Determination of 2,4,6-triiodoresorcinol and other side reaction products and intermediates in the colour additive FD&C Red No. 3 (erythrosine) using high-performance liquid chromatography

An HPLC method was developed for the quantitative determination of 2,4,6-triiodoresorcinol (I3R), 2-(2',4'-dihydroxy-3',5'-diiodobenzoyl)benzoic acid, resorcinol, phthalic acid, and sodium iodide in the colour additive FD&C Red No. 3 (erythrosine) (R3). Due to the fast decomposition of I3R in aqueous solutions, the dye portions analysed were dissolved in methanol and the determinations were performed in the freshly-made solutions. The HPLC method is rapid (50 min total analysis cycle, ∼16 min to detect I3R and the other intermediates), simple to implement, and generates only small amounts of solvent waste. It was found to be applicable for use in routine batch-certification as shown by the analysis of test portions from 24 lots of R3 submitted for US-certification by domestic and foreign manufacturers during the past three years.     

气相色谱法测定食品中山梨酸、苯甲酸方法

通过对液态、固液混合态食品前处理方法的改进,用气相色谱法快速测定山梨酸、苯甲酸的含量。样品酸化后用乙醚提取,直接取上清液进样分析,使用美国安捷伦公司6890型气相色谱仪,氢火焰离子化检测器(FID)和DB-FFAP123-3233色谱柱(30m×320μm)1h内可测得两种防腐剂的平均回收率为99.82%(n=6),平均相对标准偏差为1.265%,检测限为1mg/kg。     

胶束电动色谱在线推扫富集技术测定饮料中的防腐剂苯甲酸

考察了样品预处理、背景缓冲溶液pH、十二烷基硫酸钠（SDS）浓度、进样时间对苯甲酸测定过程中的富集效果的影响。结果显示：在电泳缓冲溶液为20mmol／L硼砂＋60mmol／L十二烷基硫酸钠（pH=9．30），紫外检测波长214nm，分离电压18kV时，富集倍数可达150倍。在线推扫富集胶束电动色谱法减少了样品处理的繁琐过程，操作简单，成本低。大大缩短了分析周期，弥补了毛细管电泳测定微量组分的不足。     

Estimate of intake of benzoic acid in the Belgian adult population

An exposure assessment was performed to estimate average daily benzoic acid intake for Belgian adults. Food consumption data were retrieved from the national food-consumption survey. As a first step, individual food-consumption data were multiplied with the maximum permitted use levels for benzoic acid per food group (Tier 2). As a second step, a label survey to identify the foods where benzoic acid is effectively used as an additive and a literature review of the possible occurrence of benzoic acid as a natural substance were performed. With this information, a refined list of foods was drafted for the quantification of benzoic acid, which was performed by a high-performance liquid chromatography (HPLC) method, optimized and validated for this purpose. Individual food-consumption data were then multiplied with the actual average concentrations of benzoic acid per food group (Tier 3). Usual intakes were calculated using the Nusser method. The mean benzoic acid intake was 1.58 mg kg^?1 body weight day^?1 (Tier 2) and 1.25 mg kg^?1 body weight day^?1 (Tier 3). In Tier 2, men exceeded the acceptable daily intake (ADI) of 5 mg kg^?1 body weight day^?1 at the 99th percentile. The greatest contributors to the benzoic acid intake were soft drinks. Benzoic acid as a natural substance represents only a small percentage of the total intake. The results show that actual benzoic acid intake is very likely to be below the ADI. However, there is a need to collect national food-consumption data for children as they might be more vulnerable to an excessive intake.     

葡萄酒中苯甲酸的测定测量审核结果分析

目的 参加MA-GW-010项目"葡萄酒中苯甲酸的测定"测量审核,提升实验室对食品中苯甲酸的检测能力和实验室综合检测水平.方法 以GB 5009.28—2016《食品安全国家标准食品中苯甲酸、山梨酸和糖精钠的测定》第一法为依据,采用高效液相色谱法二极管阵列检测器对样品进行检测,并按照实验室多种内部质量控制方式对检测结果...     

Determination of synthetic by-products and an intermediate in the colour additive D&C Orange No. 5 using high-performance liquid chromatography

Specifications in the US Code of Federal Regulations for the colour additive D&C Orange No. 5 (Colour Index No. 45370:1) limit the levels of the synthetic by-products 2-(3,5-dibromo-2,4-dihydroxybenzoyl)benzoic acid (Br2BBA) and brominated resorcinol (Br3R) as well as the level of the intermediate phthalic acid (PhthAc). The present work reports the development and application of a high-performance liquid chromatography (HPLC) method for the quantitative determination of these impurities in D&C Orange No. 5 and its lakes. Br2BBA, Br3R and PhthAc were quantified by using five-point calibration curves with data points that ranged from 0.010% to 0.700%, from 0.012% to 0.706% and from 0.006% to 1.383% by weight, respectively. The HPLC method was applied to the analysis of test portions from 11 lots of D&C Orange No. 5 and one lot of D&C Orange No. 5 lake submitted to the US Food and Drug Administration (USFDA) for certification.     

Monitoring of free glutamic acid in Malaysian processed foods,dishes and condiments

A study to quantify the free glutamic acid content of six processed foods, 44 dishes and 26 condiments available in Malaysia was performed using high-performance liquid chromatography with a fluorescence detector (HPLC-FRD). Recovery tests were carried out with spiked samples at levels from 6 to 31 mg g^?1. High recovery in different matrices was achieved ranging from 88% ± 13% to 102% ± 5.12%, with an average of 97% ± 8.92%. Results from the study revealed that the average free glutamic acid content ranged from 0.34 ± 0.20 to 4.63 ± 0.41 mg g^?1 in processed foods, while in prepared dishes it was as low as 0.24 ± 0.15 mg g^?1 in roti canai (puffed bread served with curry or dhal) to 8.16 ± 1.99 mg g^?1 in dim sum (a small casing of dough, usually filled with minced meat, seafood, and vegetables, either steamed or fried). Relatively, the content of free glutamic acid was found to be higher in condiments at 0.28 ± 0 mg g^?1 in mayonnaise to 170.90 ± 6.40 mg g^?1 in chicken stock powder.     

Estimated intake of benzoic and sorbic acids in Denmark

The monitoring of food additives and recent dietary surveys carried out in Denmark have earlier been used to estimate the intake of sweeteners and nitrite in relation to acceptable daily intakes. The ubiquitous use of the preservatives benzoic and sorbic acids raises the question of the magnitude of the intake of these preservatives in relation to acceptable daily intakes. This area is explored in this paper. The content of benzoic and sorbic acids in all food groups, where they are allowed, was monitored in Denmark 17 times between 2001 and 2006 with a total of 1526 samples. Transgressions of maximum limits, illegal use or declaration faults were found in about 3% of samples. From repeated investigations on fat-based foods (salads and dressings), marmalade and stewed fruit, it is concluded that the amounts used in industry have been relatively stable throughout the whole period, although limited data for marmalade show some variation. Most foods in the categories soft drinks, dressings, fat-based salads, pickled herrings, and marmalade contain benzoic and sorbic acid, and sliced bread also contains in some cases sorbic acid. The median daily intake and intake distribution of benzoic and sorbic acids were calculated with data from the Danish National Survey of Dietary Habits and Physical Activity (age from 4 to 75 years) conducted in 2000–2004 with 5785 participants. The median intakes of both benzoic acid and sorbic acid are well below the acceptable daily intakes of 0–5 and 0–25 mg kg^?1 body weight (bw) day^?1 for benzoic and sorbic acid, respectively. However, the 90th percentile based on the average of the samples with a content of benzoic acid is higher than the acceptable daily intake for both men and women, with the highest value of 16 mg kg^?1 bw day^?1 for both boys and girls in the 4–6-year-old age group. Based on the average of all samples, the 95th percentile is over the acceptable daily intake for men up to 34 years and for women up to 24 years, and the 90th percentile for men up to 18 years and for women up to 10 years. Soft drinks, salads and dressings are the main contributors to benzoic acid intake. The sorbic acid intake based on the average of all samples is well below the acceptable daily intake. However, for the intake based on the average of samples with content, the 95th percentile exceeds the acceptable daily intake. This is caused by the dominating contribution to the intake of sorbic acid from sliced bread, but since only seven out of 42 samples have added sorbic acid, the calculation based on the average of samples with content will exaggerate the intake. With a built-in safety factor of 100 in the acceptable daily intakes and judging from the literature, the high intakes of benzoic acid should not cause any concern for ill-effects. However, there must be a reason to reconsider the maximum limits especially for benzoic acid in soft drinks, dressings and salads and for sorbic acid in sliced bread.     

高效液相色谱法测定丽石黄衣中松萝酸的含量及抑菌活性的研究

以丽石黄衣(Xan thoria elegans (Link)Th.Fr.)为材料,乙酸乙酯为溶剂回流提取松萝酸,采用高效液相色谱法测定松萝酸的含量并用滤纸片法对松萝酸的抑菌作用进行了测定。实验结果表明,丽石黄衣中松萝酸的总含量为4.06%,松萝酸对酵母没有抑菌作用,可对其他受试细菌和真菌有抑菌作用。     

A rapid h.p.l.c. method for the determination of methionine hydroxy analogue free acid in supplemented feeds

Two methods are described for determining methionine hydroxy analogue free acid (HMB) in supplemented poultry feeds. The procedure is based on extraction of analogue from the feed, followed by high-pressure liquid chromatographic measurement of the HMB directly after extraction or, more rigorously, after extraction and hydrolysis of oligomers to monomer. Recoveries of HMB over the supplementation range 0.08–0.25% (by wt) are 98% with coefficients of variation of 5.4% in commercial poultry feeds. A 98% correlation coefficient is obtained when the analyses are compared with the gas chromatographic method.     

水翁花蕾提取物DMC对胰脂肪酶的抑制作用研究

本文主要探讨了2',4'-二羟基-6'-甲氧基-3',5'-二甲基查耳酮(2',4'-dihydroxy-6'-methoxy-3',5'-dimethylchalcone,DMC)对胰脂肪酶(Pancreatic Lipase,PL)的抑制作用及作用机理。以4-硝基苯丁酸酯为底物,采用对硝基苯酚法检测DMC对PL活性的影响,采用紫外光谱法、荧光光谱法以及分子对接法研究DMC与PL的相互作用。结果表明:DMC对PL有抑制作用,半数抑制浓度为50.01±3.56 μmol/L,酶动力研究表明DMC是PL的竞争型抑制剂;光谱实验结果显示DMC的加入使PL发生了荧光猝灭,猝灭类型为动态猝灭;同步荧光及三维荧光实验表明DMC不会改变PL构象;热力学参数ΔG<0,两者的相互作用是自发进行,ΔH<0,ΔS<0,表明DMC与PL的相互作用力主要为氢键和范德华力;分子对接实验进一步验证了以上结果。由此可见,DMC具有作为PL抑制剂的潜能。     

Identification of a novel phenolic compound in litchi (Litchi chinensis Sonn.) pericarp and bioactivity evaluation

Litchi (Litchi chinensis Sonn.) is a delicious fruit widely accepted by consumers all over the world. In this work, phytochemical investigation of litchi pericarp methanol extracts led to the isolation of a novel phenolic, 2-(2-hydroxyl-5-(methoxycarbonyl) phenoxy) benzoic acid, together with kaempferol, isolariciresinol, stigmasterol, butylated hydroxytoluene, 3,4-dihydroxyl benzoate, methyl shikimate and ethyl shikimate. Most were found in litchi pericarp for the first time. Their structures were mainly elucidated by NMR and MS evidences. Antioxidant activities of the eight compounds were determined by a DPPH radical scavenging assay and the results showed that 2-(2-hydroxy-5-(methoxycarbonyl) phenoxy)benzoic acid, kaempferol, isolariciresinol, butylated hydroxytoluene and 3,4-dihydroxy benzoate exhibited good antioxidant activities. An interesting finding was that butylated hydroxytoluene was detected as a natural antioxidant in this work, which was usually taken as a synthesized antioxidant. Furthermore, the novel compound exhibited no inhibitory effects against tyrosinase and α-glucosidase activities.     

Effect of some habitual cooking processes on the domoic acid concentration in the cockle (Cerastoderma edule) and Manila clam (Ruditapes philippinarum)

The effect of cooking on the concentration and burden of domoic acid in two bivalve molluscs was studied. The Manila clam (Ruditapes philippinarum) and cockle (Cerastoderma edule) were subjected to steaming and boiling, respectively. In both cases, factorial plans were used to evaluate the effects of common cooking methods and the variations likely to take place during the cooking procedure (cooking time and salt concentration in both species, in addition to ethanol percentage in Manila clam). The domoic acid concentration and toxin content were affected by cooking in very different ways in the two species studied. The cockle lost a significant part of its domoic acid content, while the clam did not. Since the weight of the soft tissues in cooked bivalves was lower than in the raw samples in both species, the toxin concentration decreased less than the toxin burden in the cockle, while it increased in the clam, where the toxin burden did not change significantly. Among the cooking variables tested, only cooking time had a noticeable effect on the domoic acid content in the clam and cockle, with the bivalves that were cooked for a longer time having smaller amounts of toxin. It is clear that cooking affects the toxin concentration in bivalves in a way that is species specific. This characteristic must be taken into account when evaluating epidemiological information, establishing allowable toxin levels and in cases where pre-processing treatments such as cooking or similar methods are used in monitoring systems.     

UPLC-MS-MS检测饮料中的4-甲基咪唑及其同分异构体2-甲基咪唑

建立超高效液相色谱-串联质谱（ultra performance liquid chromatography -tandem mass spectrometry,UPLCMS- MS）法检测饮料中的4-甲基咪唑（4-(5-)-methylimidazole,4-Mel）及2-甲基咪唑（2-methylimidazole,2-Mel） 的方法。以水溶解样品,OASIS®MCX固相萃取柱富集净化后,进入UPLC-MS-MS检测,内标法定量。在优化的条 件下,以ACQUITY UPLC® HILIC色谱柱（2.1 mm×100 mm,1.7 mm）为分析柱,乙腈和5 mmol/L甲酸铵溶液为 流动相,在电喷雾正离子多反应监测模式进行检测。结果表明,4-Mel和2-Mel在9～500 ng/mL范围内线性关系良 好。方法的定量限为3.0 mg/kg。在4 个加标水平下,3 种不同基质饮料中4-Mel和2-Mel的平均回收率分别为97.3% 和93.7%,相对标准偏差分别为3.8%和3.4%,该方法适用于饮料中4-Mel和2-Mel的检测。利用该方法对市售饮料中 4-Mel和2-Mel的含量进行检测,在软饮料、焦糖色饮料及咖啡饮料中检出含有4-Mel或2-Mel;而功能性饮料中未检 出4-Mel和2-Mel。     

High-performance liquid chromatographic method for the simultaneous detection of the adulteration of cereal flours with melamine and related triazine by-products ammeline, ammelide, and cyanuric acid

Melamine has been used for the adulteration of cereal flours in order to increase their apparent protein content. Crude melamine may contain several by-products, i.e. ammeline, ammelide, and cyanuric acid. The simultaneous analysis of all four chemicals is difficult because of the formation of an insoluble salt between melamine and cyanuric acid. A simple and convenient high-performance liquid chromatography (HPLC) method for the detection of the adulteration of cereal flours with all four chemicals is proposed herein. The precipitate formation between melamine and cyanuric acid was prevented by using alkaline conditions (pH 11-12) for both standards preparation and sample extraction. The method uses matrix-matching, which involves the construction of a calibration curve on a blank (negative control) matrix, which is then used for the quantitation of melamine and by-products in adulterated (positive) samples. Matrix-matching compensates for analyte losses during sample preparation, and for matrix effects. The method was successfully applied to wheat, corn, and rice flours, and is expected to be applicable (with some modifications) to soy flour as well. The method allows for the detection of melamine, ammeline, and ammelide at approximately 5 µg g^-1, and cyanuric acid at approximately 90 µg g^-1 in wheat flour.     

不同红茶中主要氨基酸含量及其对小鼠自主活动的影响研究

通过高效液相色谱法（HPLC）测定不同红茶中γ-氨基丁酸（γ-aminobutyric acid,GABA）、L-茶氨酸和L-谷氨酸的含量,并通过小鼠自主活动测试仪比较不同主要氨基酸含量的红茶水提物对小鼠自主活动的影响。结果表明,不同红茶中GABA、L-茶氨酸和L-谷氨酸含量差别均较大,并且L-茶氨酸含量普遍高于GABA、L-谷氨酸含量。其中,GABA含量以高黎贡山为最高,汉水韵红茶次之,紫鹃红最低;L-茶氨酸和L-谷氨酸含量均以八仙红茶为最高,汉水韵红茶次之,印度大吉岭红茶最低。此外,动物实验结果显示,与主要氨基酸含量较低红茶组相比,主要氨基酸含量较高红茶组小鼠的自主活动次数显著减少（p<0.05）。以上结果提示,主要氨基酸含量较高的红茶对小鼠具有明显的镇静作用。      

Gut microbial catabolism of grape seed flavan-3-ols by human faecal microbiota. Targetted analysis of precursor compounds, intermediate metabolites and end-products

In vitro batch culture fermentations were conducted with grape seed polyphenols and human faecal microbiota, in order to monitor both changes in precursor flavan-3-ols and the formation of microbial-derived metabolites. By the application of UPLC-DAD-ESI-TQ MS, monomers, and dimeric and trimeric procyanidins were shown to be degraded during the first 10 h of fermentation, with notable inter-individual differences being observed between fermentations. This period (10 h) also coincided with the maximum formation of intermediate metabolites, such as 5-(3′,4′-dihydroxyphenyl)-γ-valerolactone and 4-hydroxy-5-(3′,4′-dihydroxyphenyl)-valeric acid, and of several phenolic acids, including 3-(3,4-dihydroxyphenyl)-propionic acid, 3,4-dihydroxyphenylacetic acid, 4-hydroxymandelic acid, and gallic acid (5-10 h maximum formation). Later phases of the incubations (10-48 h) were characterised by the appearance of mono- and non-hydroxylated forms of previous metabolites by dehydroxylation reactions. Of particular interest was the detection of γ-valerolactone, which was seen for the first time as a metabolite from the microbial catabolism of flavan-3-ols. Changes registered during fermentation were finally summarised by a principal component analysis (PCA). Results revealed that 5-(3′,4′-dihydroxyphenyl)-γ-valerolactone was a key metabolite in explaining inter-individual differences and delineating the rate and extent of the microbial catabolism of flavan-3-ols, which could finally affect absorption and bioactivity of these compounds.     

Assessment of the dietary habits and polycyclic aromatic hydrocarbon exposure in primary school children

Thirty Italian children, 7–9 year aged, living in Naples were investigated on their dietary habits and on polycyclic aromatic hydrocarbon (PAH) exposure by a food diary-questionnaire and one week duplicate diet sample analyses. Daily total food consumption mean value was 632 ± 215 g day^?1, median value 613 g day^?1. The daily energy intake and the diet composition meanly agreed with the official guidelines for the Italian children. Sixteen PAHs were simultaneously detected and, according to the European Food Safety Authority (EFSA) approach, benzo[a]pyrene; benzo[a]pyrene + chrysene (PAH2); PAH2 + benz[a]anthracene + benzo[b]fluoranthene (PAH4); PAH4 + benzo[k]fluoranthene + benzo[ghi]perylene + dibenz[a, h]anthracene + indeno[1,2,3-cd]pyrene (PAH8) were considered in evaluating the children's dietary exposure to PAHs. The benzo[a]pyrene (BaP) median concentrations in foods varied from 0.06 to 0.33 µg kg^?1. Only three samples of cooked foods (one fish and two meat samples) exceeded legal limits fixed by the European Union for BaP. Daily median intakes of benzo[a]pyrene, PAH2, PAH4, and PAH8 were 153; 318; 990; 1776 ng day^?1; their median exposure values were 5; 10; 28; 54 ng kg^?1 bw day^?1. The Margins of Exposure (MOEs) in median consumers agreed with the EFSA safety values except for PAH8.     

Assessment of the quantitative determination of paralytic shellfish poisoning toxins by pre-column derivatization and elimination of interfering compounds by solid-phase extraction

Monitoring programmes for paralytic shellfish poisoning toxins in bivalve molluscs still rely heavily on the use of mouse bioassays (MBA) for consumer protection. A high-performance liquid chromatography (HPLC) methodology (Lawrence method) was implemented in 1996 in the Portuguese monitoring programme as a complementary means of analysis. Comparison between MBA and HPLC was done at the time only by a qualitative approach due to the scarce number of positive samples tested. More quantitative data were obtained recently when studying toxin profiles in Moroccan shellfish, and the correlation found between these two methodologies is reported here for the first time. Two different matrices were studied: blue mussel and the giant cockle Acanthocardia tuberculatum. A good linear correlation was obtained for both matrices. However, a second-degree polynomial best fitted the data at both low and high extremes of toxicity. According to the HPLC quantitative results, 13% of false-negatives could be obtained by MBA due to an underestimation of toxicity near the limit of detection of the MBA. Difficulties on relying solely on HPLC for consumer protection have been aroused with uncommon matrices, such as imported clams or crustaceans, due to the presence of high concentrations of interfering compounds. The solid-phase extraction step of the Lawrence method was implemented to eliminate an unknown compound that could be mistaken for saxitoxin, and an 80% reduction of another common unknown compound eluting close to decarbamoylsaxitoxin. The implementation of the HPLC methodology achieved so far allows a high degree of consumer protection without the need to resource to animal sacrifice.     

绿豆种子萌发过程中酚类化合物的动态变化

建立了同时测定绿豆醇提液中19种酚类化合物的高效液相色谱（High performance liquid chromatography,HPLC）方法,并结合标准品对绿豆种子萌发过程中19种酚类化合物进行了定性定量分析。结果表明,在绿豆种子萌发过程中,酚类化合物种类和总量均有所增加,其中没食子酸和咖啡酸含量随萌发时间的显著延长而增加;芦丁、黄豆苷元、山奈酚、p-香豆酸、阿魏酸和染料木素含量在第7 d有最大值,分别为1574.5、114.3、80.3、43.3、207.9和45.3μg/g;槲皮素含量在第4 d有最大值28.0μg/g;原儿茶酸、橙皮苷、肉桂酸和柚皮素含量在第5 d有最大值,分别为89.1、297.4、84.6和30.6μg/g;白藜芦醇、对硝基苯甲酸和鹰嘴豆芽素A含量在第2 d有最大值,分别为89.6、70.8和237.0μg/g;杨梅酮、儿茶素和橙皮素含量在第6 d有最大值,分别为40.7、712.1和58.2μg/g。而19种酚类化合物总含量在第7 d有最大值,达到3508.8μg/g。在绿豆种子萌发过程中,由于酶种类增多、活性增强,导致次级代谢产物大量合成,酚类化合物含量增多。