Organoarsenic compounds in plants and soil on top of an ore vein

Plants and soil collected above an ore vein in Gasen (Austria) were investigated for total arsenic concentrations by inductively coupled plasma mass spectrometry (ICP‐MS). Total arsenic concentrations in all samples were higher than those usually found at non‐contaminated sites. The arsenic concentration in the soil ranged from ∼700 to ∼4000 mg kg⁻¹ dry mass. Arsenic concentrations in plant samples ranged from ∼0.5 to 6 mg kg⁻¹ dry mass and varied with plant species and plant part. Examination of plant and soil extracts by high‐performance liquid chromatography–ICP‐MS revealed that only small amounts of arsenic (<1%) could be extracted from the soil and the main part of the extractable arsenic from soil was inorganic arsenic, dominated by arsenate. Trimethylarsine oxide and arsenobetaine were also detected as minor compounds in soil. The extracts of the plants (Trifolium pratense, Dactylis glomerata, and Plantago lanceolata) contained arsenate, arsenite, methylarsonic acid, dimethylarsinic acid, trimethylarsine oxide, the tetramethylarsonium ion, arsenobetaine, and arsenocholine (2.5–12% extraction efficiency). The arsenic compounds and their concentrations differed with plant species. The extracts of D. glomerata and P. lanceolata contained mainly inorganic arsenic compounds typical of most other plants. T. pratense, on the other hand, contained mainly organic arsenicals and the major compound was methylarsonic acid. Copyright © 2002 John Wiley & Sons, Ltd.     

Speciation and health risk considerations of arsenic in the edible mushroom Laccaria amethystina collected from contaminated and uncontaminated locations

Samples of the edible mushroom Laccaria amethystina, which is known to accumulate arsenic, were collected from two uncontaminated beech forests and an arsenic-contaminated one in Denmark. The total arsenic concentration was 23 and 77 μg As g⁻¹ (dry weight) in the two uncontaminated samples and 1420 μg As g⁻¹ in the contaminated sample. The arsenic species were liberated from the samples using focused microwave-assisted extraction, and were separated and detected by anion- and cation-exchange high-performance liquid chromatography with an inductively coupled plasma mass spectrometer as arsenic-selective detector. Dimethylarsinic acid accounted for 68–74%, methylarsonic acid for 0.3–2.9%, trimethylarsine oxide for 0.6–2.0% and arsenic acid for 0.1–6.1% of the total arsenic. The unextractable fraction of arsenic ranged between 15 and 32%. The results also showed that when growing in the highly arsenate-contaminated soil (500–800 μg As g⁻¹) the mushrooms or their associated bacteria were able to biosynthesize dimethylarsinic acid from arsinic acid in the soil. Furthermore, arsenobetaine and trimethylarsine oxide were detected for the first time in Laccaria amethystina. Additionally, unidentified arsenic species were detected in the mushroom. The finding of arsenobetaine and trimethylarsine oxide in low amounts in the mushrooms showed that synthesis of this arsenical in nature is not restricted to marine biota. In order to minimize the toxicological risk of arsenic to humans it is recommended not to consume Laccaria amethystina mushrooms collected from the highly contaminated soil, because of a genotoxic effect of dimethylarsinic acid observed at high doses in animal experiments. © 1998 John Wiley & Sons, Ltd. No Abstract.     

Identification of extracellular arsenical metabolites in the growth medium of the microorganisms apiotrichum humicola and scopulariopsis brevicaulis

The separation and identification of some of the arsenic species produced in cells present in the growth medium when the microorganisms Apiotrichum humicola (previously known as Candida humicola) and Scopulariopsis brevicaulis were grown in the presence of arsenicals were achieved by using hydride generation–gas chromatography–atomic absorption spectrometry methodology (HG GC AA). Arsenite, monomethylarsonate, dimethylarsinate and trimethylarsine oxide were detected following incubation with arsenate. With arsenite as a substrate, the metabolites were monomethylarsonate, dimethylarsinate and trimethylarsine oxide; monomethylarsonate afforded dimethylarsinate and trimethylarsine oxide, and dimethylarsinate afforded trimethylarsine oxide. Trimethylarsine was not detected when the arsenic concentration was 1 ppm.     

Comparison of mild extraction procedures for determination of arsenic compounds in different parts of pepper plants (Capsicum annum,L.)

Eight extraction agents (water, methanol–water mixtures in various ratios, methanol, a 20 mmol l^?1 ammonium phosphate buffer, and a methanol–phosphate buffer) were tested for the extraction of arsenic compounds from fruits, stems + leaves, and roots of pepper plants grown on soil containing 17.2 mg kg^?1 of total arsenic. The arsenic compounds in the extracts were determined using high‐performance liquid chromatography–hydride generation inductively coupled plasma mass spectrometry. Whereas pure water was the most effective extraction agent for fruits (87 ± 3.3% extraction yield) and roots (96 ± 0.6% extraction yield), the 20 mM ammonium phosphate buffer at pH 6 extracted about 50% of the arsenic from stems + leaves. Decreasing extractability of the arsenic compounds was observed with increasing methanol concentrations for all parts of the pepper plant. In pepper fruits, arsenic(III), arsenic(V), and dimethylarsinic acid (DMA) were present (25%, 37%, and 39% respectively of the extractable arsenic). Arsenic(V) was the major compound in stems + leaves and roots (63% and 53% respectively), followed by arsenic(III) representing 33% and 42% respectively, and small amounts (not exceeding 5%) of DMA and methylarsonic acid were also detected. Hence, for a quantitative extraction of arsenic compounds from different plant tissues the extractant has to be optimized individually. Copyright © 2005 John Wiley & Sons, Ltd.     

Methylated arsenic species in estuarine porewaters

Inorganic arsenic, monomethylarsenic and dimethylarsenic species have been observed in samples of sediment porewater collected from the Tamar Estuary in South-West England. Porewater samples were collected using in situ dialysis. The arsenic species were separated by hydride generation and concentrated by liquid nitrogen trapping, prior to analysis by directly coupled gas chromatography-atomic absorption spectroscopy. The predominant dissolved arsenic species present was inorganic arsenic (5-62 m?g dm^?3). However, this is the first time significant concentrations of methylated arsenic species have been quantified in estuarine porewaters (0.04–0.70 m?g dm^?3), accounting for between 1 and 4% of the total dissolved arsenic. The presence of methylated arsenic compounds in porewaters is attributed to in situ environmental methylation, although the possibility of methylated arsenic species being derived from biological debris cannot be excluded.     

Urinary arsenic species in an arsenic‐affected area of West Bengal,India (part III)

Arsenic contamination of groundwater has long been reported in the Mushidabad district of West Bengal, India. We visited 13 arsenic‐affected families in the Makrampur village of the Beldanga block in Mushidabad during 18–21 December 2001 and collected five shallow tubewell‐water samples used general household purposes, four deep tubewell‐water samples used for drinking and cooking purposes, and 44 urine samples from those families. The arsenic concentrations in the five shallow tubewell‐water samples ranged from 18.0 to 408.4 ppb and those in the four deep tubewell‐water samples were from 5.2 to 9.6 ppb. The average arsenite (arsenic(III)), dimethylarsinic acid (DMA), monomethylarsonic acid (MMA) and arsenate (arsenic(V)) in urine were 28.7 ng mg^?1, 168.6 ng mg^?1, 25.0 ng mg^?1 and 4.6 ng mg^?1 creatinine respectively. The average total arsenic was 227.0 ng mg^?1 creatinine. On comparison of the ratio of (MMA + DMA) to total arsenic, the average proportion was 86.7 ± 9.2% (mean plus/minus to residual standard deviation, n = 43). The exception was data for one boy, whose proportion was 8.0%. One woman excreted the highest total arsenic, at 2890.0 ng mg^?1 creatinine. When using 43 of the urine samples (the exception being the one sample obtained from the boy) there were significantly positive correlations (p < 0.01) between arsenic(III) and MMA, between arsenic(III) and DMA and between MMA and DMA. Copyright © 2005 John Wiley & Sons, Ltd.     

Arsenic speciation in some environmental samples: a comparative study of HG–GC–QFAAS and HPLC–ICP–MS methods

Some water and soil extracts polluted with arsenic, and a sewage sludge certified for total arsenic have been analysed by high‐performance liquid chromatography–inductively coupled plasma–mass spectrometry (HPLC–ICP–MS) and hydride generation–gas chromatography– quartz furnace atomic absorption spectrometry (HG–GC–QFAAS techniques.) Detection limits in the range of 200–400 and 2–10 ng l⁻¹ respectively allowed the determination of inorganic [As(III), As(V)] and methylated (DMA, MMA, TMAO) arsenic species present in these samples. Results obtained by both methods are well correlated overall, whatever the arsenic chemical form and concentration range (8–10 000 μg l⁻¹). Comparison of these results enabled us to point out features and disadvantages of each analytical method and to reach a conclusion that they are suitable for arsenic speciation in these environmental matrices. Copyright © 2000 John Wiley & Sons, Ltd.     

Bioaccumulation and excretion of arsenic compounds by a marine unicellular alga,polyphysa peniculus

Polyphysa peniculus was grown in artificial seawater in the presence of arsenate, arsenite, monomethylarsonate and dimethylarsinic acid. The separation and identification of some of the arsenic species produced in the cells as well as in the growth medium were achieved by using hydride generation–gas chromatography–atomic absorption spectrometry methodology. Arsenite and dimethylarsinate were detected following incubation with arsenate. When the alga was treated with arsenite, dimethylarsinate was the major metabolite in the cells and in the growth medium; trace amounts of monomethylarsonate were also detected in the cells. With monomethylarsonate as a substrate, the metabolite is dimethylarsinate. Polyphysa peniculus did not metabolize dimethylarsinic acid when it was used as a substrate. Significant amounts of more complex arsenic species, such as arsenosungars, were not observed in the cells or medium on the evidence of flow injection–microwave digestion–hydride generation–atomic absorption spectrometry methodology. Transfer of the exposed cells to fresh medium caused release of most cell–associated arsenicals to the surrounding environment.     

Arsenic Compounds in Higher Fungi

In 50 mushroom species (56 samples) from Slovenia, Switzerland, Brazil, Sweden, The Netherlands and USA, total arsenic was determined by radiochemical neutron activation analysis (RNAA). Arsenic concentrations ranged from 0.1 to 30 μg g⁻¹ (dry mass). Arsenic compounds were determined in methanol extracts from the mushrooms by HPLC–ICP–MS. The aim of the study was not only to quantify arsenic compounds in mushrooms but also to uncover trends relating the methylating ability of a mushroom to its taxonomic or evolutionary status. The main arsenic compound found in many mushrooms (various puffballs, Agaricales and Aphyllophorales) was arsenobetaine. Arsenate [As(V)] was the main arsenic species in Laccaria fraterna and Entoloma rhodopolium and arsenite [As(III)] in Tricholoma sulphureum. A mixture of arsenite and arsenate was present in Amanita caesarea. Dimethylarsinic acid (DMA) and methylarsonic acid were present in many mushrooms, but generally as minor components. In Laccaria laccata, Leucocoprinus badhamii and Volvariella volvacea, DMA was the major metabolite. Arsenocholine (AC) and the tetramethylarsonium ion were present in a few species, generally at low concentrations, except for Sparassis crispa, in which AC was the main compound. Tri- methylarsine oxide was not found in any of the mushrooms. In some species small amounts of unknown compounds were also present. The possible taxonomic significance of the metabolite patterns and the predominance of arsenobetaine in more advanced fungal types are discussed. © 1997 John Wiley & Sons, Ltd.     

Comparison of mild extraction procedures for determination of plant-available arsenic compounds in soil

In this work three mild extraction agents for determination of plant-available fractions of elements in soil were evaluated for arsenic speciation in soil samples. Pepper (Capsicum annum, L.) var. California Wonder was cultivated in pots, and aqueous solutions of arsenite, arsenate, methylarsonic acid, and dimethylarsinic acid, at a concentration of 15 mg As kg^–1 soil, were added at the beginning of the experiment. Control pots (untreated) were also included. Deionized water, 0.01 mol L^–1 CaCl₂, and 0.05 mol L^–1 (NH₄)₂SO₄ were used to extract the plant-available fraction of the arsenic compounds in soil samples collected during the vegetation period of the plants. Whereas in control samples the extractable arsenic fraction did not exceed 1% of total arsenic content, soil amendment by arsenic compounds resulted in extraction of larger amounts, which varied between 1.4 and 8.1% of total arsenic content, depending on soil treatment and on the extracting agent applied. Among arsenic compounds determined by HPLC–ICPMS arsenate was predominant, followed by small amounts of arsenite, methylarsonic acid, and dimethylarsinic acid, depending on the individual soil treatment. In all the experiments in which methylarsonic acid was added to the soil methylarsonous acid was detected in the extracts, suggesting that the soil bacteria are capable of reducing methylarsonic acid before a further methylation occurs. No significant differences were observed between analytical data obtained by using different extraction procedures.     

Determination of arsenic compounds in marine mammals with high-performance liquid chromatography and an inductively coupled plasma mass spectrometer as element-specific detector

Total arsenic concentrations and the concentrations of individual arsenic compounds were determined in liver samples of pinnipeds [nine ringed seals (Phoca hispida), one bearded seal (Erginathus barbatus)] and cetaceans [two pilot whales (Globicephalus melas), one beluga whale (Deliphinapterus leucus)]. Total arsenic concentrations ranged from 0.167 to 2.40 mg As kg⁻¹ wet mass. The arsenic compounds extracted from the liver samples with a methanol/water mixture (9:1, v/v) were identified and quantified by anion- and cation-exchange chromatography. An ICP–MS equipped with a hydraulic high-pressure nebulizer served as the arsenic-specific detector. Arsenobetaine (0.052–1.67 mg As kg⁻¹ wet mass) was the predominant arsenic compound in all the liver samples. Arsenocholine was present in all livers (0.005–0.044 mg As kg⁻¹ wet mass). The tetramethylarsonium cation was detected in all pinnipeds ( < 0.009 to 0.043 mg As kg⁻¹) but not in any of the cetaceans. The concentration of dimethylarsinic acid ranged from < 0.001 to 0.109 mg As kg⁻¹ wet mass. Most of the concentrations for methylarsonic acid ( < 0.001 to 0.025 mg As kg⁻¹ wet mass) were below the detection limit. Arsenous acid and arsenic acid concentrations were below the detection limit of the method (0.001 mg As kg⁻¹). An unknown arsenic compound was present in all liver samples at concentrations from 0.002–0.027 mg As kg⁻¹. © 1998 John Wiley & Sons, Ltd.     

Arsenic compounds in terrestrial organisms. IV. Green plants and lichens from an old arsenic smelter site in Austria

Two lichens and 12 green plants growing at a former arsenic roasting facility in Austria were analyzed for total arsenic by ICP–MS, and for 12 arsenic compounds (arsenous acid, arsenic acid, dimethylarsinic acid, methylarsonic acid, arsenobetaine, arsenocholine, trimethylarsine oxide, the tetramethylarsonium cation and four arsenoriboses) by HPLC–ICP–MS. Total arsenic concentrations were in the range of 0.27 mg As (kg dry mass)⁻¹ (Vaccinium vitis idaea) to 8.45 mg As (kg dry mass)⁻¹ (Equisetum pratense). Arsenic compounds were extracted with two different extractants [water or methanol/water (9:1)]. Extraction yields achieved with water [7% (Alectoria ochroleuca) to 71% (Equisetum pratense)] were higher than those with methanol/water (9:1) [4% (Alectoria ochroleuca) to 22% (Deschampsia cespitosa)]. The differences were caused mainly by better extraction of inorganic arsenic (green plants) and an arsenoribose (lichens) by water. Inorganic arsenic was detected in all extracts. Dimethylarsinic acid was identified in nine green plants. One of the lichens (Alectoria ochroleuca) contained traces of methylarsonic acid, and this compound was also detected in nine of the green plants. Arsenobetaine was a major arsenic compound in extracts of the lichens, but except for traces in the grass Deschampsia cespitosa, it was not detected in the green plants. In contrast to arsenobetaine, trimethylarsine oxide was found in all samples. The tetramethylarsonium cation was identified in the lichen Alectoria ochroleuca and in four green plants. With the exception of the needles of the tree Larix decidua the arsenoribose (2′R)‐dimethyl[1‐O‐(2′,3′‐dihydroxypropyl)‐5‐deoxy‐β‐D ‐ribofuranos‐5‐yl]arsine oxide was identified at the low μg kg⁻¹ level or as a trace in all plants investigated. In the lichens an unknown arsenic compound, which did not match any of the standard compounds available, was also detected. Arsenocholine and three of the arsenoriboses were not detected in the samples. Copyright © 2000 John Wiley & Sons, Ltd.     

Methylation and Demethylation of Dimethylarsinic Acid in Rats Following Chronic Oral Exposure

Metabolites of dimethylarsinic acid (DMA) were studied in rats chronically exposed to DMA in drinking water. The urine was collected by forced urination at the end of 8, 20 and 30 weeks and the feces at the end of 30 weeks. The samples were analyzed for arsenic species by a combined system of ion chromatography and inductively coupled plasma mass spectrometry (IC–ICP–MS). Increases in arsenite, DMA, trimethylarsine oxide and a still-to-be-identified arsenic compound (which was eluted immediately after monomethylarsonic acid on the chromatogram) were detected in both urine and feces. At the 100 mg l⁻¹ dose, DMA was the main component in the urine; arsenite was a main component in the feces. The results indicate that, besides undergoing methylation, DMA can be demethylated to inorganic arsenic, and demethylation of DMA may be associated with intestinal bacteria     

Speciation of Arsenic Compounds in the Urine of Rats Orally Exposed to Dimethylarsinic Acid Ion Chromatography with ICP–MS as an Element-Selective Detector

A combined ion chromatography (IC) with inductively coupled plasma mass spectrometry (ICP—MS) system as an element-selective detector has been used for the determination of arsenic compounds. Seven arsenic compounds were separated by cation-exchange chromatography. Subsequently, the separated arsenic compounds were directly introduced into the ICP—MS and were detected at m/z =75. Detection limits for the seven arsenic compounds ranged from 0.8 to 3.8 μg As/l. The IC–ICP–MS system was applied to the determination of arsenic compounds in the urine of dimethylarsinic acid (DMAA)-exposed rats. DMAA was the most abundant arsenic compound detected. Arsenous acid, monomethylarsonic acid and trimethylarsine oxide were also detected.     

Influence of Microwave Blanching on Arsenic Speciation and Bioaccessibility in Lentinus Edodes

Humans are exposed to arsenic by inhalation and ingestion and are therefore may be affected by its toxicity. Arsenic may enter the human body by inhalation and ingestion. Cooking may alter the contents and chemical forms of arsenic. The determination of arsenic species in Lentinus edodes after microwave blanching was performed by high-performance liquid chromatography–inductively coupled plasma–mass spectrometry. Using a physiologically based extraction, the bioaccessibility of arsenic species in raw L. edodes and microwave blanching treated L. edodes were determined after the simulated gastrointestinal digestion. The arsenate (As^V), arsenite (As^III), monomethylarsonic acid (MMA), dimethylarsinic acid (DMA), arsenobetaine, and arsenocholine did not undergo decomposition and transformation in this study. Furthermore, the total contents of arsenic in L. edodes samples were in the range of 0.1378?±?0.0044–0.2347?±?0.0144?mg/kg. Approximately 3.38–43.27% were released from samples into the blanching water after various microwave blanching treatments. The oxidation of As^III and demethylation of DMA and MMA were observed in L. edodes during digestion, increasing the likelihood of arsenic toxicity in the liver. The health risk for arsenic in L. edodes was decreased after microwave blanching because the potentially available arsenic in microwave blanching treatments L. edodes samples (83.78?±?0.9103%) were lower than those in raw L. edodes samples (88.33?±?0.7983%). L. edodes subjected to microwave blanching prior to consumption significantly decreased the total arsenic content and the risk of arsenic exposure to consumers (p?相似文献   

Transformation of arsenic(V) by the fungus Fusarium oxysporum melonis isolated from the alga Fucus gardneri

A fungus isolated from the macroalga Fucus gardneri was identified by using 28S rDNA sequence analysis, 99% similarity match, as Fusarium oxysporum meloni. The fungus was exposed to arsenic(V) (500 ppb) in artificial seawater to investigate the possibility that the fungus is the source of the metabolic activity that results in the presence of arsenosugars in the macroalga. High‐performance liquid chromatography coupled with inductively coupled plasma mass spectrometry was used to identify the arsenic species in the fungus, and in the growth medium. The fungus was able to accumulate arsenic(V) and an increase in arsenite and dimethylarsinate was also observed. Some reduction of arsenate led to a small increase of arsenite in the growth medium. The fungus does not seem to be involved with the accumulation of arsenosugars by the Fucus. Copyright © 2002 John Wiley & Sons, Ltd.     

The identification of some water-soluble arsenic species in the marine brown algae Fucus distichus

The extraction and clean-up procedures developed to isolate the water-soluble arsenic species present in the marine macroalga Fucus distichus, from British Columbia, Canada, are described. The arsenic species were extracted into methanol and then subjected to gel-permeation and ion-exchange chromatography. Fractions high in arsenic were identified by using graphite furnace atomic absorption spectroscopy (GF-AAS), and further investigated by using high-performance liquid chromatography coupled to inductively coupled plasma–mass spectrometry (HPLC–ICP MS). By using different HPLC columns and mobile-phase conditions, the four major arsenic-containing compounds present in the macroalga were positively identified as arsenosugars; one minor compound remained unidentified. © 1997 John Wiley & Sons, Ltd.     

Rapid structural characterization of in vivo and in vitro metabolites of tinoridine using UHPLC–QTOF–MS/MS and in silico toxicological screening of its metabolites

Tinoridine is a nonsteroidal anti‐inflammatory drug and also has potent radical scavenger and antiperoxidative activity. However, metabolism of tinoridine has not been thoroughly investigated. To identify in vivo metabolites, the drug was administered to Sprague–Dawley rats (n = 5) at a dose of 20 mg kg^?1, and blood, urine and feces were collected at different time points up to 24 h. In vitro metabolism was delved by incubating the drug with rat liver microsomes and human liver microsomes. The metabolites were enriched by optimized sample preparation involving protein precipitation using acetonitrile, followed by solid‐phase extraction. Data processes were carried out using multiple mass defects filters to eliminate false‐positive ions. A total of 11 metabolites have been identified in urine samples including hydroxyl, dealkylated, acetylated and glucuronide metabolites; among them, some were also observed in plasma and feces samples. Only two major metabolites were formed using liver microsomal incubations. These metabolites were also observed in vivo. All the 11 metabolites, which are hitherto unknown and novel, were characterized by using ultrahigh‐performance liquid chromatography–quadrupole time‐of‐flight tandem mass spectrometry in combination with accurate mass measurements. Finally, in silico toxicological screening of all metabolites was evaluated, and two metabolites were proposed to show a certain degree of lung or liver toxicity. Copyright © 2015 John Wiley & Sons, Ltd.     

Preservation strategies for inorganic arsenic species in high iron,low-<Emphasis Type="Italic">Eh</Emphasis> groundwater from West Bengal,India

Despite the importance of accurately determining inorganic arsenic speciation in natural waters to predicting bioavailability and environmental and health impacts, there remains considerable debate about the most appropriate species preservation strategies to adopt. In particular, the high-iron, low-Eh (redox potential) shallow groundwaters in West Bengal, Bangladesh and SE Asia, the use of which for drinking and irrigation purposes has led to massive international concerns for human health, are particularly prone to changes in arsenic speciation after sampling. The effectiveness of HCl and EDTA preservation strategies has been compared and used on variably arsenic-rich West Bengali groundwater samples, analysed by ion chromatography–inductively coupled plasma–mass spectrometry (IC–ICP–MS). Immediate filtration and acidification with HCl followed by refrigerated storage was found to be the most effective strategy for minimizing the oxidation of inorganic As(III) during storage. The use of a PRP-X100 (Hamilton) column with a 20 mmol L^–1 NH₄H₂PO₄ as mobile phase enabled the separation of Cl^– from As(III), monomethylarsonic acid, dimethylarsinic acid and As(V), thereby eliminating any isobaric interference between ⁴⁰Ar³⁵Cl⁺ and ⁷⁵As⁺. The use of EDTA as a preservative, whose action is impaired by the high calcium concentrations typical of these types of groundwater, resulted in marked oxidation during storage. The use of HCl is therefore indicated for analytical methods in which chloride-rich matrices are not problematical. The groundwaters analysed by IC–ICP–MS were found to contain between 5 and 770 ng As mL^–1 exclusively as inorganic arsenic species. As(III)/total-As varied between 0 and 0.94.     

Multiresidue determination of 29 pesticide residues in pepper through a modified QuEChERS method and gas chromatography–mass spectrometry

This study describes the development and use of a modified quick, easy, cheap, effective, rugged and safe (QuEChERS) method coupled with gas chromatography with mass spectrometry to determine 29 pesticide residues in green, red and dehydrated red peppers. Pesticides were extracted with acetonitrile (1% acetic acid), partitioned with sodium chloride and purified with primary secondary amino and octadecyl silane in acetone. The QuEChERS extraction conditions were optimized, and the matrix effects that might influence recoveries were evaluated and minimized using matrix‐matched calibration curves. Under the optimized conditions, the calibration curves for 29 pesticides showed good linearity in the concentration range of 0.1–10 μg/mL with determination coefficient R² > 0.998. The limits of quantification of the 29 pesticides were 0.006–0.06 mg/kg for green pepper, 0.005–0.039 mg/kg for red pepper and 0.014–0.25 mg/kg for dehydrated red pepper. These values are below the suggested regulatory maximum residue limits. The mean recoveries ranged between 70.1 and 110%, and the relative standard deviations were <13%. The developed method was successfully applied to commercial samples. Some samples were found to contain the 29 pesticides with levels below the legal limits. Copyright © 2016 John Wiley & Sons, Ltd.