Survey of furan in heat processed foods by headspace gas chromatography/mass spectrometry and estimated adult exposure

Furan is a suspected human carcinogen that is formed in some processed foods at low ng per g levels. Recent improvements in analytical methodology and scientific instrumentation have made it possible to accurately measure the amount of furan in a wide variety of foods. Results from analysis of more than 300 processed foods are presented. Furan was found at levels ranging from non-detectable (LOD, 0.2-0.9 ng g^-1) to over 100 ng g^-1. Exposure estimates for several adult food types were calculated, with brewed coffee being the major source of furan in the adult diet (0.15 µg kg^-1 body weight day^-1). Estimates of mean exposure to furan for different subpopulations were calculated. For consumers 2 years and older, the intake is estimated to be about 0.2 µg kg^-1 body weight day^-1.     

Determination of molecular and free sulphur dioxide in foods by headspace gas chromatography

A study was made of the equilibria between SO2 in packaged liquid foods and gaseous SO2 in their headspace atmospheres as a basis for a new analytical method for the determination of molecular and free SO,. Using a gas-chromatographic method developed previously to determine SO2 at the 1 × 10⁻³ mg/l level in atmospheres saturated with water vapour, studies with aqueous solutions showed that headspace SO2 was directly proportional to molecular SOz in accordance with Henry's law.
Using the Henry's law constant for the S02/H20 system, determinations of molecular SOz were made on a white and a red wine and a fruit juice, each adjusted to five levels of pH to achieve different concentrations of molecular SO,. The results observed by the headspace method showed good agreement with those determined by a reference analytical method with white wine and fruit juice, but with red wine the reference method gave values which were more than 45% higher. Free SO2 was determined in a range of white wines by the headspace and reference methods, and the results showed high correlations.
The headspace method is rapid, precise and non-destructive. A major advantage is that, during the analysis, it does not change the complicated equilibria between SO, and its ionised species, hence complexes of SO2 and food constituents are not disturbed.     

Static headspace gas chromatography of acetaldehyde in aqueous foods and polythene terephthalate

Polythene terephthalate (PET) is frequently used as a packaging material for mineral water and other non-alcoholic beverages. PET contains detectable amounts of acetaldehyde, which is able to migrate to its packed product. An automated headspace gas Chromatographic method for the determination of acetaldehyde has been developed and was used for the quantification of acetaldehyde in aqueous food products and their PET packages. A cold trap, mounted in the GC oven, between the autosampler and analytical column was introduced as a new application. The detection limit of acetaldehyde was found to be 3 ng/ml with a standard deviation of 3%. The contents of acetaldehyde found in carbonated mineral water and lemonades ranged between 11 ng/ml and 7447 ng/ml, while the contents of acetaldehyde in the PET packages ranged from 1.1 g/g to 3.8 g/g.     

Distillation-extraction of styrene migrating from polystyrene containers to foods by gas chromatography

A simple, accurate and sensitive gas-liquid chromatographic method has been developed for the determination of styrene migrating from polystyrene containers into foodstuffs. an apparatus for the extraction of styrene was designed for the purpose, based on the BP apparatus for the determination of volatile oils. Styrene was extracted from foods by distillation with concurrent extraction from the distillate by n -hexane. Extraction was complete in 35 min. Hexane extracts were analysed by GC-FID using a glass column with durene as internal standard. Styrene levels in containers were from 1.7 to 192 μg g⁻¹ and in foods from 0.013 to 0.13 μg g⁻¹.     

Determination of acrylamide monomer in hydroponically grown tomato fruits by capillary gas chromatography—mass spectrometry

Tomato (Lycopersicon esculentum L) fruits from plants grown hydroponically on polyacrylamide gel were obtained in order to assess any possible uptake of acrylamide monomer from the nutrient solution to the fruit during cultivation. Analysis of acrylamide in the gel itself involved aqueous extraction, bromination and then capillary GC determination with nitrogen-specific detection. By standard addition a level of 0·18 ± 0·01 g kg^?1 residual monomer was found to be present in a sample of gel used by an experimental horticultural station. Tomato fruits were analysed by extraction of the aqueous phase, bromination, silica-gel cartridge clean-up and capillary GC–MS determination by selected ion monitoring. The recovery of the method was 26–62% but losses throughout were compensated for by use of 2,3-dibromo-2-dimethylpropionamide internal standard. No acrylamide monomer could be detected in tomato fruits from plants grown hydroponically on polyacrylamide gel at a limit of detection of 1 × 10^?6 g kg^?1, demonstrating that the monomer is not transferred from the growing medium into tomato fruits.     

Determination of acrylonitrile monomer in food packaging materials and in foods

An automated headspace gas chromatographic method is described using nitrogen specific detection for the quantification of acrylonitrile monomer (AN) in acrylonitrile-butadiene-styrene (ABS) food packaging tubs and in the contained foods. For a limited number of retail foods, levels of AN in ABS tubs (ranging from 2 to 10 mg/kg) and their contents (soft margarine, butter and shortening) are reported (ranging from 0.01 to 0.05 mg/kg), the results being confirmed by mass spectrometry (low and medium resolution selected ion monitoring). The latter technique was also used to quantify the levels of AN in the coatings of retail packaging films on a range of substrates, which were found to be between <0.001 and 0.02 mg/m².     

Quantitative analysis of styrene monomer in foods. A limited East Australian Survey

The levels of styrene monomer in foods packaged in polystyrene containers were determined by a headspace gas chromatography (g.c.) method and two reversed phase high-performance liquid chromatography (h.p.l.c.) methods. A total of 146 samples were analysed from Victoria and New South Wales which included yoghurt, cream, cheese, dessert, ice cream, egg white, onion dip and margarine. The highest level of styrene found was 0.1 mg kg^?1 in yoghurt. About 85% of all yoghurt samples were found to have values less than 0.05 mg kg^?1. The lowest values of styrene obtained were for margarine samples, of which more than 90% contained less than 0.010 mg kg^?1. The estimated limits of detection of the h.p.l.c. methods for all products except margarine were 0.005 mg kg^?1. The h.p.l.c. detection limit for margarine and the g.c. method for yoghurt were estimated to be 0.01 mg kg^?1.     

毛细管气相色谱法测定聚氯乙烯食品包装中的氯乙烯单体

研究采用毛细管气相色谱法检测聚氯乙烯薄膜中残留的氯乙烯单体,并用气相色谱质谱法进行确证.样品中的氯乙烯单体采用静态顶空技术提取.利用极性毛细管气相色谱柱进行分离并结合氢火焰离子化检测器进行高灵敏度检测.氟乙烯单体在0.05～0.2 mg/L的浓度范围内有较好的线性关系,相关系数为0.999,相对标准偏差在3.1%以内,检测低限为0.5 mg/kg,该方法具有较好的检测精密度和灵敏度.     

顶空气相色谱法测定软饮料中苯

苯是一种无色、有芳香气味、有毒、且致癌物质.食品中若含有苯,将对人的生命构成极大威胁,因此,控制苯的含量,制定苯的检测方法是刻不容缓的事,本文论述的是软饮料中苯的测定方法,用气-质联用仪鉴定,非极性色谱柱分离,顶空-气相色谱法分析,外标法定量.试验表明:该方法的前处理简单,重现性好RSD0.927%,且回收率也很高97.5%～116%.     

顶空气相色谱法测定橙汁类饮料中的苯含量

苯对人的神经和心血管系统有明显的毒性,对造血机能有抑制作用。本文研究了用顶空气相色谱法测定橙汁饮料中苯的含量。将样品置于顶空瓶中,用空气(空气与液体样品的比值为15/10)进行萃取,取1mL顶空气用于气相色谱检测。结果发现,同时含有苯甲酸钠和Vc的饮料样品中有苯的存在(3.4571×10-3mg/L);当取样量为1mL时,方法检测限为0.002mg/L,相对标准差为3.8%～5.4%,回收率79.6%～90.6%,变异系数为1.02%～9.67%。     

Determination of organophosphorus pesticides in pakchoi samples by headspace solid-phase microextraction coupled with gas chromatography using home-made fiber

A home-made sol-gel-derived co-poly (hydroxy-terminated silicone divinylbenzene) (OH-TSO/DVB) coating fiber has firstly been applied for headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography (GC)—nitrogen-phosphorus detector (NPD) to determine five organophosphorus pesticides (OPPs) in pakchoi samples. The following parameters influencing on the extraction efficiency of HS-SPME were optimized statistically: extraction temperature, extraction time, ionic strength, constant agitation, effect of sample matrix, desorption temperature, and desorption time. Compared with commercial available fibers and OH-TSO SPME fiber, this fiber showed statistically better enrichment capability for these pesticides. For the developed HS-SPME-GC method, it was found that the linearity was all two orders of magnitude, with the limits of detection (LOD) ranging from 0.007 to 0.07 ng g⁻¹, and relative standard deviations (RSD) varying between 4.1 and 8.7% (n = 5). Recoveries of spiked pakchoi samples ranged from 80.74 to 101.47% for every pesticide at each investigated concentration. Overall, it indicated that the obtained method is a validated and accurate procedure for determination of OPPs in pakchoi samples.     

Volatile compounds of Baltic herring analysed by dynamic headspace sampling–gas chromatography–mass spectrometry

European Food Research and Technology - The effect of storage time at 6&;nbsp;°C on the volatile compounds of Baltic herring was studied using the dynamic headspace–gas...     

Analysis of vinylidene chloride and 1-chlorobutane in foods packaged with polyvinylidene chloride casing films by headspace gas chromatography/mass spectrometry (GC/MS)

A headspace gas chromatography/mass spectrometry method was developed for the simultaneous determination of vinylidene chloride and 1-chlorobutane in foods packaged with polyvinylidene chloride casing films. The solid foodstuff was homogenized with an equal mass of distilled water. The homogenate was incubated for 1 h at 90°C in a sealed headspace vial, and the headspace gas was then analysed by gas chromatography/mass spectrometry in selected ion-monitoring mode using a bonded porous polymer-coated capillary column. The recovery rates of vinylidene chloride and 1-chlorobutane in foodstuffs were 94.5-103.9 and 85.8-120.3%, respectively. Among 13 samples tested, vinylidene chloride was detected at 0.001-0.020 µg g^-1 in 11 foodstuffs, and 1-chlorobutane was detected at 0.004-0.040 µg g^-1 in all 13 foodstuffs. Furthermore, vinylidene chloride was detected at 0.04 µg g^-1 in one casing film, and 1-chlorobutane was detected in all casing films. The results indicate that these compounds migrated from the casing films into the foodstuffs.     

凝胶渗透色谱—气相色谱/质谱法测定塑料桶装食用油中四种邻苯二甲酸酯

建立用凝胶渗透色谱净化―气相色谱/质谱分析塑料桶装食用油中四种邻苯二甲酸酯类增塑剂方法。样品用环己烷―乙酸乙酯(体积比为1∶1)稀释,稀释液经Bio–Bead S–X3凝胶柱净化后,采用气相色谱―质谱在选择离子检测(SIM)模式下进行定性定量分析;结果表明,四种增塑剂在0.1 mg/L~5 mg/L范围内线性关系良好;在空白油样中添加四种增塑剂(添加水平为0.5 mg/kg、5 mg/kg、10 mg/kg)混合标准溶液,平均回收率为85.7%~108.2%,相对标准偏差为3.8%~9.2%,检出限为0.1 mg/kg~0.2 mg/kg。     

HS-GC法测定辣椒红色素中的有机溶剂残留

目的:建立了同时测定辣椒红色素中甲醇、二氯甲烷、乙醇、丙酮和异丙醇5种残留溶剂的顶空气相色谱分析方法。方法:采用顶空进样法,平衡温度80℃,平衡时间30min,初始柱温温度为40℃保持4min,以10℃/min的速率升至180℃,保持4min,再以40℃/min的速率升至220℃,保持3min,以花生油∶DMF(5∶5)为溶剂,HP-MS为分析柱进行测定。结果:5种有机溶剂在各自的浓度范围内呈现良好的线性关系,方法精密度好(RSD<5.0%),检出限低0.09~2.3μg/g,样品加标回收率高98.0%~102%,RSD<5.0%(n=9)。结论:本方法简便、灵敏,为研究各种辣椒红色素中的残留溶剂提供了可靠的依据。     

顶空气相色谱法测定叶黄素中有机溶剂残留量

目的建立叶黄素中正己烷、乙醇和乙酸乙酯有机溶剂残留量的顶空气相色谱分析方法,并用该方法测定样品中的有机溶剂残留量。方法采用顶空气相色谱法,色谱柱为DB-624毛细管色谱柱(30 m×0.53 mm×3μm),载气为氦气,检测器为氢火焰离子化检测器,以程序升温方式使正己烷、乙醇和乙酸乙酯达到完全分离,外标法定量。结果正己烷、乙醇和乙酸乙酯的线性范围分别为4.95¹98 mg/L(r=0.99998)、8.295198 mg/L(r=0.99998)、8.295³31.8 mg/L(r=0.99994)和8.325331.8 mg/L(r=0.99994)和8.325³33 mg/L(r=0.99999);平均回收率范围为97.79%333 mg/L(r=0.99999);平均回收率范围为97.79%¹03.21%,精密度(以相对标准偏差计,n=3)为1.47%103.21%,精密度(以相对标准偏差计,n=3)为1.47%³.46%;检测限分别为0.09、0.83和0.33 mg/L。利用本方法对实际样品叶黄素中有机溶剂残留量进行了测定,结果表明,该样品中含有正己烷和乙醇,其含量分别为12 mg/kg和45 mg/kg。结论本方法快速、灵敏、准确,适用于叶黄素中残留溶剂的检测。     

毛细管气相色谱法测定食品中的酚类抗氧化剂

建立了同时测定食品中BHA、BHr、TBHQ和PG等四种酚类抗氧化剂的测定方法.采用HP-1毛细管色谱柱分离,氢火焰离子化检测器外标法定量,样品加标回收率为96.3%～104.2%,相对标准偏差为0.63%～1.53%,检出限分别为BHA为0.72mg/L、BHT为0.62mg/L、TB-HQ为0.68mg/L、PG为1.2mg/L.该方法具有快速、灵敏度高、重现性好、预处理简单等优点.     

Residual solvent or intrinsically formed during production: analysing volatile compounds in unrefined vegetable oils using headspace gas chromatography coupled with mass spectrometry

ABSTRACT

Vegetable oils are an essential part of a healthy and balanced diet and have major economic significance. The type of production, whether performed by extraction with solvents, or by mechanical techniques, significantly influences the quality of the oil and its potential field of use. Occasionally, volatile organic substances, which are considered indicative for an oil that has been produced by solvent extraction, are detected in unrefined vegetable oils. This can have a negative impact on high-quality oil mills and their reputation. The goal of the study was to analyse unrefined oils of different raw materials for such compounds. A previously developed and validated method using headspace gas chromatography coupled with a mass spectrometry was used for this task. Another aim was to determine the origin of any solvent residues in the vegetable oils and to find ways to avoid them. Complementary measurements by solid phase micro extraction gas chromatography were conducted to compare the results of the measurements to an orthogonal methodology. Multivariate data analysis was used to find correlations between the spectrum of substances in the oil and other parameters like the producer of the oil or the pattern of fatty acids.