Determination of acrylamide in starch-based foods by HPLC with pre-column ultraviolet derivatization

A new method is developed for the determination of acrylamide in starch-based foods. The method included the extraction of acrylamide with water, defatting with hexane, derivatization with potassium bromate (KBrO(3)) and potassium bromide (KBr), liquid-liquid extraction with ethyl acetate-hexane (4:1), and concentration. The final analyte (2-bromopropenamide, 2-BPA) is analyzed by high-performance liquid chromatography coupled with diode array detection for quantification and by gas chromatography coupled to mass spectrometry for confirmation. The chromatographic analysis is performed on an ODS-3 C(18) column, and good retention and peak response of acrylamide are achieved under the optimal conditions. The limit of detection and quantitation are estimated to be 15 and 50 μg/kg, respectively. The recoveries of acrylamide from the commercial samples are spiked at levels of 50-1000 μg/kg, and range between 89.6 and 102.0%. These results show that this method should be regarded as a new, low-cost, and robust alternative for conventional investigation of acrylamide.     

柱前衍生化-气相色谱-质谱法定量测定食品中丙烯酰胺的含量

建立了气相色谱-质谱(GC-MS)定量测定食品中丙烯酰胺含量的分析方法。选择13C3-丙烯酰胺作为内标物。通过超纯水提取食品中的丙烯酰胺,经正己烷脱脂两次后,在酸性条件下选用溴化钾/溴酸钾为衍生剂进行衍生化反应,再采用乙酸乙酯进行液-液萃取两次,最后用三乙胺将丙烯酰胺转化为更稳定的产物2-溴丙烯酰胺,利用质谱检测器在选择离子扫描模式下测定2-溴丙烯酰胺。该方法在0.05～2.00 mg/kg范围具有良好的线性(r2=0.9995);检出限和定量限分别达到3 μg/kg和7 μg/kg;回收率范围为62.7%～65.5%。通过与前期建立的液相色谱-串联质谱(HPLC-MS/MS)方法进行对比,该法在薯片和面包样品中丙烯酰胺的检测结果略偏高,是一种可以用于常见食品中丙烯酰胺含量测定的分析方法。     

液相色谱-电喷雾质谱/质谱法测定高温烹制的淀粉类食品中的丙烯酰胺

以C18反相色谱柱为分析柱,以0.1%甲酸水溶液-甲醇(体积比为98∶2)为流动相,采用同位素稀释液相色谱-电喷雾 质谱/质谱(LC-MS/MS)技术对加热淀粉类食品中的丙烯酰胺进行了测定。利用Oasis HLB固相萃取柱对样品进行净化。方 法的线性范围为10～500 μg/L,线性相关系数为0.9995。方法的定性检出限为6 μg/kg,定量检出限为20 μg/kg。高 、中、低3个浓度水平的加标回收率为96.8%~97.4%,相对标准偏差小于10%。     

Development of a quantitative method for determination of acrylamide in infant powdered milk and baby foods in jars using isotope dilution liquid chromatography/electrospray ionization tandem mass spectrometry

An improved method has been developed for the determination of acrylamide in infant powdered milk and baby foods in jars, a particular class of foodstuffs which represent an important source of nutrition for young infants and babies. This method uses isotope dilution liquid chromatography coupled to a tandem mass spectrometer with electrospray ionization and is significantly more sensitive than previous published methods with a limit of quantification estimated at 1 microg kg(-1). The new method offers effective sample preparation procedures including defatting with petroleum ether, extraction with aqueous solution of sodium chloride, further liquid-liquid extraction with ethyl acetate and clean-up by solid-phase extraction (SPE) with HLB 200 mg cartridges. The analytical method was well validated and good results were obtained with respect to repeatability (RSD < 5%) and recovery (86-97%) which fulfilled the requirements defined by European Union (EU) legislation. The acrylamide level in infant powdered milk and baby foods in jars were 3.01-9.06 microg kg(-1) and 6.80-124.93 microg kg(-1), respectively. Especially, this new method is successfully applied to the trace quantification of acrylamide in infant/baby foods, the content of which is less than 10 microg kg(-1).     

Soxhlet extraction of acrylamide from potato chips

The problem of complete extraction of acrylamide from potato chips was investigated. A method was developed based on the Soxhlet extraction technique. A defatted sample was extracted continuously with methanol, for 10 days, in a Soxhlet extractor. After about 7 days, a constant concentration of acrylamide was reached. This indicates that all the acrylamide that could be removed from the sample had been extracted. Acrylamide was identified in the extract using GC-MS and scan mode. Total concentration was 14500 microg kg(-1) using GC-FID and standard additions. Complementary determinations, using an external standard (GC-FID and GC-MS) and an internal standard (GC-FID), showed results within +/- 5%. A previously published study, using a static extraction method and GC-MS and LC-MS-MS, showed concentrations of 2287 and 1993 microg kg(-1), respectively. The results are discussed in relation to a recent model and analogous experiments. The extracted amount of acrylamide is affected by several parameters: solvent properties, solvent volume, extraction time, temperature, particle size, and the microstructure of the sample.     

气相色谱-质谱法测定油炸淀粉类食品中的丙烯酰胺

 建立了油炸淀粉类食品中丙烯酰胺的溴衍生化气相色谱-质谱(GC-MS)测定方法。样品经水提取、高速离心、石墨化 炭黑柱净化、溴衍生化后,以GC-MS选择离子进行定性,同位素稀释技术定量。该方法的检出限为5 μg/kg,回收率为90％ ～105％,相对标准偏差为6.3％。利用该方法对市场上某些油炸淀粉类食品进行了初步测定,发现薯片和炸薯条中含有27 8~4518 μg/kg的丙烯酰胺。     

Development and single-laboratory validation of a reversed-phase liquid chromatography-electrospray-tandem mass spectrometry method for identification and determination of acrylamide in foods

A rapid and accurate method using reversed-phase liquid chromatography-tandem mass spectrometry interfaced with electrospray was developed for determination of acrylamide in cooked food samples. A simplified sample treatment procedure using an extraction step with acidified water without cleanup was developed. A C18 column with an aqueous formic acid-methanol mixture as the mobile phase was used under isocratic conditions. The method was validated in-house for robustness, limits of detection (LOD) and quantitation (LOQ), linearity, recovery, and accuracy both on standard and baked-product and potato flour matrixes. Good results in the low ppb level were obtained for LOD (< 15 microg/kg) and LOQ (< 25 microg/kg) of acrylamide in samples. Excellent linearity (r2 = 0.999-1.000) was established over 2 orders of magnitude by performing statistical tests. The absence of both constant and proportional systematic errors demonstrated good method accuracy. Excellent results were obtained for intraday repeatability (RSD < 1.5%) and between-day precision (RSD < 5%). Extraction recoveries from food products were calculated in the 97 +/- 3-99 +/- 2% (n = 6) range with a labeled internal standard (13C3-acrylamide). The applicability of the method to determination of acrylamide in cooked food products was demonstrated.     

超高效液相色谱-大气压化学电离-串联质谱法测定烘焙咖啡中丙烯酰胺

建立了烘焙咖啡中丙烯酰胺的超高效液相色谱-大气压化学电离-串联质谱（UHPLC-APCI-MS/MS）分析方法。样品经甲醇提取，HLB固相萃取（SPE）小柱净化，Brownlee validated AQ C18色谱柱分离，采用大气压化学电离（APCI）源，正离子扫描和多反应监测（MRM）模式对丙烯酰胺进行检测，内标法定量。结果表明，丙烯酰胺在0.5~100.0 μg/L范围内具有良好的线性关系，相关系数（r²）为0.999，方法检出限为5.0 μg/kg，定量限为10.0 μg/kg。在100.0、200.0和1000.0 μg/kg添加水平下，丙烯酰胺的回收率为94.6%~115.0%，相对标准偏差（RSD）值为2.8%~3.6%（n=6）。本方法采用APCI源作为离子化方式，能有效地减少咖啡基质对丙烯酰胺的基质干扰，前处理简单，灵敏度高，适用于咖啡中丙烯酰胺的日常检测。     

Solid-phase extraction and cleanup procedures for determination of acrylamide in fried potato products by liquid chromatography/mass spectrometry

In response to recent discoveries of acrylamide in heated foods, a solid-phase extraction and cleanup protocol was developed for the determination of acrylamide in fried or baked potato samples by liquid chromatography/mass spectrometry (LC/MS). The analyte was extracted from the matrix by using 2M NaCl, and an aliquot of the initial extract was loaded onto a reversed-phase cartridge. After the analyte was eluted from the cartridge, the eluate was cleaned up on a mixed-mode cation-exchange cartridge. The eluate was then evaporated, and the residue was reconstituted in mobile phase before LC/MS analysis. Recoveries, based on the recovery of an added internal standard, ranged from 96 to 101% with relative standard deviations (RSDs) of 5-11%. The response was linear for a concentration range of 100-2000 ng/g with a coefficient of determination (R2) of 0.992 (n = 25). An interday study showed good accuracy and precision of the method over a 3-day period with a recovery of 98% and an RSD of 9.5% (n = 15). The analyses of 6 potato chip samples showed concentrations of incurred acrylamide ranging from 260 to 1500 ng/g.     

An improved method validation for rapid determination of acrylamide in foods by ultra-performance liquid chromatography combined with tandem mass spectrometry

An improved method was validated for the determination of acrylamide in foods using ultra-performance liquid chromatography (UPLC) coupled to eletrospray ionization tandem mass spectrometry (MS/MS) in the present study. This improved method supplies a rapid quantitative procedure of acrylamide with a run time of only 3 min. Results showed a good repeatability (RSD< or =4.5%) with 50, 100, 250, 500 and 1000 microg/kg spiked concentrations in potato crisps in within-day (n=5) and day-to-day (n=10) precision tests. Meanwhile, good recoveries (81.6-99.0%) were obtained with the same spiked concentrations in acrylamide-free cereal samples (n=3). The excellent method validation data and proficiency test results (Z-score: -0.1) of the official Food Analysis Performance Assessment Scheme (FAPAS) suggested that the present quantitative method could be applied for rapid determination of acrylamide in many investigations.     

Determination of PAH in food samples by HPLC with fluorimetric detection following sonication extraction without sample clean-up

A rapid method is proposed for the determination of 16 polycyclic aromatic hydrocarbons (PAH) in non-fatty food (mashed potato, potato and toasted bread samples) based on their extraction with ethyl ether-methylene chloride (1:1) by sonication, and subsequent separation by high-performance liquid chromatography (HPLC) with fluorimetric detection. A Hypersil Green PAH column was used with a gradient of acetonitrile-water as the mobile phase, together with a programme of ten excitation and emission wavelength pairs. At levels 1.60-2320 microg kg(-1), mean recoveries of PAH were in the range 70-86% for mashed potato, potato and toasted bread samples. The relative standard deviations were in the range 4.2-11% (n = 6). Total PAH found in mashed potato were in the range 9.35-17.1 microg kg(-1), in potato samples 8.47-17.2 microg kg(-1) and in toasted bread samples 7.38-18.0 microg kg(-1), with relative standard deviations in the range 0.8-12%. Only chrysene, determined in Ortiz toasted bread (7.38 microg kg(-1)), has carcinogenic properties.     

Collaborative trial validation study of two methods, one based on high performance liquid chromatography-tandem mass spectrometry and on gas chromatography-mass spectrometry for the determination of acrylamide in bakery and potato products

A European inter-laboratory study was conducted to validate two analytical procedures for the determination of acrylamide in bakery ware (crispbreads, biscuits) and potato products (chips), within a concentration range from about 20 microg/kg to about 9000 microgg/kg. The methods are based on gas chromatography-mass spectrometry (GC-MS) of the derivatised analyte and on high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) of native acrylamide. Isotope dilution with isotopically labelled acrylamide was an integral part of both methods. The study was evaluated according to internationally accepted guidelines. The performance of the HPLC-MS/MS method was found to be superior to that of the GC-MS method and to be fit-for-the-purpose.     

Determination of residues of enrofloxacin and its metabolite ciprofloxacin in chicken muscle by capillary electrophoresis using laser-induced fluorescence detection

A method for the residue analysis of the veterinary antimicrobial agent enrofloxacin and its active desethyl metabolite ciprofloxacin in chicken muscle tissue has been developed and validated. The detection of the analytes was performed by laser-induced fluorescence (LIF) detection using a HeCd laser (lambda(ex) = 325 nm) providing an enhancement in sensitivity and selectivity compared to conventional UV detection. The assay has been validated with satisfying results. The limits of quantification for enrofloxacin and ciprofloxacin were 5 microg/kg and 20 microg/kg, respectively, with a fivefold preconcentration yielded by a sample clean-up with a simple liquid-liquid extraction procedure. Calibration graphs were linear from 5 to 1000 microg/kg for enrofloxacin and from 20 to 1000 microg/kg for ciprofloxacin. The assay allows the detection of contaminated muscle samples at the required maximum residue limit of the European Union, which is 100 microg/kg for the sum of enrofloxacin and ciprofloxacin.     

气相色谱-质谱法检测食品中的丙烯酰胺

建立了一种用于食品中丙烯酰胺含量的气相色谱-质谱联用检测方法。通过水和甲醇提取食品中的丙烯酰胺,经蛋白变性净化后用溴水对其进行加成衍生化,再采用有机溶剂进行液液萃取,之后同三乙胺发生定量反应转化为性质更稳定的产物后由气相色谱-质谱联用仪检测,同位素内标法定量。该方法在0.02,0.05和0.2 mg/kg等3个添加水平下面粉和面包中丙烯酰胺的回收率处于80%和110%之间,相对标准偏差（RSD）不大于12.7%;在0.04～4.00 mg/L内呈现良好的线性关系;灵敏度高,最低检测限达到5 μg/kg;选择性好,能有效消除复杂基质带来的干扰。可作为常见样品中丙烯酰胺含量检测的确证方法。     

Analysis of acrylamide in cooked foods by liquid chromatography tandem mass spectrometry

A method using liquid chromatography tandem mass spectrometry (LC-MS-MS) with electrospray for the analysis of acrylamide in foods is reported. The method comprises the addition of deuterium-labelled acrylamide-d3, extraction with water, mixed mode solid phase extraction, ultrafiltration and a graphitised carbon column for chromatography. The transitions m/z 72 > 55, 72 > 54, 72 > 44, 72 > 27, 72 > 72 and 75 > 58 were recorded in multiple reaction monitoring mode for identification and quantification. In-house validation data for products from potatoes and cereals (30 to 10,000 microg kg(-1)) are presented (accuracy 91 to 102%, relative standard deviation 3 to 21%). Interlaboratory validation data (comparison with gas chromatography mass spectrometry, 25 to 2000 microg kg(-1)) showed excellent results (r2 = 0.998).     

固相萃取-气相色谱串固相萃取-气相色谱-串联质谱法测定水果中11种三唑类杀菌剂

建立了固相萃取-气相色谱-串联质谱同时测定水果中11种三唑类杀菌剂残留的方法。采用乙腈匀浆提取样品中的待测组分,经固相萃取法(SPE)净化,采用气相色谱-串联质谱在多反应监测(MRM)模式下进行测定,外标法定量。分别对水果样品进行4个水平(10、50、100、250 μg/kg)的加标回收试验,回收率为82.6%～117.1%,相对标准偏差小于10%,定量限(LOQ,以信噪比(S/N)为10计)为0.8～3.4 μg/kg。结果显示该方法的背景干扰低,灵敏度高,定量限低于国家标准及有关文献报道值,适合橘子等水果中三唑类杀菌剂的同时测定。     

Simultaneous Analysis of Herbicide Metribuzin and Quizalofop-p-ethyl Residues in Potato and Soil by GC-ECD

A robust and sensitive method was developed for the simultaneous analysis of metribuzin and quizalofop-p-ethyl residues in potato and soil, based on solid-phase extraction (SPE) coupled to capillary gas chromatography with electron capture detector (GC-ECD). Residues of two herbicides were extracted from potato and soil with acetone and methanol–water, followed by SPE to remove coextractives, before analysis by GC-ECD. SPE procedures were performed on Florisil cartridges (500 mg, 3 mL), the analytes from potato and soil matrix were eluted with petroleum ether-acetic ether (9:1 v/v, 5 mL) and petroleum ether-acetic ether (8:2 v/v, 2 mL), respectively. Limits of quantification of the method were 0.01 mg kg^?1, and the mean recoveries ranged from 72.9 to 109.5% with relative standard deviation ranging from 0.7 to 9.2% at the three spike levels (0.01, 0.1, and 0.5 mg kg^?1). The proposed method was successfully applied to the analysis of metribuzin and quizalofop-p-ethyl residues in potato and soil samples from an experimental field. Direct confirmation of the analytes in real samples was achieved by gas chromatography-mass spectrometry (GC–MS).     

Dynamic hollow fiber protected liquid phase microextraction and quantification using gas chromatography combined with electron capture detection of organochlorine pesticides in green tea leaves and ready-to-drink tea

The dynamic hollow fiber protected liquid phase microextraction (DHFP-LPME) technique was evaluated for the extraction of organochlorine pesticides (OCPs) in green tea leaves and ready-to-drink tea prior to gas chromatography combined-electron capture detection (GC-ECD) analysis. A conventional microsyringe with a 1.5 cm length of hollow fiber attached to its needle was connected to a syringe pump to perform the extraction. The microsyringe was used as both the microextraction device and the sample introduction device for GC-ECD analysis. In this work, the organochlorine pesticides were extracted and condensed to a volume of 3 microl of organic extracting solvent (1-octanol) confined within a 1.5 cm length of hollow fiber. The effects of extraction solvent, extraction time, sample agitation, plunger speed, and extraction temperature and salt concentration content on the extraction performance were also investigated. Good enrichments were achieved (34-297-fold) with this method, and good repeatabilities of extraction were obtained, with full name (RSDs) below 12.57%. Detection limits were much below 1 microg l(-1) for ready-to-drink tea and much below 1 microg g(-1) for green tea leaves.     

Use of solid-phase microextraction/gas chromatography-electron capture detection for the determination of energetic chemicals in marine samples

Gas chromatography with electron capture detection (GC-ECD) is a highly explosive-sensitive analytical technique. However, its application to the analysis of sediment extracts is hampered by the presence of numerous endogenous interferences. In the present study, solid-phase microextraction (SPME) was used both as a purification technique for sediment extracts and as an extraction technique for water samples prior to analysis by GC-ECD. SPME/GC-ECD coupling was optimized and applied to the trace analysis of nine explosives including nitroaromatics and RDX in real seawater and marine sediment samples. Addition of a high concentration of salt (30%, w/v) in the aqueous medium and use of a carbowax/divinylbenzene (CW/DVB) coating led to optimal extraction efficiencies. Method detection limits (MDLs) ranged from 0.05 to 0.81 microg/L in water and from 1 to 9 microg/kg in dry sediment. Except for RDX, spike recoveries in seawater were satisfactory (89-147%) when samples were fortified at 2 microg/L of each analyte. Spike recoveries from dry sediment fortified at 10 microg/kg of each analyte gave lower recoveries but these could also be due to degradation in the matrix. With a smaller volume of aqueous sample required compared to solid-phase extraction (SPE), SPME is an attractive method for the analysis of limited volumes of sediment pore-water. Moreover, the use of SPME eliminated interferences present in sediment extracts thus allowing the detection of the target analytes that were otherwise difficult to detect by direct injection.     

Validation of a novel derivatization method for GC–ECD determination of acrylamide in food

This paper proposes a new method for quantitative analysis of acrylamide in cereal-based foods and potato chips. The method uses reaction with trifluoroacetic anhydride, and analyses the resulting derivative by use of gas chromatography with electron-capture detection (GC–ECD). The effects of derivatization conditions, including temperature, reaction time, and catalyst, on the acylation reaction were evaluated. Chromatographic analysis was performed on an SE-54 capillary column. Under the optimum conditions, good retention and peak response were achieved for the acrylamide derivative. The analytical method was fully validated by assessment of LODs and LOQs (1 ng g^?1 and 25 ng g^?1, with relative standard deviations (RSD) 2.1 and 3.6, respectively), linearity (R?=?0.9935 over the range 0.03–10 μg g^?1), and extraction recovery (>96 %, with RSD below 2.0, for acrylamide spiked at 1, 20, 50, and 100 ng g^?1; 99.8 % for acrylamide content >1000 ng g^?1). The method requires no clean-up of the acrylamide derivative before injection. The method has been successfully used to determine acrylamide levels in different commercial cereal-based foods, French fries, and potato chips.