Magnetic molecularly imprinted polymers for the determination of ß-agonist residues in milk by ultra high performance liquid chromatography with tandem mass spectrometry.

A simple, accurate, and highly sensitive analytical method was developed in this study for the determination of nine ß-agonists in milk. In this method, a new magnetic adsorbent of molecularly imprinted polymers/magnetic nanoparticles prepared by simple physical blending was adopted, which enabled magnetic solid-phase extraction. Thus, the resultant material can be separated from the solvent rapidly and conveniently by a magnet. Two kinds of molecularly imprinted polymer/magnetic nanoparticles materials were fabricated, and the characteristics of materials such as the ratio, pH, amount, desorption, and regeneration were investigated. The analytes were quantified by ultra high performance liquid chromatography coupled to an electrospray ionization tandem mass spectrometer operating in multiple reaction monitoring modes. The detection limit of the method was 0.003-0.3 µg/L, and the detection capability was 0.01-0.3 µg/L. The recoveries of these compounds were 65.7-114% at three spiked levels. Reproducibility represented by relative standard deviation was 11.2% or less. The method was successfully applied to the screening of real samples obtained from local markets and confirmation of the suspected target analytes.

Metabolite of chiral cycloxaprid in solvent and in the raw of Puer tea.

Cycloxaprid (CYC) with a chiral oxabridged cis- structure contains a pair of enantiomers. Enantioselective degradation, transformation and metabolite of CYC was performed in different solvents under light and raw Puer tea processing. The results showed that cycloxaprid enantiomers in acetonitrile and acetone was stable over 17 day, however the transformation of 1S, 2R-(-)-cycloxaprid or 1R, 2S-(-)-cycloxaprid was founded in methanol. The fastest degradation of cycloxaprid occurred in acetone under light, the metabolites were founded with retention times (TR) at 34.83, 15.78 min, which mainly was via the reduce reaction of NO2 to NO, and rearrange reaction to tetrahydropyran. Degradation pathways were via the cleavage of the oxabridge seven member ring and the whole C ring. However, the degradation pathway under raw Puer tea processing was via the cleavage of whole C ring and the cleavage of oxabridge seven member ring and reducing NO2, then it underwent an elimination of nitromethylene and rearrange reaction. This pathway of Puer tea processing was firstly founded.

The evaluation of the nutritional quality of common wild edible fungi in Yunnan Province.

There are huge resource reserves of wild edible fungi richer in their varieties in Yunnan Province which is located on plateau of low latitude and possesses unique various climate environments and bigger vegetative cover ratios. Moreover, nutrients and flavor substances in the same or various species of wild edible fungi differ greatly with the influence on different components from habitats and geographic areas. So, 5 common wild edible fungi were collected from different areas in Yunnan Province, and several findings were made from this research. Above all, through the evaluation of amino acids, these 5 fungi met the criteria for ideal protein by WHO/FAO, and the nutritional value of protein was ranked as matsutake > truffle > collybia albuminosa > bolete > chanterelle. Next, after the analysis of taste activity values, the ranking of taste was bolete > collybia albuminosa > truffle > matsutake > chanterelle. Subsequently, the ranking of characters was truffle > collybia albuminosa >bolete > matsutake > chanterelle through principal component analysis. Finally, truffle could be completely divided by Fisher discrimination analysis with a bigger difference from others, main in ash, protein, sugar, and polysaccharide, meanwhile, truffle and bolete could be completely divided by orthogonal projections to latent structures discrimination analysis, main in protein, crude fiber, fat, and amino acid. So, there was a more conspicuous difference in nutrients among fungi, through which nutrients combined with multivariate statistics analysis made possible the correct differentiation of small range categories in wild edible fungi, and the correct classification of small range of them could effectively be realized.

Determination of trigonelline, nicotinic acid, and caffeine in Yunnan Arabica coffee by microwave-assisted extraction and HPLC with two columns in series.

A simple, rapid method was developed for simultaneous extraction of trigonelline, nicotinic acid, and caffeine from coffee, and separation by two chromatographic columns in series. The trigonelline, nicotinic acid, and caffeine were extracted with microwave-assisted extraction (MAE). The optimal conditions selected were 3 min, 200 psi, and 120 degrees C. The chromatographic separation was performed with two columns in series, polyaromatic hydrocarbon C18 (250 x 4.6 mm id, 5 microm particle size) and Bondapak NH2 (300 x 3.9 mm id, 5 microm particle size). Isocratic elution was with 0.02 M phosphoric acid-methanol (70 + 30, v/v) mobile phase at a flow rate of 0.8 mL/min. Good recoveries and RSD values were found for all analytes in the matrix. The LOD of the three compounds was 0.02 mg/L, and the LOQ was 0.005% in the matrix. The concentrations of trigonelline, nicotinic acid, and caffeine in instant coffee, roasted coffee, and raw coffee (Yunnan Arabica coffee) were assessed by MAE and hot water extraction; the correlation coefficients between concentrations of the three compounds obtained were close to 1.

Fast separation ultra-performance liquid chromatography for determination of pre-column derivative abamectin and ivermectin residues in vegetable.

A new residue method for quantification of abamectin and ivermectin in vegetable is described in the article. The derivative process is devised that acylating chemical is firstly performed by N-methylimidazole (MI) and trifluoroacetic anhydride (TFAA), then which reacted with hydroxyl function of abamerctin to make fluorescence. The influence of triethylamin (TEA) is examined. Separation is resolute by a short column of 1.7 µm size and operated at high pressure values (10.000 psi). The optimal chromatographic condition and the highest sensitivity are achieved by acetonitrile: water (95: 5), 0.4 mL/min, 0.2 µL injector. The detection limits of abamectin and ivermectin are 1 µg/kg respectively.

Microwave-assisted hydrolysis of lutein and zeaxanthin esters in marigold (Tagetes erecta L.).

Saponification of lutein and zeaxanthin was performed by microwave-assisted hydrolysis (MAH) and analysed by ultra performance liquid chromatography. The optimal condition of MAH was studied, and the degradation or isomerization of lutein and zeaxanthin were estimated under MAH. The concentrations of lutein and zeaxanthin in 20 marigold samples were assessed by saponification using traditional heater and MAH, the regression coefficient of lutein obtained by two methods was 0.9688 and that of zeaxanthin was 0.9527. The limit of detection for lutein and zeaxanthin was 0.05 and 0.1 µg/ml, respectively, and the limit of quantification for lutein and zeaxanthin was 0.05 mg/100 g and 0.1 mg/100 g, respectively.

The level variation of Nε-(carboxymethyl)lysine is correlated with chlorogenic acids in Arabica L. Coffee beans under different process conditions.

Nε-(carboxymethyl) lysine (CML) is universally used as a marker of the occurrence of advanced glycation end products (AGEs) in foods. This study investigated the level changes of CML, chlorogenic acids (CQAs), lysine (Lys), fat and pH in coffee during roasting. The CML level went up slowly in the first 10 mins, then declined sharply during the next 2 mins, and kept increasing constantly in the following baking time, while the lowest CML level was obtained by roasting at 235 °C for 12 mins. The three CQAs isomers had different efficacy in affecting the levels of CML and other factors, indicating the CQAs isomers may play an important role in influencing the CML level. So it might be possible to regulate the formation of CML and gain better coffee quality via adjusting the levels of CQAs in baking process. This study provided important enlightenment on CML control during coffee baking.

A magnetic multi-walled carbon nanotube preparative method for analyzing asymmetric carbon, phosphorus and sulfur atoms of chiral pesticide residues in Chinese herbals by chiral liquid chromatography-quadrupole/linear ion trap mass spectrometry determination.

An analytical method for the determination of asymmetric carbon, phosphorus and sulfur atoms in chiral pesticide residues by magnetic multi-walled carbon nanotube sample pretreatment combined with chiral ultra-performance liquid chromatography/quadrupole/linear ion trap mass spectrometry (UPLC-MS/Qtrap) was developed and applied to chiral pesticide residues analysis in Chinese herbals. Eleven different chiral pesticides were found, and 36.4% were positive in Chinese herbals. Three plants containing detectable pesticide residues were observed in Dendrobium nobile, Panax notoginseng flowers and honeysuckle, in the order of decreasing detected concentration. High detection frequencies of 26.1% for (R/S)-(±)-difenoconazole and 14.5% for (R/S)-(±)-metalaxyl and (R/S)-(±)-propiconazole were observed, the residual amount for (R/S)-(±)-difenoconazole, (R/S)-(±)-metalaxyl and (R/S)-(±)-propiconazole were 0.32 ~ 2.5 mg/kg, 0.022 ~ 0.23 mg/kg, 0.62 ~ 3.21 mg/kg respectively. The EF value of (R/S)-(±)-difenoconazole was 0.506 ± 0.046. The EF value of (R/S)-(±)-metalaxyl was lower than 0.5 in Dendrobium nobile, Panax notoginseng flowers, Panax notoginseng roots and hawthorn. The EF of (R/S)-(±)-propiconazole was not significantly enantioselective in honeysuckle and Panax notoginseng flowers. The enantioselectivity of various pesticide residues in different plants cannot be predicted from our existing knowledge and may closely depend on plant growth, environmental conditions or molecular structure.

Development and Validation of Multiclass Chiral Pesticide Residues Analysis Method in Tea by QuEChERS Combined Liquid Chromatography Quadruple-Linear Ion Trap Mass Spectrometry.

BACKGROUND: No single pure enantiomeric pesticide residues was investigated and set regulations for tea quality safety and risk assessment. OBJECTIVE: Due to lack of chiral pesticide analysis method and data, the Maximum residue limits (MRLs) about the chiral pesticides in tea was unknown. METHOD: An analytical method for the determination of chiral pesticide residues by QuEChERS combined chiral liquid chromatography quadruple/linear ion trap mass spectrometry (LC-MS/MS-Qtrap) was developed and applied to the analysis of various teas. RESULTS: The mean recoveries for pesticides enantiomers ranged from 75.9% to 112.4%. Reproducibility represented by relative standard deviation percentage was 10% or less. Good linearity was achieved for all enantiomers with determination coefficients (r2) greater than 0.99. The detection of limit (CCα) and quantification of limit (CCß) were 0.2 ∼1 µg/kg and 0.5∼5 µg/kg, respectively. CONCLUSIONS: The method was suitable for monitoring the enantiomeric pesticide residues in various teas. HIGHLIGHTS: Enantioselective multiclass pesticide residues were determined in various teas by LC-MS/MS-Qtrap, additional Qtrap scan functions greatly enhance the performance of screening, confirmation, and identification of chiral pesticides.

Nonstereoselective dissipation of sulfoxaflor in different Puer tea processing.

The stereoisomer behavior of sulfoxaflor was investigated by liquid chromatography-tandem mass spectrometry (LC-MS/MS) during raw Puer tea, ripen Puer tea, and sun-dry Puer tea processing. The persistence of sulfoxaflor stereoisomers was consistently prolonged with different Puer tea processing from sun-dry Puer tea, ripen Puer tea to raw Puer tea with t 1/2 4.0-4.2 hr (sun-dry Puer tea) to 6.21-7.04 months (raw Puer tea). Three fermentation temperature in ripen Puer tea shown that the sulfoxaflor residue was easy to degrade under low fermentation temperature (37°C). It implied that enzyme catalysis may play an important role in degradation of sulfoxaflor. The no-enantioselective dissipation of sulfoxaflor was found in different Puer tea processing.

[Correlation of mineral elements between milled and brown rice and soils in Yunnan studied by ICP-AES].

In the present paper, the contents of 18 mineral elements in milled and brown rice of 55 accessions elite cultivars as well as corresponding soils were determined by ICP-AES technique. The method proves to be simple, rapid, highly sensitive and accurate, and can be used to determine many elements at the same time, its recovery ratio obtained by standard addition method ranged between 93.1% and 110.2%, and its RSD was from 0.8% to 5.1%. The analytical results showed that 18 mineral elements (S, Mo, Ba, Ni, Fe, Cr, Na, Al, Cu, P, Sn, Zn, B, Mn, Mg, Ca, Sr and K) are the important active compositions of functional rice, and their mean contents in milled rice are in the order of P>K>S>Mg>Ca>Zn>Na>Al>Mn>Fe>Cu>B >Mo>Ni>Sn>Cr>Ba>Sr, in brown rice in the order of P>K>Mg>S>Ca>Zn>Mn>Al>Na>Fe>Cu>B>Mo>Sn> Ni>Cr>Ba>Sr, but in soil in the order of Fe>Al>Ca>K>Mg>P>S>Mn>B>Na>Ba>Zn>Cr>Cu>Ni>Sn>Mo> Sr; 16 mineral elements in milled and brown rice (except for S and P) are clearly lower than that in soils. The correlation of 8 microelements (Mo, Ni, Cr, Sr, Mn, Zn, Cu and Na) in milled and brown rice is closer than that of 6 macroelements (P, K, Mg, Ca, S and Al). There are rich Fe, Al and Ca in Yunnan soils, but 4 elements (P, K, Mg and S) are in high priority in milled and brown rice; The milled rice used for the staple is easier to place a premium on chronics than brown rice. The above results provided reliable data and theory bases for genetic breeding and production of functional rice, and for further solving the chronics and the malnourished problems with insufficient Fe, Zn and Ca for 4 billion people in the world.

A Simple Method for the Screening and Measurement of Phenols in Dendrobium chrysotoxum by a Miniature Mass Detector Using a Matrix Solid-Phase Dispersion Method.

The present study aims at building a miniature mass method for the simultaneous determination of 12 phenols including the subtypes of bibenzyl, phenanthrene, and fluorenone, which was used to evaluate the quality of Dendrobium chrysotoxum. Through the full scan mode, new compounds were elucidated. The new compounds were quantified by carrying out the analysis of the ratio of the standard solution areas to new compound areas versus analyte concentration. The limit of detection (LOD) and limit of quantification (LOQ) for phenols were 0.5 µg/mL-1 µg/mL and 1 µg/mL-2 µg/mL, respectively. Average recoveries of phenols were ranged from 83.2% to 97.5%. Reproducibility represented by the RSD percentage was from 2.3% to 8.7%. The average content of the four analytes, erianin, chrysotobibenzyl, confusarin, and moscatilin, were more than 200 mg/kg, and the content of bibenzyl compounds was found to be the highest in Dendrobium chrysotoxum. Among these bibenzyl compounds, erianin was determined as the typical chemical marker from Dendrobium chrysotoxum. The newly established UPLC with a miniature mass detector method was found to be an appropriate tool for the quality assessment of Dendrobium chrysotoxum.

The rapid determination of artemisinin by post-column derivatization high-performance liquid chromatography using matrix solid-phase dispersion method.

Artemisinin (an antimalaric compound) is isolated as the active compound of the medicinal plant Artemisia annua L. A simple, rapid, and high-efficient method of extraction is developed, in which it is extracted by matrix solid-phase dispersion (MSPD) and directly analyzed by post-column derivatization high-performance liquid chromatography (HPLC). The quantitation results from the MSPD method are compared with two conventional liquid solvent extraction processes, Soxhlet and ultrasonic wave by F-test, and the result indicates no significant difference. The production rate of Artemisinin during wild plant growth (tested over two years, acquired from Yunnan, provincial Yuan Yan country) is determined. The recovery range of determination is 88.1-91.2%. The relative standard deviation (RSD) is 4.55-6.43%. The limits of detection are 0.1 microg/mL, and the limits of quantitation are 0.5 microg/mL.

[Determination of mineral elements in brown rice of near-isogenic lines population for Japonica rice by ICP-AES].

In the present paper, the contents of 17 mineral elements (S, Mo, Ni, Fe, Cr, Na, Al, Cu, P, Sn, Zn, B, Mn, Mg, Ca, Sr and K) in brown rice of 264 plant lines in near-isogenic lines (NILs) population and parents for Japonica rice were determined by ICP-AES technique. The method proved to be simple, rapid, highly sensitive and accurate, and can be used to determine many elements at the same time. Its recovery ratio obtained by standard addition method ranged between 92.3% and 110.27%, and its RSD was lower than 6%. The analytical results showed that NILs for various mineral elements based on the BC5F5 population consisting of 261 lines were developed from a cross between NIL (BC4F5) and Towada. To our knowledge, this is the first report on that near-isogenic lines NIL(BC4F5) with the important value for high mineral elements associated with cold tolerance at booting stage have been bred. The results of the determination show that the brown rice is rich in eleven elements such as P, K, Mg, S, Ca, Zn, Mn, Na, Fe, Cu and Al necessary to human health. There is smaller variation of 5 macroelements (11.15%-16.45%) but larger variation of 12 microelements (16.57%-94.96%) in brown rice from populations. There is significant correlation among 95 from 136 pairs in 17 elements, moreover, especially the correlation (0.531**-0.921**) among 15 pairs of six micro-elements (Mo, Ni, Al, Sn, Cr and Sr) associated with the active components of functional rice is relatively higher than that of 10 pairs (0.175**-0.867**) of 5 macroelements (P, K, Ca, Mg and S), revealing the importance of microelements to catalysing and synthesizing the active components of functional rice. The above results provided reliable data and theory bases for gene location and cloning of controlling elements contents in brown rice, and further revealed the molecular and physiological mechanism of the relation between mineral elements in brown rice and cold tolerance at booting stage in japonica rice from Yunnan Province of China.

Halogenated and parent polycyclic aromatic hydrocarbons in vegetables: Levels, dietary intakes, and health risk assessments.

Halogenated polycyclic aromatic hydrocarbons (HPAHs) are attracting increasing concern because of their greater toxicity than their corresponding parent PAHs. However, human exposure to HPAHs via food consumption is not fully understood. In this study, daily intake via vegetable ingestion of 11 HPAHs and 16 PAHs and subsequent cancer risk were assessed for population in Beijing. A total of 80 vegetable samples were purchased from markets, including five leafy vegetables and three root vegetables. The concentrations of total HPAHs (∑HPAHs) were 0.357-0.874ng/g in all vegetables, lower than that of total PAHs (∑PAHs, 10.6-47.4ng/g). ∑HPAHs and ∑PAHs concentrations in leafy vegetables were higher than those in root vegetables, suggesting that the atmospheric deposition might be the dominant source of PAHs and HPAHs in leafy vegetables. Among the HPAH congeners, 2-BrFle and 9-ClFle were the predominant compounds and frequently detected in the vegetable samples. HPAHs and PAHs were also found in certificated vegetables at the concentrations of 0.466-0.751ng/g and 10.6-38.9ng/g, respectively, which were lower than those in non-certificated vegetables except for spinach. For leafy vegetables from local farms, the ∑PAHs and ∑HPAHs levels in the rape and Chinese cabbage samples significantly decreased with increasing the distance away from the incineration plant. The incremental lifetime cancer risks of HPAHs were below the acceptable risk level (10-6), suggesting that there might be little or no risk to consumers from these compounds in vegetables. For all population groups, children were the most sensitive population to PAHs and HPAHs, and their health issues should be paid more attention.

Capillary gas chromatographic determination of dimethachlon residues in fresh tobacco leaves and cut-tobacco.

Simple procedures for extraction and chromatographic determination of dimethachlon residues in fresh tobacco leaves and cut-tobacco are described. The determination was carried out by capillary gas chromatography (GC) with electron capture detection (ECD) and confirmed by GC-MS. The mean recoveries and relative standard deviation (RSD) were 93.2%~112.9% and 3.5%~6.7%, respectively at levels ranging from 0.01 to 0.1 mg/kg. The limit of determination was 0.001 mg/kg. Tobacco samples in routine check were successfully analyzed using the proposed method.

Simultaneous determination of anabolic steroids and ß-agonists in milk by QuEChERS and ultra high performance liquid chromatography tandem mass spectrometry.

A simple, accurate and highly sensitive multiresidues method was developed for the determination of 9 anabolic steroids and 16 ß-agonists in milk. Target compounds were extracted and separated by a modified QuEChERS (Quick, Easy, Cheap, Effective, Rugged, Safe) method with Primary secondary amine (PSA) and Zinc oxide (ZnO) nanoparticles as adsorbents. The analytes were determined by ultra high performance liquid chromatography coupled to an electro-spray ionization tandem mass spectrometer (UHPLC-MS/MS) operating in negative/positive multiple reaction monitoring mode. The effect of QuEChERS including organic solvent, amount of ZnO nanoparticle was evaluated. Good linearity was obtained for the analytes in the concentration range of 0.1-200µg/L with a correlation coefficients higher than 0.994. Decision limits (CCα) was from 0.007µg/kg-0.1µg/kg, and detection capabilities (CCß) was in the range of 0.02-0.4µg/kg. The recoveries of these compounds were between 63% and 126% at three fortified levels. Reproducibility represented by RSD was with 10% or less. The method was successfully applied to screening of real milk samples obtained from local markets and confirmation of the suspected target analytes.

[Determination of six amide herbicide residues in soil by QuEChERS-gas chromatography-mass spectrometry].

A method was developed for the determination of six amide herbicides, such as acetochlor, alachlor, metolachlor, metazachlor, butachlor and pretilachlor, by QuEChERS-gas chromatography-mass spectrometry. The soil samples were extracted by 10 mL acetonitrile, 10 mL deionized water and 4 g sodium chloride, then purified with 50 mg N-propyl ethylenediamine (PSA), 50 mg C18, 10 mg graphitized carbon black (GCB) and 100 mg MgSO4. Low-polar silica capillary column HP-5MS was used. The extracts were detected by electron impact ionization (EI) source in the selected ion monitoring (SIM) mode. The results showed that good linearities were obtained with the mass concentrations of the six amide herbicides in the range of 0.01-1.00 mg/L, and their correlation coefficients ranged from 0.9996 to 1.0000. Under the condition of adding contents of 0.025, 0.10 and 0.50 mg/kg, the average recoveries of the six amide herbicides ranged from 92.0% to 108%, and the relative standard deviations were 1.64%-8.25%. The limits of detection (LODs) were 0.002-0.006 mg/kg and the limits of quantification (LOQs) were 0.005-0.02 mg/kg. Comparing with the gas chromatography-electron capture detection (GC-ECD) which used to detect the amide herbicides, this method can improve the anti-interference ability, and get better separation of the six amide herbicides. The method has the advantages of simplicity, rapidity, and application value.

Illumina-based transcriptomic profiling of Panax notoginseng in response to arsenic stress.

BACKGROUND: Panax notoginseng, a famous herbal medicine, has recently attracted great attention on its safety and quality since P. notoginseng can accumulate and tolerate As from growing environment. For the purpose of understanding As damage to the quality of P. notoginseng as well as corresponding tolerance mechanisms, genes involved in As stress response were identified using Illumina sequencing. RESULTS: Totally 91,979,946 clean reads were generated and were de novo assembled into 172,355 unigenes. A total of 81,575 unigenes were annotated in at least one database for their functions, accounting for 47.34 %. By comparative analysis, 1725 differentially expressed genes (DEGs, 763 up-regulated/962 down-regulated) were identified between As stressed plant (HAs) and control plant (CK), among which 20 DEGs were further validated by real-time quantitative PCR (qRT-PCR). In the upstream and downstream steps of biosynthesis pathways of ginsenosides and flavonoids, 7 genes encoding key enzymes were down-regulated in HAs. Such down-regulations were also revealed in pathway enrichment analysis. Genes encoding transporters (transporters of ABC, MATE, sugar, oligopeptide, nitrate), genes related to hormone metabolism (ethylene, ABA, cytokinin) and genes related to arsenic accumulation (HXT, NRAMP, MT and GRX) were differentially expressed. The up-regulated genes included those of oxidative stress-related protein (GSTs, thioredoxin), transcription factors (HSFs, MYBs) and molecular chaperones (HSP). CONCLUSIONS: The down-regulation of biosynthesis of ginsenoside and flavonoid indicated that As accumulation in P. notoginseng can cause not only safety hazard, but also qualitative losses. Aside from the results of arsenic content of seedling roots, the ability of P. notoginseng to over-accumulate arsenic can also be explained by the differential expression of genes of HXT, NRAMP, MT and GRX. To illustrate the detoxification mechanism of P. notoginseng, differential expression of genes encoding oxidative-related proteins, transcription factors, molecular chaperones, transporters and hormone were revealed in our study, which agreed with those reported in Arabidopsis to a certain extent, indicating P. notoginseng and Arabidopsis shared some common detoxification mechanisms in response to As stress. The longer As treatment in our study may account for the smaller quantity of related DEGs and smaller degree of expression differences of certain DEGs compared with those of Arabidopsis.

Reduction, methylation, and translocation of arsenic in Panax notoginseng grown under field conditions in arsenic-contaminated soils.

Variations in arsenic (As) species in Panax notoginseng grown under field conditions remain understudied compared with those under greenhouse conditions. In the present study, soil and plant samples were collected from Wenshan Zhuang and Miao Autonomous Prefecture, Yunnan Province, which is the main production area of P. notoginseng in China, to identify As species in the soil and plant tissues and further assess effect of As toxic stress on As transformation and translocation in P. notoginseng. The results showed that arsenate (As(V)) was almost exclusively identified in the soil, while arsenite (As(III)) and monomethylarsonic acid (MMA) were detected in high proportions in plant tissues, suggesting that As(V) could be reduced and subsequently methylated in the plant body, mainly in the root. The reduction and methylation of As in the root of P. notoginseng were promoted by low As toxic stress, but were impeded by high As toxic stress. Arsenic(III) and MMA could rapidly translocate upwards in P. notoginseng. In addition, the translocation of total As, As(III), and MMA from the root to the rhizome was a response to As toxic stress, and the translocation rate increased with the increasing As concentration in the taproot. This study provides new insights into the detoxification mechanism of P. notoginseng grown in As-contaminated soils and the control of As during cultivation.