[Identification method of 2-methylisoborneol and geosmin in water by purge and trap-gas chromatography-mass spectrometry].

OBJECTIVE: To establishe an analysis and identification method for 2-methylisoborneol(2-MIB) and geosmin(GSM) in water using purge and trap-gas chromatography-mass spectrometry. METHODS: The samples were enriched and analyzed using a purge and trap system, followed by the separation on a DB-624(30 m×0.25 mm, 1.4 µm) chromatographic column. Quantification was performed using gas chromatography-mass spectrometry with the selected ion monitoring and internal standard calibration. RESULTS: The calibration curves for 2-MIB and GSM showed an excellent linearity in the range of 1 to 100 ng/L with R~2 values greater than 0.999. The detection limit and quantification limit for both 2-MIB and GSM were 0.33 ng/L and 1.0 ng/L, respectively. Spike recovery experiments were further carried on the source water and drinking water at three concentration levels. It showed that the average recoveries were from 82.0% to 111.0% for 2-MIB while 84.0% to 110% for GSM. Additionally, the test precision of 2-MIB and GSM ranged from 1.9% to 7.3% and 1.9% to 5.0%(n=6), respectively. The analysis of multiple samples including the local source water, treated water and distribution network water confirmed the existence of 2-MIB and GSM. CONCLUSION: Compared to the national standard(GB/T 5750.8-2023), the proposed method enables fully automated sample introduction and analysis without the extra pre-treatment. It provides the advantages of simplicity, good repeatability and high accuracy.

An Occurrence and Exposure Assessment of Paralytic Shellfish Toxins from Shellfish in Zhejiang Province, China.

The intake of paralytic shellfish toxins (PSTs) may adversely affect human health. Therefore, this study aimed to show the prevalence of PSTs from commercially available shellfish in Zhejiang Province, China, during the period of frequent red tides, investigate the factors affecting the distribution of PSTs, and assess the risk of PST intake following the consumption of bivalve shellfish among the Zhejiang population. A total of 546 shellfish samples were collected, 7.0% of which had detectable PSTs at concentrations below the regulatory limit. Temporal, spatial, and interspecific variations in the occurrence of PSTs were observed in some cases. The dietary exposure to PSTs among the general population of consumers only was low. However, young children in the extreme scenario (the 95th percentile of daily shellfish consumption combined with the maximum PST concentration), defined as 89-194% of the recommended acute reference doses, were possibly at risk of exposure. Notably, Arcidae and mussels were the major sources of exposure to toxins. From the public health perspective, PSTs from commercially available shellfish do not pose a serious health risk; however, more attention should be paid to acute health risks, especially for young children, during periods of frequent red tides.

[Occurrence and exposure assessment of fumonisins from grains and grain products in Zhejiang Province in 2018-2019].

OBJECTIVE: To monitor fumonisins(FBs) in grains and grain products in Zhejiang and assess the exposure risks of FBs to local residents. METHODS: Liquid chromatography coupled with tandem mass spectrometry method was used to determine the occurrence of FBs in rice, millet, dried noodles, instant noodles, and maize grains, and food frequency questionnaires were used to collect the food consumption data of Zhejiang population. Then, the simple probability distribution model was used to assess the exposure risk. RESULTS: The levels of FBs in rice, millet, dried noodles and instant noodles were relatively low. The occurrence of FB_1, FB_2 and FB_3 in these foods was 0-23.7%, 0-16.7% and 0-5.4%, respectively, and the mean levels were not detected(ND)-22.36, ND-20.63 and ND-7.19 µg/kg correspondingly. However, the levels of FBs in maize grains were relatively high. The occurrence of FB_1, FB_2, and FB_3 in maize grains was 100%, 93.6% and 90.3%, respectively, and the mean levels were 638.99, 103.54 and 59.69 µg/kg correspondingly. In 12.9% of the maize grain samples, the levels of FBs were higher than the standard reference. The residents were at low exposure risk overall. The mean estimated daily intake(EDI) of FBs was far lower than the provisional maximum tolerable daily intake of 2 µg/(kg·BW·d). However, 0.30% of the residents were at high risk. Among people of different ages, the mean EDI of children, adults, and elderly were 0.43, 0.28 and 0.29 µg/(kg·BW·d) respectively, and children were in the highest exposure levels of FBs. Among the tested five foodstuffs, rice and maize grains were the main sources of FBs exposure. CONCLUSION: Except for maize grains, the levels of FBs in grains and grain products were relatively low, and Zhejiang residents were at low FBs exposure risk generally.

Simultaneous Determination of 12 Preservatives in Pastries Using Gas Chromatography-Mass Spectrometry.

(1) Background: Preservatives may pose a potential threat to human health. To ensure food safety, this study has devised a method that concurrently detects a dozen preservatives (acetic acid, propionic acid, dehydroacetic acid, benzoic acid, sorbic acid, dimethyl fumarate, methyl parahydroxybenzoate, ethyl parahydroxybenzoate, propyl parahydroxybenzoate, isopropyl parahydroxybenzoate, butyl parahydroxybenzoate, and isobutyl parahydroxybenzoate) in pastry, utilizing gas chromatography-mass spectrometry. (2) Methods: The pastry samples were acidified with hydrochloric acid, extracted with acetonitrile via vortexing, purified by hexane and saturated with sodium chloride solution to remove lipids and impurities, and then concentrated via nitrogen blowing. The method was then quantitatively analyzed using GC-MS with the internal standard method after methanol re-dissolution. (3) Results: The results showed that the content of the 12 preservatives had good linearity within the range of 1.0-50 µg/mL, with correlation coefficients all greater than 0.99. The method detection limit was 0.04-2.00 mg/kg and the quantification limit was 0.12-6.67 mg/kg. The average recovery rates of the samples at three different spiked concentrations of low, medium, and high were 70.18-109.22%, and the relative standard deviations were 1.82-9.79% (n = 6). (4) Conclusions: This method requires a small amount of sample, has high sensitivity, and is simple and fast to operate, making it suitable for the simultaneous determination of 12 preservatives in pastry. This approach contributes to the effective surveillance and regulation of preservative usage in pastries, thereby safeguarding public well-being.

Optimization of Physical Refining Process of Camellia Oil for Reduction of 3-Monochloropropane-1,2-Diol (3-MCPD) Ester Formation Using Response Surface Methodology on a Laboratory Scale.

Refined and deodorized camellia oil has been reported to contain a high amount of 3-monochloropropane-1,2-diol esters (3-MCPDE) due to the high-temperature deodorization step. To reduce 3-MCPDE in camellia oil, the physical refining process of camellia oil was simulated on a laboratory scale. Response surface methodology (RSM) was designed to modify and optimize the refining process with five processing parameters (water degumming dosage, degumming temperature, activated clay dosage, deodorization temperature and deodorization time). The optimized new refining approach achieved a 76.9% reduction in 3-MCPDE contents, in which the degumming moisture was 2.97%, the degumming temperature was 50.5 °C, the activated clay dosage was 2.69%, the deodorizing temperature was 230 °C, and the deodorizing time was 90 min. A significance test and analysis of variance results demonstrated that the deodorization temperature and deodorization time contributed significantly to the reduction of 3-MCPD ester. The joint interaction effects of activated clay dosage and deodorization temperature were significant for 3-MCPD ester formation.

Determination of ß2-Agonist Residues in Fermented Ham Using UHPLC-MS/MS after Enzymatic Digestion and Sulfonic Resin Solid Phase Purification.

ß2-agonists are a class of synthetic sympathomimetic drugs with acute poisoning effects if consumed as residues in foods. To improve the efficiency of sample preparation and to overcome matrix-dependent signal suppression in the quantitative analysis of four ß2-agonists (clenbuterol, ractopamine, salbutamol, and terbutaline) residues in fermented ham, an enzyme digestion coupled cation exchange purification method for sample preparation was established using ultra-high performance liquid chromatography and tandem mass spectrometry (UHPLC-MS/MS). Enzymatic digests were subject to cleanup treatment on three different solid phase extraction (SPE) columns and a polymer-based strong cation resin (SCR) cartridge containing sulfonic resin was found to be optimal compared with silica-based sulfonic acid and polymer sulfonic acid resins based SPEs. The analytes were investigated over the linear range of 0.5 to 10.0 µg/kg with recovery rates of 76.0-102.0%, and a relative standard deviation of 1.8-13.3% (n = 6). The limit of detection (LOD) and the limit of quantification (LOQ) were 0.1 µg/kg and 0.3 µg/kg, respectively. This newly developed method was applied to the detection of ß2-agonist residues in 50 commercial ham products and only one sample was found to contain ß2-agonist residues (clenbuterol at 15.2 µg/kg).

Levels and Health Risk Assessment of Polycyclic Aromatic Hydrocarbons in Vegetable Oils and Frying Oils by Using the Margin of Exposure (MOE) and the Incremental Lifetime Cancer Risk (ILCR) Approach in China.

A total of 139 vegetable oils and 48 frying oils produced in China were tested for the levels of 15 Environmental Protection Agency-regulated polycyclic aromatic hydrocarbons (PAHs). The analysis was completed by high-performance liquid chromatography-fluorescence detection (HPLC-FLD). The limit of detection and limit of quantitation were ranged between 0.2-0.3 and 0.6-1 µg/kg, respectively. The average recovery was 58.6-90.6%. The highest mean of total PAHs was found in peanut oil (3.31 µg/kg), while the lowest content was found in olive oil (0.39 µg/kg). In brief, 32.4% of vegetable oils exceeded the European Union maximum levels in China. The detected level of total PAHs in vegetable oils was lower than the frying oils. The mean dietary exposure to PAH15 ranged from 0.197 to 2.051 ng BaPeq/kg bw/day. The margin of exposure values was greater than 10,000, and the cumulative probabilities of the incremental lifetime cancer risk of different age groups were less than the priority risk level (10-4). Therefore, there was no potential health concern for specific populations.

Occurrence of Furfural and Its Derivatives in Coffee Products in China and Estimation of Dietary Intake.

This is the first report on the content of furfural and its derivatives in coffee products in China. The concentrations of furfural and its derivatives in 449 sampled, commercially available coffee products in China were analyzed through a GC-MS technique, and the associated health risks were estimated. As a result, 5-hydroxymethyl furfural (5-HMF) was identified as the predominant derivative compound, with the highest concentration of 6035.0 mg/kg and detection frequency of 98.7%. The mean dietary exposures of 5-HMF, 5-MF(5-methylfurfural), and 2-F(2-furfural) in coffee products among Chinese consumers were 55.65, 3.00, and 3.23 µg/kg bw/day, respectively. The ranges of mean dietary intake of furfural and its derivatives based on age groups were all lower than the acceptable daily intake (ADI) and the toxicological concern threshold (TTC). Risk evaluation results indicate that coffee product intake did not pose potential risks to consumers. Notably, the analysis revealed that children aged 3-6 years had the highest mean exposure due to their low body weight.

Risk assessment of 3-monochloropropane-1,2-diol esters through dietary exposure from edible oils for the Zhejiang population in China by Monte Carlo simulation.

The purpose of this study was to assess the risk of 3-monochoropropane-1,2-diol (3-MCPD) esters from edible oils for the Zhejiang population in China. Exposure assessment of 3-MCPD esters was evaluated by Monte Carlo simulation based on the concentrations of 3-MCPD esters in edible oils combined with survey data on the eating habits of Chinese residents classified by age group and gender. The simulation results indicated that the mean daily intakes (CDI) of 3-MCPD esters for children 7-10 years old were 2.154 µg (kg BW d)-1 for boys and 2.049 µg (kg BW d)-1 for girls, which are lower than the provisional maximum tolerable daily intake (PMTDI) of 4 µg (kg BW d)-1 for 3-MCPD and 3-MCPD esters individually or in combination, set by the Joint FAO/WHO Expert Committee on Food Additives. The range of mean dietary intakes of 3-MCPD esters in different subpopulation groups ranged 1.242-1.672 µg (kg BW d)-1, which was lower than the PMTDI. However, the CDI values of 3-MCPD esters in high percentile exposure subgroups (95th, 99th) of males (7-49 years old) and females (7-10 and 50-75 years old) were all above 4µg (kg bw d)-1. Outside of the senior group (50-75 years old), males had more exposure to 3-MCPD than females. The average hazard indexes (HI) of 3-MCPD esters to male and female children were 1.257 and 1.024, respectively, indicating there was a risk, but no immediate measures are required to address this risk. The average HI of 3-MCPD esters to adolescent, adult, and seniors were all below 1, indicating risk for those age groups were at an acceptable level.

Simultaneous determination of the residues of anesthetics and sedatives in fish using LC-QLIT-MS/MS combined with DSPE.

Liquid chromatography coupled with quadrupole linear ion trap tandem mass spectrometry (LC-QLIT-MS/MS) technology operated in electrospray ionization (ESI) was developed for tracing anesthetic (AETs) and sedatives (SDTs) in fish. Sampling procedure was achieved by using acetonitrile extraction followed by dispersive solid phase extraction (DSPE) clean-up. Under the optimized laboratory conditions, reliable qualitative confirmation was obtained through the multiple reaction monitoring-information dependent acquisition-enhanced product ion (MRM-IDA-EPI) mode. Results indicated a favorable linear in the concentration range of 1-100 µg∙kg-1 (0.1-10 µg∙kg-1 for MS-222), with regression coefficient not less than 0.9997. The detection limit ranges from 0.03 to 0.4 µg∙kg-1 (S/N = 3). The validated method was applied to determine AETs and SDTs in fish with satidfied recoveries of 86.3 %-111.7 % and the relative standard deviations (RSD) of 1.9 %-8.9 % (n = 6). Practical samples analysis indicated that the proposed method is simple, rapid, sensitive and accurate for identification of AETs and SDTs.

Optimization of pretreatment methods for N-nitrosamine compounds in ready-to-eat aquatic products / 预防医学

Objective@#To optimize the pretreatment method of N-nitrosamine compounds in ready-to-eat aquatic products. @*Methods@#Market-sold ready-to-eat aquatic products were collected, homogenized and distilled by steam. The samples were extracted for 10 minutes using dispersive liquid-liquid microextraction (DLLME) with ethanol, trichloromethane and sodium chloride (3.0 g). After centrifugation, the organic phase in the lower layer was collected and subjected to gas chromatography-tandem mass spectrometry (GC-MS/MS). The six common N-nitrosamine compounds were determined in ready-to-eat aquatic products using multiple reaction monitoring mode (MRM) and quantified by the internal standard method. @*Results@#The optimized method exhibited a good linear relationship at concentrations of 10.0 to 500 μg/L for determination of 6 N-nitrosamine compounds (correlation coefficient of greater than 0.999), with 0.05 to 0.60 μg/kg limit of detection, 0.15 to 1.60 μg/kg limit of quantitation, mean spiked recovery rates of 71.8% to 108.9%, and relative standard deviations of 1.4% to 8.6%. N-Nitrosodimethylamine showed the highest detection rate in 20 market-sold ready-to-eat aquatic products (90%), and the detection rates of N-Nitrosopyrrolidine, N-Nitrosodiethylamine and N-dibutylnitrosamine were 15%, 10% and 10%, respectively. @*Conclusion@#Steam distillation combined with DLLME may optimize the pretreatment method of N-nitrosamine compounds in ready-to-eat aquatic products and meet the measurement requirements.

Occurrence and Exposure Assessment of Deoxynivalenol and Its Acetylated Derivatives from Grains and Grain Products in Zhejiang Province, China (2017-2020).

Deoxynivalenol (DON) together with its acetylated derivatives cause detrimental effects on human health, and the purpose of this study was to assess the prevalence of DON and its acetylated derivatives from grains and grain products in Zhejiang province, China, and to assess the risk of DON and its acetylated derivatives due to multiple consumptions of grains and grain products among the Zhejiang population. Food samples numbering 713 were collected, and the LC-MS/MS method was used to determine the toxins. The levels of toxins from grains and grain products were relatively low: DON was the toxin at the highest levels. The food frequency questionnaire was used to collect food consumption data. The result of exposure assessments showed that the population was overall at low levels of toxin exposure. The probable mean group daily intake of toxins was 0.21 µg/kg bw/day, which was far from the group provisional maximum tolerable daily intake of 1 µg/kg bw/day, but 0.71% of participants were at high exposure levels. Rice and dried noodles (wheat-based food) were the main sources of toxin exposure, and reducing the consumption of rice and dried noodles while consuming more of other foods with lower levels of toxins is recommended.

A novel single step solid-phase extraction combined with bromine derivatization method for rapid determination of acrylamide in coffee and its products by stable isotope dilution ultra-performance liquid chromatography tandem triple quadrupole electrospray ionization mass spectrometry.

This work aimed to establish a novel determination method for acrylamide in coffee and its products by ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). Acrylamide in samples were prepared by a single-step solid-phase extraction clean-up using mixed mode sorbents. The bromine derivatization efficiency of acrylamide and its internal standard were improved at an acidic condition. After derivation, the retention capability of acrylamide and its resistance to interference were significantly improved. The limit of detection (LOD) and the limit of quantification (LOQ) were 1.2 and 4 µg/kg for roasted and instant coffees, while they were 0.24 and 0.8 µg/kg for ready-to-drink coffees. The average recoveries for acrylamide ranged from 99.3 to 102.2% in coffee and its products. All the results showed that the developed method was simple, quick, specific and suitable for screening and determination of acrylamide in batch samples of coffee and its products.

Analysis of furan and its major furan derivatives in coffee products on the Chinese market using HS-GC-MS and the estimated exposure of the Chinese population.

The current study analysed concentrations of furan and its derivatives in coffee products commercially available in China based on an improved headspace gas chromatography-mass spectrometry (HS-GC-MS) method and estimated health risks. A total of 101 samples of coffee products on the Chinese market was analysed. Furan (98%, ND-6569 µg/kg) and 2-methylfuran (100%, 2-29639 µg/kg) were the compounds with the highest concentrations and detection rates in coffee products. The mean dietary exposure of Chinese consumers to furan and the sum of furan, 2-methylfuran and 3-methylfuran in coffee products was 0.09 and 0.46 µg/kg bw/day, respectively. For the neoplastic effects of furan, the margin of exposure (MOE) was 14,556 for the mean dietary exposure of consumers. For the non-neoplastic effects of furan, MOEs were 711 and 139 for furan and the sum of furan, 2-methylfuran and 3-methylfuran, respectively. Overall, a health concern is indicated for coffee consumers with MOEs below 10000.

Determination of Polycyclic Aromatic Hydrocarbons in Traditional Chinese Medicine Raw Material, Extracts, and Health Food Products.

The four polycyclic aromatic hydrocarbon markers (PAH4) of benzo[a]anthracene (BaA), chrysene (Chr), benzo[b]fluoranthene (BbF), and benzo[a]pyrene (BaP) are indicators showing polycyclic aromatic hydrocarbon (PAH) contamination levels in Chinese medicine raw materials (CMRMs), extracts and health food products; Samples of herbal medicine, herbal extracts, and food supplements were extracted with n-hexane, then cleaned up sequentially on Florisil and EUPAH solid-phase extraction (SPE) columns. A gas chromatography-mass spectrometry method for the determination of four polycyclic aromatic hydrocarbon markers in Chinese medicine raw material, extracts, and health food products was established; In spiked-recovery experiments, the average recovery was about 78.6-107.6% with a precision of 2.3-10.5%. The limit of quantification (LOQ) and limit of detection (LOD) of the PAH4 markers in this method were 2.0 µg/kg and 0.7 µg/kg, respectively. When the developed method was utilized to determine PAH4 contents in 12 locally available health food products, 3 samples contained over 10.0 µg/kg BaP, and 5 samples contained over 50.0 µg/kg PAH4. The European Union (EU) limits for BaP and PAH4 are 10 and 50.0 µg/kg, respectively; therefore, more attention must be drawn to the exposure risk of BaP and PAH4 in CMRMs, their extracts, and health food products. According to the risk assessment based on the Margin of Exposure (MOE) method, it is recognized that the products mentioned in this study pose a low risk.

Occurrence and exposure assessment of aflatoxins in Zhejiang province, China.

The purpose of this study was to assess the risk of aflatoxins due to multiple food consumption among the Zhejiang population. Ultra-high-performance liquid chromatography coupled with tandem mass spectrometry method was used to determine aflatoxins in 792 samples. Aflatoxins were detected in 27.1% of the samples at levels between 0.07 and 262.63 µg kg-1, and aflatoxins B1 was the most frequently detected among different types of samples. 0.8% of peanut oil, 3.39% of nut products as well as 1.1% of condiments contaminated with aflatoxins B1 exceeded China national tolerance limits. Peanut oil had the highest incidence of aflatoxin, with a range from 0.17 to 22.50 µg kg-1. Using bags conferred limited advantages in reducing aflatoxin contents. Moreover, peanut and rice were the main contributors to dietary exposure to aflatoxins among Zhejiang residents. Finally, the margin of exposure values obtained by rice consumption were far from the safe margin of 10,000, indicating a potential risk to public health. The results pointed out the need for further prioritization of aflatoxins B1 risk-management actions in Zhejiang.

Determination of 15 + 1 European Priority Polycyclic Aromatic Hydrocarbons in Smoked Meat Products by Saponification/Solid-Phase Extraction and Gas Chromatography-Mass Spectrometry.

A method for the determination of 15 + 1 European priority polycyclic aromatic hydrocarbons (EUPAHs) in smoked meat samples by saponification/solid-phase extraction and gas chromatography-mass spectrometry has been developed. Both saponification and solid-phase extraction conditions were optimized, which lead to shorter sample preparation time and excellent sensitivity and selectivity. The optimal saponification condition for the lipid extract of 5.00 g smoked food sample was 5 mL KOH (1.5 mol/L)-ethanol at 70°C for 5 min, and the shorter alkaline treatment time avoided the loss of volatile EUPAHs such as Benzo[c]fluorene. All the EUPAHs showed good linearity in the range between 5.0 and 50.0 ng/mL with correlation coefficients between 0.997 and 1.00. The estimated LODs for the EUPAHs were 0.15-0.30 µg/kg, while the LOQs were 0.50-1.0 µg/kg. The three spiking levels of EUPAHs were 1.0, 2.0 and 5.0 µg/kg, and the average recovery was between 75.2 and 99.6%, while the RSD were 2.3-12.4%. This sensitive and rapid method was successfully applied to smoked meat samples from Zhejiang Province of China, and the results revealed the presence of 13 EUPAHs. Benzo[a]pyrene (BaP) was found in 19 out of 20 samples, with concentration ranging from 0.51 to 4.57 µg/kg. The sum of concentrations of PAH4 (summation of benzo(a)pyrene, chrysene, benzo(a)anthracene, and benzo(b)fluoranthene) were 2.40-53.56 µg/kg.

[Characterization and investigation of 16 European priority polycyclic aromatic hydrocarbons in commercial infant formula milk powder in Hangzhou].

OBJECTIVE: A gas chromatography-mass spectrometry(GC-MS) method for the determination of 16 European priority polycyclic aromatic hydrocarbons(16 EUPAHs) in infant formula milk powder was established, and the characterization and investigation of 16 EUPAHs in 70 milk formula powders were carried out in 2020. METHODS: After hydrolysis, extraction, saponification and solid phase extraction, infant formula milk powder was detected by GC-MS using DB-EUPAH capillary column(20 m×0.18 mm, 0.14 µm)and quantified by internal standard method. RESULTS: The average recoveries ranged from 67.8% to 116.2% and the relative standard deviations ranged from 2.0% to 15.1%(n=6). The limits of quantification and detection of the method were 0.5 and 0.2 µg/kg, respectively. The content of 16 EUPAHs was <0.2-0.48 µg/kg, including PAH4 content in the range of <0.2-0.91 µg/kg, the characterization and investigation of infant formula powder in 16 EUPAHs mainly chrysene, cyclopenta[c, d]pyrene, benz[a]anthracene, benzo[b]fluoranthene, benzo[g, h, i]perylene. CONCLUSION: The method is simple, accurate and suitable for the determination of 16 EUPAHs in infant formula milk powder. The result showed that the content of 16 EUPAHs in commercially available infant formula milk powder in Hangzhou was low and all of them met the limit requirement of European Union.

[Determination of 4 polycyclic aromatic hydrocarbons in spicy strips by vacuum concentration coupled with isotope dilution gas chromatography-mass spectrometry].

OBJECTIVE: A method based on isotope internal standard dilution was established for the determination of four polycyclic aromatic hydrocarbons(PAH4) including chrysene, benzo [a] anthracene, benzo [b] fluoranthene and benzo [a] pyrene in spicy strips sold in the markets. METHODS: The hot strips were homogenized and the target compounds were extracted with n-hexane, concentrated in vacuum, saponified and purified by solid phase extraction column, then the pretreated samples were separated by DB-EUPAH column(20 m×0. 18 mm, 0. 14 µm), detected by gas chromatography-mass spectrometry(GC-MS)and quantified by internal standard of isotope. RESULTS: The recoveries of PAH4 in different concentration levels of hot noodles were 91. 0%-103. 5%, and the relative standard deviation(RSD)was 1. 89%-6. 73%(n=6). The detection limit was 0. 30 µg/kg and the quantitative limit was 1. 0 µg/kg. The content of PAH4(sum) in 27 collected samples ranged from 1. 35 µg/kg to 11. 44 µg/kg, and the detection rate was 100%. CONCLUSION: With less solvent consumption, good purification effect and blank control, the method is simple, rapid and accurate and meets the detecting requirements of PAH4 in hot strips.