhile, the greatest amount of methane was produced by seed bagasse treated with cellobiohydrolase at a controlled temperature (92.2% CH4) and the lowest content of CH4 (15.5%) was obtained at a controlled temperature from castor straw under the control treatment. [ABSTRACT FROM AUTHOR]

Blending biodegradable polymers with plant materials is an effective method to improve the biodegradability of solid carbon sources and save denitrification costs, but the recalcitrant lignin in plant materials hinders the microbial decomposition of available carbon sources. In the present study, corncob pretreated by different methods was used to prepare polybutylene succinate/corncob (PBS/corncob) composites for biological denitrification. The PBS/corncob composite with alkaline pretreatment achieved the optimal NO3−-N removal rate (0.13 kg NO3−-N m−3 day−1) with less adverse effects. The pretreatment degree, temperature, and their interaction distinctly impacted the nitrogen removal performance and dissolved organic carbon (DOC) release, while the N2O emission was mainly affected by the temperature and the interaction of temperature and pretreatment degree. Microbial community analysis showed that the bacterial community was responsible for both denitrification and lignocellulose degradation, while the fungal community was primarily in charge of lignocellulose degradation. The outcomes of this study provide an effective strategy for improving the denitrification performance of composite carbon sources. [ABSTRACT FROM AUTHOR]

A simple, rapid, sensitive, accurate, and automatic graphite furnace atomic absorption spectrometry (GFAAS) method for detecting Cd and Pb in cereals is presented. This method enables the simultaneous determination of Cd and Pb in cereals with a pre-treatment method of diluted acid extraction and a high-performance lead–cadmium composite hollow-cathode lamp (LCC-HCL), and it realizes automatic determination from sample weighing to result output through an automatic diluted acid extraction system. Under the optimization, Pb and Cd in cereals were simultaneously and automatically detected in up to 240 measurements in 8 h. The LOD and LOQ of this method were 0.012 and 0.040 mg·kg−1 for Pb, and 0.0014 and 0.0047 mg·kg−1 for Cd, respectively. The results of the four certified reference materials were satisfied; there was no significant difference compared with the ICP-MS method according to a t-test, and the RSDs were less than 5% for Cd and Pb. The recoveries of naturally contaminated samples compared with the ICP-MS method were favorable, with 80–110% in eight laboratories. The developed method is rapid, low-cost, and highly automated and may be a good choice for grain quality discrimination and rapid analysis of Cd and Pb in different institutions. [ABSTRACT FROM AUTHOR]

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The “Dangshan” pear woolliness response is a physiological disease that mostly occurs in the pear growth process. The appearance of the disease is not obvious, and it is difficult to detect with the naked eye. Therefore, finding a way to quickly and nondestructively identify “Dangshan” pear woolliness disease is of great significance. In this paper, the near-infrared spectral (NIR) data of “Dangshan” pear samples were collected at 900–1700 nm reflectance spectra using a handheld miniature NIR spectrometer, and the data were modelled and analysed using random forest (RF), support vector machine (SVM) and boosting algorithms under the processing of 24 pretreatment methods. Considering the variations between different pretreatment methods, this work determined the relative optimality index of different pretreatment methods by evaluating their effects on model accuracy and Kappa and selected the best-performing first derivative with standard normal variate and Savitzky–Golay and first derivative with multiplicative scatter correction and Savitzky–Golay as the best pretreatment methods. With the best pretreatment method, all five models in the three categories showed good accuracy and stability after parameter debugging, with accuracy and F1 greater than 0.8 and Kappa floating at approximately 0.7, reflecting the good classification ability of the models and proving that near-infrared spectroscopy (NIRS) in the rapid identification of “Dangshan” pear woolliness response disease was feasible. By comparing the performance differences of the models before and after the pretreatment methods, it was found that the ensemble-learning models such as RF and boosting were more stringent on pretreatment methods in identifying “Dangshan” pear woolliness response disease than support vector machines, and the performance of the ensemble learning models was significantly improved under appropriate pretreatment methods. This experiment provided a relatively stable detection method for “Dangshan” pear woolliness response disease under nonideal detection conditions by analysing the impact of pretreatment methods and models on the prediction result.

[Display omitted] • Freshwater sediment microplastics (MPs) sample pretreatment method was established. • The established pretreatment method achieved MPs recovery of 88.9%. • A modular device is built based on the established protocol. • The device is highly reproducible with recovery of 80% and has a great potential. Microplastics (MPs) have been detected in various environmental matrices, drinking water, and food, and their presence is an ecological and human health concern. Most research on MPs has focused solely on their detection and analysis. However, sample pretreatment methods are critical for accurate MP analysis and must be properly established. In particular, freshwater sediment contains more impurities than other environment samples, thus requiring more elaborate sample pretreatment. Therefore, research on this media and corresponding pretreatment needs to be performed. Herein, we present a sample pretreatment method for analyzing MPs in freshwater sediments. Detailed factors in arriving at this pretreatment process were evaluated and discussed. Using this established pretreatment method, a total average recovery of six types of standard MPs (HDPE, LDPE, PS, PP, PET, and PVC) for sizes of ≥ 100 µm, 20–100 µm, and 1–20 µm was 94.0%, 90.2%, and 82.5%, respectively. After recovery validation, a modular pretreatment device was developed and combined with the established pretreatment method. The developed device performs density separation and organic matter removal, resulting in about 80% recovery of standard MPs. In addition, natural freshwater sediment samples were prepared using an established pretreatment method, and MPs in streams were analyzed using FTIR, TED-GC–MS, and Pyr-GC–MS. The device affords a low-cost, simple, efficient tool for sample pretreatment steps and easy MP recovery. Thus, it has great potential to simplify sample pretreatment steps for easy MP monitoring, especially for freshwater sediment samples. [ABSTRACT FROM AUTHOR]

Lignocellulosic biomass is a source of carbohydrates that can be used in the production of biogas. The aim of this study was to obtain biogas from biomass waste (leaves, stems and seed bagasse) of Ricinus communis, applying pretreatments such as temperature and humidity. We examined the effect of these pretreatments on the biomass, two enzymatic pretreatments (cellulase and cellobiohydrolase), two chemicals (NaOH and HCl) and two controls (dried castor straw and seed bagasse) on the methane content. The experiment was performed in two anaerobic digestion (AD) assays at a controlled temperature (37 °C) and at room temperature, with a hydraulic retention time (HRT) of 55 days. The results showed that the residues of the seed bagasse produced the highest biogas yields both at room temperature and at the controlled temperature since this material at 37 °C produced 460.63 mL gVS−1 under cellulase pretreatment; at room temperature, the highest level of production was found for the control (263.41 mL gVS−1). The lowest yields at the controlled temperature and room temperature were obtained from residues of Ricinus communis treated with cellobiohydrolase and the seed bagasse treated with alkaline (15.15 mL gVS−1 and 78.51 mL gVS−1, respectively). Meanwhile, the greatest amount of methane was produced by seed bagasse treated with cellobiohydrolase at a controlled temperature (92.2% CH4) and the lowest content of CH4 (15.5%) was obtained at a controlled temperature from castor straw under the control treatment.

A simple, rapid, sensitive, accurate, and automatic graphite furnace atomic absorption spectrometry (GFAAS) method for detecting Cd and Pb in cereals is presented. This method enables the simultaneous determination of Cd and Pb in cereals with a pre-treatment method of diluted acid extraction and a high-performance lead–cadmium composite hollow-cathode lamp (LCC-HCL), and it realizes automatic determination from sample weighing to result output through an automatic diluted acid extraction system. Under the optimization, Pb and Cd in cereals were simultaneously and automatically detected in up to 240 measurements in 8 h. The LOD and LOQ of this method were 0.012 and 0.040 mg·kg−1 for Pb, and 0.0014 and 0.0047 mg·kg−1 for Cd, respectively. The results of the four certified reference materials were satisfied; there was no significant difference compared with the ICP-MS method according to a t-test, and the RSDs were less than 5% for Cd and Pb. The recoveries of naturally contaminated samples compared with the ICP-MS method were favorable, with 80–110% in eight laboratories. The developed method is rapid, low-cost, and highly automated and may be a good choice for grain quality discrimination and rapid analysis of Cd and Pb in different institutions.

The prevalent pretreatment method for sulfur isotope determination in water samples is to convert dissolved SO2-4 into solid BaSO4. However, when this method is applied to sulfate samples with small volume and low-concentration (0～20 mg·L-1), there are some problems such as time-consuming and low recovery rate, which would cause uncertain effects on the results of sulfur isotope determination. In this paper, considering the effects of different conditions(Ba2+ addition, reaction temperature, pH, settling time) on recovery rate and determination of δ34S BaSO4, the method of converting dissolved SO2-4 into solid BaSO4 was optimized. In addition, the optimized method has been tested in four different types of water samples(rain water, lake water, sewage and seawater) . The results show: 1) The recovery rate of SO2-4 was controlled by the precipitation generating rate and reaction time. Under the condition of the the same reaction time, the precipitation generating rate was positively correlated with the super-saturation ratio and temperature, while negatively with the concentration of H+, and stirring can accelerate the formation of BaSO4 crystals. 2) The optimized pretreatment process is as follows: add appropriate amount of hydrochloric acid and barium chloride to the water sample（pH=2.6, super-saturation ratio≥55）, and stir with a glass rod at a constant speed for 1 minute, heat in a water bath at 90 ℃ for 1 hour, then cool to normal temperature and use filter membrane to collect solid BaSO4. 3) The optimized pretreatment method has been tested in natural samples, the test result shows that dissolved SO2-4can be completely converted into solid BaSO4 within 1 hour without any sulfur isotope fractionization. In rainwater samples with low SO2-4 concentration (3.24 mg·L-1), the conversion rate increased from 0 to 98.7%, and the δ34S value was determined to be about 15.7‰±0.1‰; in lake water samples with medium SO2-4 concentration (30.34 mg·L-1) , the conversion rate increased from 26% to 100%, and the δ34S value was determined to be 5.8‰±0.2‰. While, the recovery rate or δ34S value in sewage and seawater samples with high SO2-4 concentration (140.4～2 516.4 mg·L-1) are close to that got by prevalent method. In conclusion, the optimized pretreatment method effectively increases the recovery rate of low-concentration water-soluble sulfate samples and avoids sulfur isotope fractionization during the conversion process. Evidently, this optimized method is also applicable to samples with medium and high SO2-4concentrations.

With the increase in demand, artificially planting Chinese medicinal materials (CHMs) has also increased, and the ensuing pesticide residue problems have attracted more and more attention. An optimized quick, easy, cheap, effective, rugged and safe (QuEChERS) method with multi-walled carbon nanotubes as dispersive solid-phase extraction sorbents coupled with surface-enhanced Raman spectroscopy (SERS) was first proposed for the detection of deltamethrin in complex matrix Corydalis yanhusuo. Our results demonstrate that using the optimized QuEChERS method could effectively extract the analyte and reduce background interference from Corydalis. Facile synthesized gold nanoparticles with a large diameter of 75 nm had a strong SERS enhancement for deltamethrin determination. The best prediction model was established with partial least squares regression of the SERS spectra ranges of 545~573 cm−1 and 987~1011 cm−1 with a coefficient of determination (R2) of 0.9306, a detection limit of 0.484 mg/L and a residual predictive deviation of 3.046. In summary, this article provides a new rapid and effective method for the detection of pesticide residues in CHMs.

Phosphate oxygen isotope (δ 18 O P ) technique is an effective tool to identify the source and transformation process of phosphorus. The poor applicability of existing δ 18 O P pretreatment methods for sediments hindered the large-scale application of δ 18 O P technology. This paper presents an optimization framework for the pretreatment of sediment δ 18 O P samples based on large-scale applications, using the Fuyang River Basin as a case study. The typical channel landscape outflow lake, South Lake, was selected as the most favorable point for assessing the applicability and optimizing the mainstream δ 18 O P pretreatment method, which was achieved by clarifying the sediment environmental characteristics of South Lake. To evaluate the suitability of the Blake and McLaughlin methods in South Lake, a comparative study was carried out based on five dimensions: phosphorus recovery rate, removal efficiency of organic matter, removal efficiency of extraction liquid impurity ion, experimental time, and reagent consumption cost. The findings demonstrated that the Blake method outperformed the McLaughlin method across all five dimensions. Based on the environmental characteristics of the sediments of South Lake, the Blake method was optimized from two perspectives, namely the substitution of reagents and adjustment and optimization of experimental procedures. This resulted in an enhancement of phosphorus recovery and organic matter removal efficiency, while also reducing the experimental time required. The optimized method also yielded satisfactory results when applied to the entire watershed. This research paper can thus offer valuable technical support for the widespread application of sediment δ 18 O P technology., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2023 The Authors.)

31P Nuclear Magnetic Resonance (31P NMR) is an important analytical tool for identifying and quantifying phosphorus-based compounds in aquatic environments. However, the precipitation method typically used for analyzing phosphorus species via 31P NMR has limited application. To expand the scope of the method and apply it to highly mineralized rivers and lakes worldwide, we present an optimization technique that employs H resin to assist phosphorus (P) enrichment in highly mineralized lake water. To explore how to reduce analysis interference from salt in highly mineralized water and improve the accuracy of P analysis using 31P NMR, we conducted case studies on Lake Hulun and Qing River. This study aimed to increase the efficiency of phosphorus extraction in highly mineralized water samples by using H resin and optimizing key parameters. The optimization procedure included determining the enriched water volume, H resin treatment time, AlCl 3 addition amount, and precipitation time. The final recommended optimization enrichment procedure involves treating 10 L of filtered water sample with 150 g of Milli-Q water-washed H resin for 30 s, adjusting the pH of the treated sample to 6–7, adding 1.6 g of AlCl 3 , stirring the mixture, and allowing the solution to settle for 9 h to collect the flocculated precipitate. The precipitate was then extracted with 30 mL of 1 M NaOH +0.05 M DETA extraction solution at 25 °C for 16 h, and the supernatant was separated and lyophilized. The lyophilized sample was redissolved in 1 mL of 1 M NaOH +0.05 M EDTA. This optimized analytical method using 31P NMR effectively identified phosphorus species in highly mineralized natural waters and can be applied to other highly mineralized lake waters globally. [Display omitted] • H-resin techniques increase phosphorus enrichment in highly mineralized water. • Orthophosphate diesters made the most significant part of dissolved organic phosphorus in Lake Hulun water. • The abundance of Mg2+ in highly mineralized water hindered the enrichment of phosphorus. [ABSTRACT FROM AUTHOR]

The determination of inorganic elements in plant samples is very important for the research of environmental geochemistry and biogeochemistry. The content of elements in plant samples is characteristically low, deeming it necessary for the determination technique to be highly sensitive, with excellent precision and an as-low-as-possible detection limit. A comparison of the current pretreatment methods for plant samples is described in this paper, namely, dry ashing, wet digestion, and microwave digestion. Pretreatment method is selected based on the characteristics of samples and target elements. The advantage of dry ashing is less consumption of reagent and low level blank, but is unsuitable for compact-tissue samples and some volatile elements. Wet digestion is a complete digestion method for most samples, but its disadvantages of high consumption of reagent, high level blank and complex procedure. Microwave digestion can avoid loss of some volatile elements with less reagent and rapid digestion, but it is unsuitable for large weighing samples. At present, most instrument techniques are suitable for plant sample analysis, based on the target element, interference correction method and matrix modification method. More than 40 elements can be determined by Inductively Coupled Plasma-Mass Spectrometry (ICP-MS), and the detection limit of high resolution ICP-MS is fg/mL level. Inductively Coupled Plasma-Atomic Emission Spectrometry is suitable for determination of high content elements such as P, K and Na in plant samples. Atomic Absorption Spectrometry can determine more than 70 elements, and is one of the most popular techniques. The hydride generation technique coupled with Atomic Fluorescence Spectrometry is widely used for low content elements in plant sample. The new technique, Laser-induced Breakdown Spectroscopy, is also used for plant sample without complex pretreatment, can on-line and on-site simultaneously determine multi-elements with simple and fast operation. Other high selective and sensitive techniques are also vital to determine unusual inorganic elements in plant sample. Based on the previous research, it pointed out that the solid sampling technique is a new development trend for inorganic element analysis in plant sample.