Simultaneous determination of vitamins A and E in feeds and foods by reversed phase high-pressure liquid chromatography

A simple high-pressure liquid chromatographic method for the simultaneous determination of vitamins A and E in animal feeds and foods has been developed and evaluated. After saponification and extraction the sample was run on a reversed-phase column with water-methanol as the mobile phase. The detector was an u.v.-lamp at 280 nm. The method has been tested on different types of feeds and foods containing between 2-30 μg vitamin A g^?1 of sample and 5-300 μg vitamin E g^?1 of sample. The recovery of added vitamins was 86 % for retinylacetate and 91 % for α-tocopheryl-acetate with a standard deviation of 3 % for both. Results of the proposed procedure agreed well with those obtained by other methods.     

The determination of olaquindox in pig feeds by high-performance liquid chromatography

A simple, rapid method, based on high performance liquid chromatography, h.p.l.c., is described for the determination of olaquindox in pig feeds. The drug is extracted from the feed by use of a methanol-water mixture, an aliquot is injected on to the h.p.l.c.-column and quantified by u.v.-detection. The method has been tested on feeds and premixes containing olaquindox between 1–400 mg kg^?1.     

Determination of olaquindox,carbadox and cyadox in animal feeds by ultra-performance liquid chromatography tandem mass spectrometry

Olaquindox, carbadox, and cyadox are chemically synthesised antibacterial and growth-promoting agents for animals. At high doses they may exert mutagenicity and hepatic and adrenal toxicities in animals. Regrettably, these substances are frequently abused or misused when added into animal feeds. Thus, developing a sensitive and reliable method for simultaneous determination of olaquindox, carbadox, and cyadox in different kinds of animal feeds is crucially important for food safety monitoring. In this paper we optimised instrumental conditions, extraction solvents, solid phase extraction cartridges, and pH of the loading solvents on the Oasis HLB cartridge. Under the optimal conditions, mean recoveries ranged from 74.1 to 111%, and intra-day and inter-day variations were lower than 14.6% and 10.8%, respectively. The limits of quantification for olaquindox, carbadox, and cyadox were 0.05 mg kg^?1, 0.10 mg kg^?1, and 0.025 mg kg^?1, respectively. The proposed method uses ultra-performance liquid chromatography tandem mass spectrometry and is sensitive and reliable for the simultaneous determination of olaquindox, carbadox, and cyadox in three kinds of animal feeds (specifically, mixed feed, concentrated feed, and additive premixed feed). This method has good precision, high sensitivity, and good reproducibility, and thus it can be used for convenient and accurate determination of olaquindox, carbadox, and cyadox in different kinds of animal feeds.     

The composition of animal feeds

This paper postulates that, as the competition between animal and human feed is now a cause for socio-political concern, it is likely that there will be a return to the situation in which the animal feed industry utilises raw materials surplus to, or non-competitive with, human food. A brief discussion on each of the most important nutrients follows, outlining their importance in animal feeds before explaining the role of “fillers” in animal feeds. Least cost formulation is then explained, before an attempt is made at a raw material classification where the point is made that a dietary formulation depends more upon the specification of the required nutrients than it does on identifying individually selected raw materials. However, materials will be accepted or rejected according to their “economic value”.     

Detection of wheat gliadins in heated food by reversed-phase high-pressure liquid chromatography

To recognize and determine the wheat gliadins in unheated gluten-free food for coeliac patients the immunological methods such as ELISA can be used. In heated food (above 80 degrees-90 degrees C) these methods fail wholly or in part to achieve the quantitative determination of wheat gliadin. The changes in protein patterns after heat treatment are also revealed by the RP-HPLC of wheat gliadins and some peaks appear, which are characteristic for heat treated wheat flour. Using these peaks, about 2% admixture of wheat flour (T. aestivum, T. durum) as well as of rye flour can be detected. In foods which contain more than 50% skim milk the addition of only at least 5% of these flours can be detected. The ethanolic extracts of foods were concentrated by freeze-drying prior to analysis by HPLC. The ethanol-soluble non-dialysable food components affect the quantitative determination of wheat or rye proteins by means of peak areas. Selective enrichment is a possibility. The RP-HPLC-analysis of ethanol-soluble proteins makes it possible to detect heated flours of wheat and rye (cooked, roller-dried, extrusion-cooked) in glutenfree food.     

Development of a PCR assay for the detection of animal tissues in ruminant feeds

The European Community ban on use of meat and bone meal in ruminant feed, as a consequence of the spread of bovine spongiform encephalopathy in Europe, has prompted a number of investigations about the possibility of detecting animal tissues in feedstuff. In this paper, a study on vertebrate primers, designed in the 16S rRNA gene of mitochondrial DNA, is described. These primers were able to amplify fragments that contained between 234 and 265 bp. The fragments were specific for bovine, porcine, goat, sheep, horse, rabbit, chicken, trout, and European pilchard and were confirmed by sequence analysis amplicons. The primers were used in a PCR assay applied to five samples of meat and blood meals of different species and subjected to severe rendering treatments (134.4 to 141.9 degrees C and 3.03 to 4.03 bar for 24 min). The presence of vertebrate tissues was detected in all samples. The assay proved to be rapid and sensitive (detection limit 0.0625%). It can be used as a routine method to detect animal-derived ingredients in animal feedstuff.     

Occurrence of naphthalene in honey consumed in Turkey as determined by high-pressure liquid chromatography

This study is the first report on an investigation of the naphthalene concentration in samples of contaminated honey consumed in Turkey. Naphthalene was detected using high-performance liquid chromatography with a diode array detector at 220 nm. In one suspected contaminated specimen, the presence of naphthalene was confirmed by gas chromatography with mass spectrometry (GC-MS) at a concentration of 1.13 microg/kg. The limit of detection was 0.023 microg/g and the limit of quantification was 0.078 microg/g with signal-to-noise ratios of 3 and 10, respectively. A total of 100 samples of commercially available honey obtained from markets (53 samples) and street bazaars (47 samples) were analyzed. Mean naphthalene recovery from honey known to be contaminated with 1 microg/g was 80.4% (SD = 4.84%, n = 7).     

The determination of the coccidiostat nicarbazin in animal tissue and eggs. I. Determination by pulse polarography and high pressure fluid chromatography with electrochemical detection

The determination of nicarbazin residues in foodstuffs of animal origin by two different methods, polarography, HPLC with electrochemical detection, is described. By applying pulse polarography at the dropping mercury electrode to acetonitrile extracts of animal tissues and eggs, a detection limit of 50 micrograms/kg and mean recoveries of 79% were obtained. The same extracts were used for the HPLC determination with electrochemical detection. This led to a detection limit of 1 microgram/kg. Additional rapid confirmation can be obtained from HPLC using an internal standard (nifursol) and comparing peak area proportions of both substances at varied polarization voltages. The quantitative determination of nicarbazin in chicken eggs by both polarography and HPLC was found to be in good agreement.     

Development of a method for the determination of pyrimethamine concentrations in feeds by ion-pairing high-performance liquid chromatography

An ion-pairing reversed-phase high-performance liquid chromatography (HPLC) method with diode array detection at 280 nm was developed to determine pyrimethamine concentrations in feed for laying hens. Pyrimethamine was extracted with a mixture of 5% isobutanol and 95% benzene, and the extract was cleaned up on an alumina column. The drug was eluted from an Intersil ODS-3V column (250 by 4.6 mm) with a mixture of 25% acetonitrile and 75% water (vol/vol) containing 0.01 M tetramethylammonium chloride as an ion-pairing agent and adjusted with acetic acid to pH 3.5. The flow rate was 1.0 ml/min. Mean recovery of pyrimethamine from supplemented feeds at concentrations of 2, 4, and 5 microg/g of feed were 100.5, 103.5, and 100.8%, respectively. Precision within a day ranged from 4.3 to 7.0% for the three concentrations, and day-to-day precision was 5.3% for feed supplemented at a concentration of 4 microg/g. No chromatographic interference was detected from other 2,4-diaminopyrimidine compounds or other major drugs used in poultry.     

Determination of ochratoxin A in red wine and vinegar by immunoaffinity high-pressure liquid chromatography

A method is described for the determination of ochratoxin A (OTA) in red wine and vinegar using an acidic chloroform extraction, an immmunoaffinity clean-up step, and a high-performance liquid chromatographic determination with fluorescence detection. The detection limit was estimated at 0.002 microg/liter. The mean recovery factors were found at 91.3 and 96.6% for wine and vinegar, respectively. Thirty-one samples of red wine originating from Mediterranean sea countries and 15 samples of vinegar were examined for the presence of OTA. All red wine samples contained OTA. Seventy-two percent of these samples were found to be contaminated over 0.1 microg/liter. Among them, nine samples contained ochratoxin A in the range of 0.5 to 3.4 microg/liter, 12 samples in the range of 0.10 to 0.50 microg/liter (median: 0.176 microg/liter), and 9 samples in the range of 0.010 to 0.100 microg/liter (median: 0.041 microg/liter). All 15 vinegar samples showed the presence of OTA. The most contaminated ones were three balsamic vinegar samples containing 0.156 microg/liter, 0.102 microg/liter, and 0.252 microg/liter of OTA. In the remaining 12 samples, ochratoxin A levels ranged from 0.008 microg/liter to 0.046 microg/liter (median: 0.012 microg/liter). These data are in good agreement with the hypothesis that wine originating from Southern countries might contain significant OTA concentration and showed the possible occurrence of traces of OTA in vinegar.     

The composition of animal feeds [proceedings

The following are summaries of papers read at a symposium held on 24 November 1976, organised by the Microbiology, Fermentation and Enzyme Technology Group. The reports so published are entirely the responsibility of the authors and in no way reflect the views of the Editorial Board of the Journal of the Science of Food and Agriculture.     

HPLC法测定动物组织中氯氰碘柳胺的残留量

将样品经乙腈提取,色谱柱为COSMOSIL 5C18-AR-Ⅱ(250 ×4.6 mm,5μm);柱温为35℃;紫外检测波长设在260 nm:流动相为甲醇:0.1%甲酸水溶液(95:5,V:V);流速1.0 mL/min;进样量50μL.结果氯氰碘柳胺样品平均回收率为74.35%～95.92%,相对标准偏差(ItSD)为3.19%～7.69%;最低检测限(LOD)为50μg/kg.该方法简便,准确,灵敏度高,是快速检测和监测动物组织中氯氰碘柳胺的残留可借鉴的分析方法.     

Detection and assay of single cell protein products in blends with animal feeds.

Electrophoretic patterns of protein extracts obtained with different procedures from the BP-yeast product named Toprina (a Candida lipolytica strain grown on n-alkanes) have been compared with protein electrophoretic patterns of a number of different microbial species. The gel electrophoretic pattern of the 0.15 M NaCl extract from Toprina was specific enough to allow an easy differentiation of Toprina from the other microorganisms tested. To detect and assay Toprina in blends with animal feeds, an immune serum containing antibodies reacting specifically with Toprina has been prepared by immunising rabbits with an antigen preparation extracted from Toprina with 0.15 M NaCl and precipitated by salting out the extract at 4.0 M (NH₄)₂SO₄. Three main antibodies reacting with Toprina antigens have been found in the anti-Toprina immune serum, but only one was specific of Toprina. The resistance of the Toprina antigens to peptic digestion and their behaviour on extraction, electrophoresis and gel filtration suggest that they might be acidic polysaccharide in nature. Immunodiffusion analyses with the anti-Toprina immune serum of extracts obtained with 0.15 M NaCl from very heterogeneous animal feeds added with different amounts of Toprina, allowed the detection of a Toprina amount as low as 2.5%. An accurate assay of Toprina was achieved by submitting the feed extract to radial immunodiffusion with the anti-Toprina immune serum.     

Validation of the procedure for the determination of maduramicin in concentrates,premixes, and feeds by liquid chromatography

A single laboratory validation was carried out for the determination of maduramicin in concentrates, premixes, and feed. The method comprised sample extraction of maduramicin, derivatization with dansylhydrazine and liquid chromatography with ultraviolet light detection. The limit of detection (LOD) and limit of quantification (LOQ) were 0.4 and 1.0 mg kg^?1, respectively. The repeatability expressed as the average difference between the results of duplicate measurements was 5.9% at the concentration level of 1% (concentrate), 7.1% at the concentration level of 1 g kg^?1 (premix), and 11% with the feed containing maduramicin with the nominal concentration of 5 mg kg^?1 and feed spiked at the concentration level of 1 mg kg^?1. The relative standard deviations for the within-laboratory reproducibility (RSD_W) were 9.2%, 16%, 18%, and 17% at the concentration levels of 1%, 1 g kg^?1, 5 mg kg^?1, and 1 mg kg^?1, respectively. The measurement uncertainties were ±0.2%, ±0.3 g kg^?1, ±1.9 mg kg^?1, and ±0.3 mg kg^?1 at the same concentration levels, respectively.     

免疫亲和柱层析-超高效液相色谱法测定动物性食品中6种黄曲霉毒素

目的建立一种快速、灵敏的超高效液相色谱法,同时测定动物性食品中黄曲霉毒素B_1、B_2、G_1、G_2、M_1和M_2。方法甲醇-水(80∶20,V/V)提取粉碎或匀浆动物性食品中的黄曲霉毒素,取部分样液经过免疫亲和柱层析净化,经C_(18)色谱柱(3.0 mm×50 mm,1.7μm)分离,荧光检测器检测。保留时间定性,峰面积定量。结果5 min内完成分离,黄曲霉毒素B_1、B_2、G_1、G_2、M_1和M_2检出限分别为0.038、0.010、0.062、0.010、0.110、0.016μg/kg。标准曲线线性范围分别为AFB_1:1.28~20.4μg/L;AFB_2:0.32~5.08μg/L;AFG_1:1.26~20.2μg/L;AFG2:0.31~5.00μg/L;AFM_1:1.25~20.0μg/L;AFM_2:1.25~20.0μg/L,相关性在0.999 7~0.999 9之间。不同浓度水平6种黄曲霉毒素平均加标回收率在73.2%~94.1%之间,精密度在0.2%~3.8%之间。结论该方法可同时、快速、高效、准确测定动物性食品中6种黄曲霉毒素的含量。     

A method for the verification of chloramphenciol residues in animal tissues and eggs with high pressure liquid chromatography with radioimmunologic assay

The determination of chloramphenicol residues in animal tissues and eggs by high performance liquid chromatography followed by radioimmunological detection (HPLC-RIA) is described. The method is suited for the verification of positive results greater than or equal to 1 microgram/kg obtained from prescreening with a radioimmunoassay.     

Ergot alkaloids in rye flour determined by solid-phase cation-exchange and high-pressure liquid chromatography with fluorescence detection

Ergot alkaloids are mycotoxins that are undesirable contaminants of cereal products, particularly rye. A method was developed employing clean-up by cation-exchange solid-phase extraction, separation by high-performance liquid chromatography under alkaline conditions and fluorescence detection. It is capable of separating and quantifying both C8-isomers of ergocornine, alpha-ergocryptine, ergocristine, ergonovine, and ergotamine. The average recovery was 61% +/- 10% with limits of detection from 0.2 to 1.1 microg kg(-1). Twenty-four unknown rye flour samples from Danish mills contained on average 46 microg kg(-1) with a maximum content of 234 microg kg(-1). The most common ergot alkaloids were ergotamine and alpha-ergocryptine including their C8-isomers. A total of 54% of the ergot alkaloids were detected as C(8)-S isomers.     

Ergot alkaloids in rye flour determined by solid-phase cation-exchange and high-pressure liquid chromatography with fluorescence detection

Ergot alkaloids are mycotoxins that are undesirable contaminants of cereal products, particularly rye. A method was developed employing clean-up by cation-exchange solid-phase extraction, separation by high-performance liquid chromatography under alkaline conditions and fluorescence detection. It is capable of separating and quantifying both C8-isomers of ergocornine, α-ergocryptine, ergocristine, ergonovine, and ergotamine. The average recovery was 61% ±?10% with limits of detection from 0.2 to 1.1 µg kg^?1. Twenty-four unknown rye flour samples from Danish mills contained on average 46 µg kg^?1 with a maximum content of 234 µg kg^?1. The most common ergot alkaloids were ergotamine and α-ergocryptine including their C8-isomers. A total of 54% of the ergot alkaloids were detected as C(8)-S isomers.     

高压液相色谱法测定食品接触材料水性模拟液中2,4-二羟基二苯甲酮

目的 探讨高压液相色谱法测定食品接触材料水性模拟液中2,4-二羟基二苯甲酮的方法。方法 食品接触材料经水、10%乙醇(v/v)、20%乙醇(v/v)、50%乙醇(v/v)以及3%乙酸(w/v)5种不同水性模拟液提取后, 以Agilent HC-CN为分析柱, 甲醇: 水(55: 45, v/v)为流动相, 经UV检测器(?=290 nm) 进行定量分析。结果 5种不同水性模拟液中2,4-二羟基二苯甲酮在0.5~10.0 mg/L浓度范围内线性关系均良好(r=0.9999), 检测限(S/N=3)均为0.02 mg/L。在低、中、高3个不同添加水平下进行加标回收实验, 2,4-二羟基二苯甲酮的平均回收率为84.0%~96.9%, RSD(n=6)为0.85%~4.60%。结论 本方法简单、快速、准确, 完全能够满足食品接触材料日常检验的需要。     

Detection of high fructose- and other syrups in honey using high-pressure liquid chromatography

Summary A highly sensitive method was developed for the detection of conventional syrups and high fructose syrups in honey at a level as low as 1 % of the total mixture. Hydrolysates from corn, potato, wheat and rice starch were analysed. Higher saccharides, which do not occur in honey but are found in low concentrations in syrups, were concentrated by medium-pressure liquid chromatography using a charcoal/celite mixture. These sugars were measured by a refractometer connected to reversed-phase high-pressure liquid chromatography equipment. Compared with other methods, the described procedure allows for a rapid, sensitive, and quantitative detection of adulterants in honey.

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Nachweis von Hochfructose- und anderen Syrupen in Honig mit HPLC

Zusammenfassung Es wurde eine höchst sensitive Methode entwickelt, die es erlaubt, konventionelle Sirupe oder Hochfructosesirupe noch in der Konzentration von 1 Gewichts-% im natürlichen Honig nachzuweisen. Es wurden Hydrolysate aus Mais-, Kartoffel-, Weizen-und Reisstärke untersucht. Höhere Oligosaccharide, die nicht in Honigen, aber in Sirupen in geringer Konzentration vorliegen, werden durch Mitteldruckflüssigchromatographie (MPLC) über eine Aktivkohle/Kieselgur-Mischung angereichert. Die Messung dieser Zucker erfolgt mittels Refraktometer, gekoppelt mit einer Umkehr-Hochdruckflüssigchromatographie-Anlage (RP-HPLC). Im Vergleich zu anderen Methoden ermöglicht die hier vorgestellte eine schnelle, sensitive und quantitative Erfassung von Honigverfälschungen.