Discovery and structural elucidation of the illegal azo dye Basic Red 46 in sumac spice

An unknown red dye was discovered in a sumac spice sample during routine analysis for Sudan dyes. LC-DAD and LC-MS/MS did not reveal the identity of the red substance. Nevertheless, using LC-high-resolution MS and isotope ratio comparisons the structure was identified as Basic Red 46. The identity of the dye was further confirmed by comparison with a commercial hair-staining product and two textile dye formulations containing Basic Red 46. Analogous to the Sudan dyes, Basic Red 46 is an azo dye. However, some of the sample clean-up methodology utilised for the analysis of Sudan dyes in food prevents its successful detection. In contrast to the Sudan dyes, Basic Red 46 is a cation. Its cationic properties make it bind strongly to gel permeation columns and silica solid-phase extraction cartridges and prevent elution with standard eluents. This is the first report of Basic Red 46 in food. The structure elucidation of this compound as well as the disadvantages of analytical methods focusing on a narrow group of targeted analytes are discussed.     

Discovery and structural elucidation of the illegal azo dye Basic Red 46 in sumac spice

An unknown red dye was discovered in a sumac spice sample during routine analysis for Sudan dyes. LC-DAD and LC-MS/MS did not reveal the identity of the red substance. Nevertheless, using LC-high-resolution MS and isotope ratio comparisons the structure was identified as Basic Red 46. The identity of the dye was further confirmed by comparison with a commercial hair-staining product and two textile dye formulations containing Basic Red 46. Analogous to the Sudan dyes, Basic Red 46 is an azo dye. However, some of the sample clean-up methodology utilised for the analysis of Sudan dyes in food prevents its successful detection. In contrast to the Sudan dyes, Basic Red 46 is a cation. Its cationic properties make it bind strongly to gel permeation columns and silica solid-phase extraction cartridges and prevent elution with standard eluents. This is the first report of Basic Red 46 in food. The structure elucidation of this compound as well as the disadvantages of analytical methods focusing on a narrow group of targeted analytes are discussed.     

Analysis of water-soluble azo dyes in soft drinks by high resolution UPLC-MS

An UPLC-Orbitrap MS system was exploited to develop and validate a method for the simultaneous determination of 11 water-soluble azo dyes (Acid Yellow 17, Acid Red 14, Acid Red 26, Acid Red 73, Acid Orange 52, Acid Orange 7, Acid Orange 12, Acid Yellow 36, Acid Orange 5, Acid Red 88 and Acid Red 9) in soft drinks. Three pairs of isomers and four disulphonated azo dyes were among a total of 11 water-soluble azo dyes obtained and purified using an SPE cartridge. They were well separated using optimized UPLC conditions with a RP18 column and a MS detector with a compatible mobile phase system. All these dyes were detected by the Orbitrap XL mass spectrometer in negative ion mode. HCD tandem MS fragment ions are first reported in this paper, and these fragment ions can be used for identification of isomers of azo dyes. According to SANCO/10684/2009, one quasi-molecular ion in full scan mode as quantification ion and one or two HCD tandem MS fragment ions as identification ions are required for compound confirmation. Matrix-matched calibration was employed for quantification. The linear matrix-matched calibration for the 11 dyes was in the range 5-200?ng?g(-1) with correlation coefficients (r) of 0.9939-0.9988. Recoveries were 68.9-110.8% with coefficients of variation of 0.9-12.0%. Depending on the dye and matrix involved, the LODs were between 1.0 and 3.2?ng?g(-1) and LOQs were between 5.2 and 9.8?ng?g(-1).     

分散染料在棉涤交织物中的扩散转移机制

为了解分散染料在棉涤交织物上的转移机理,使用蒽醌型分散红60和偶氮型分散红167对棉涤交织物进行染色,通过N,N-二甲基甲酰胺(DMF)萃取织物上的分散染料,测定分散染料DMF溶液的紫外-可见吸收光谱,计算染料的转移率和损失率.采用超景深三维显微镜分析染料在棉涤交织物中的转移机制,发现棉涤交织物浸轧染液烘干后,分散染料...     

Confirmation of non-permitted dyes detected in Akasu (red vinegar) by LC/MS

Suitable liquid chromatography/mass spetrometry (LC/MS) conditions were examined for Amaranth, Red 2G (R2G), Azo Rubine (Azo), Fast Red E (FRE) and Brilliant Blue FCF, which were detected in Akasu, a red vinegar made in Hong Kong from sake lees, on both thin layer chromatography (TLC) and photodiode array high-performance liquid chromatography (PDA-HPLC). Molecular-related ions for each dye were detected with excellent sensitivity by LC/MS using electro-spray ionization with negative ion mode, capillary voltage 3.00 kV, cone voltage 50 V and desolvation temperature 400 degrees C. LC/MS analysis of refined Akasu under these conditions enabled us to obtain clear mass spectra of R2G, Azo and FRE, which were present at trace levels in the Akasu. The results were consistent with those from TLC and PDA-HPLC. These experiments suggested that LC/MS analysis is applicable for confirmation of dyes in food.     

Determination of Sudan I and a newly synthesized Sudan III positional isomer in the color additive D&C Red No. 17 using high-performance liquid chromatography

ABSTRACT

Specifications in the Code of Federal Regulations for the color additive D&C Red No. 17 (Colour Index 26100) limit the levels of two subsidiary colors, 1-(phenylazo)-2-naphthol (Sudan I) and 1-[[2-(phenylazo)phenyl]azo]-2-naphthalenol (Sudan III o-isomer), to 3% and 2%, respectively. The present work reports the development of a high-performance liquid chromatography (HPLC) method for the quantitative determination of these subsidiary colors. Since Sudan III o-isomer needed to be synthesized for use as a reference material, a two-step procedure was devised: (i) preparative-scale synthesis of the intermediate 2-aminoazobenzene (2AAB) and its purification by counter-current chromatography and (ii) diazotization of 2AAB and coupling with 2-naphthol. Characterization of the newly synthesized Sudan III o-isomer is also reported. Sudan I and Sudan III o-isomer were quantified by using five-point calibration curves with data points ranging from 0.108 to 3.240% and 0.077 to 2.227% by weight, respectively. The HPLC method is rapid (14 min for the total analysis cycle) and simple to implement. It was applied to the analysis of test portions from 25 batches of D&C Red No. 17 submitted to the U.S. Food and Drug Administration (USFDA) for certification, and it has recently been implemented by USFDA for routine batch certification of that color additive.     

Structural determination of subsidiary colors in commercial Food Green No. 3 (fast green FCF, FD & C Green No. 3).

HPLC analysis revealed that eight subsidiary colors existed in commercial Food Green No. 3 (fast green FCF, FD & C Green No. 3). Among them, four subsidiary colors C, F, G, and H were isolated by using preparative HPLC and their structures were determined by MS and NMR. They were the disodium salt of 2-[[4-[N-ethyl-N-(3- sulfophenylmethyl)amino]phenyl][4-[N-ethyl-N-(4- sulfophenylmethyl)amino]phenyl]methylio]-4-hydroxybenzenesulfonic acid (abbreviated as m,p-G-3), the sodium salt of 2-[[(4-N-ethylamino)phenyl][4-[N-ethyl-N-(3- sulfophenylmethyl)amino]-phenyl]methylio]-4-hydroxybenzenesulfonic acid [abbreviated as HSBA-(EA) (m-EBASA)], the sodium salt of 2-[[(4-N-diethylamino)phenyl][4-[N-ethyl-N-(3- sulfophenylmethyl)amino]phenyl]-methylio]-4-hydroxybenzenesulfonic acid [abbreviated as HSBA-(di-EA) (m-EBASA)], and the sodium salt of 2-[[4-[N-ethyl-N-(phenylmethyl)amino]phenyl][4-[N-ethyl-N-(3- sulfophenylmethyl)-amino]phenyl]methylio]-4-hydroxybenzenesulfonic acid [abbreviated as HSBA-(EBA)(m-EBASA)], respectively. HSBA-(di-EA) (m-EBASA) was a subsidiary color newly found in commercial Food Green No. 3.     

Photoelectrocatalytic degradation of triazine-containing azo dyes at gamma-Bi2MoO6 film electrode under visible light irradiation (lamda > 420 nm)

Triazine-containing azo dyes, anionic reactive brilliant red K-2G, reactive brilliant Red X-3B, and reactive yellow KD-3G were degraded in the electrooxidation, photocatalysis and combined electrooxidation and phtocatalysis process at the gamma-Bi2MoO6 film electrode under visible light irradiation. Furthermore, in the combined process, synergetic degradation of the dyes was observed by the analysis of degradation kinetics and total organic carbon variation. The synergetic mechanism was studied using X-ray photoelectron spectra and electrochemical impedance spectra as well as analysis of variation of current vs time in various processes. It is suggested that application of bias potential with a lower value than the redox potential of the targeted dyes efficiently increases the photocatalysis rate of the dyes by prohibiting recombination of electrons and holes. At the bias greater than the redox potential of the dyes, the degradation of the dyes was efficiently improved bythe combined electrooxidation and photocatalysis process. The main active oxygen species involved in the dyes degradation was hydroxyl radicals as confirmed via DMPO spin-trapping electron spin resonance measurements and the effect of radical scavengers. Intermediates mainly including organic aromatic and aliphatic carboxylic acids were detected.     

Structural analysis of unknown dyes detected in hajikami (ginger pickled in vinegar)

Hajikami (ginger pickled in vinegar) is often used as a relish for grilled fish, and it often contains coloring agents. We detected Rose Bengal (R105) and two unknown dyes in some Hajikami by thin layer chromatography. In this study, we tried to characterize these unknown dyes by HPLC with photodiode array detection (PDA-HPLC), liquid chromatography/mass spectrometry (LC/MS) and nuclear magnetic resonance (NMR). PDA-HPLC analysis showed that the spectra of the unknown dyes resembled that of R105, suggesting the molecular structures of these two dyes are similar to that of R105. Furthermore, LC/MS analysis suggested that the these dyes are R105 in which one or two iodines are replaced by hydrogen. Finally, the two dyes were determined by 1H-NMR and 13C-NMR to be 4,5,6,7-tetrachloro-3',6'-dihydroxy-2',7'-diiodo spiro[isobenzofuran- 1 (3H),9'-[9H]xanthen]-3-one disodium salt and 4,5,6,7-tetrachloro-3',6'-dihydroxy-2',7'-diiodo spiro[isobenzofuran-1(3H),9'[9H]xanthen]-3-one disodium salt.     

Structural determination of the subsidiary colors in food blue No. 1 (brilliant blue FCF) aluminum lake detected by paper chromatography

One of eight Food Blue No. 1 aluminum lakes (B-1Als) used in the official inspection of coal-tar colors in fiscal year 1999 had a violet sub-spot during paper chromatography and was rejected. To clarify the orgin of the sub-spot, the violet subsidiary color (Sub-V) was isolated from the sample. On the basis of NMR and MS analyses and ion chromatography, the structure of the subsidiary color was elucidated to be 2-[[4-[N-ethyl-N-(3- sulfophenylmethyl)amino]phenyl][4-hydroxyphenyl]methylio]benzenesulfonic acid. The relative content of Sub-V to that of m,m-B-1 in the rejected sample was determined to be 39.5% by HPLC. The relative contents in other submitted samples of B-1Al were in the range of 1.1-3.6%.     

泡沫技术染深色的可行性及其应用

为了探讨泡沫染色对棉织物染深色的可行性,研究了活性艳红KE-3B在棉织物泡沫染色中的提升力和染色性能;为了推广泡沫染色在纺织加工中的应用,研究了不同类型活性染料在对棉织物的泡沫染色浅、深色工艺中的固色速率和织物K/S值与固色时间的关系。研究结果表明：活性红KE-3B在泡沫染色中具有良好的提升力,经不同质量浓度泡沫染色的织物匀染性好。在4种不同类型的活性染料泡沫染色中,染料的固色率均能达到70%~90%,KN型活性染料固色率最高,固色速率顺序为活性黑KN-B>活性大红K-2G>活性艳红KE-3B>活性艳红X-3B。     

尼龙56/羊毛混合纤维的染色同色性

采用天龙系列酸性染料对尼龙56/羊毛混合纤维进行一浴一步法染色,通过加入合适的缓染剂,考察染液pH、染色时间、染色温度等因素的影响,优化了染色工艺条件.染色结果表明:在染料质量分数为1％(omf),染液pH为4,染色时间60 min(天龙红A2R、天龙蓝A2R)或100 min(天龙黄A2R),染色温度为98℃时,天龙...     

分散染料粒径对细旦织物染色性能的影响

本文着重研究了偶氮类分散红Ｓ－５ＢＬ和蒽醌类分散艳蓝Ｅ－４Ｒ两种不同结构的染料粒径大小与细旦涤纶织物染色性能的关系，试验表明，不同粒径的染料在细旦涤纶织物上的染色性能有一定的差异，粒径较细的当杰具有较好的高温分散性，移染性，匀染性，提升力和染料利用率，但最终上染率比较低，而对颜色特性和染色牢度均无影响，这为细旦涤纶织物的染色工艺和染料的商品化加工提供了一定的参考价值，具有较好的实用意义。     

聚甲醛纤维的染色性能

采用分散蓝2BLN、分散大红3B和分散黄棕S-2RFL染料对聚甲醛(POM)纤维进行染色.考察了染色温度和染色时间对染料上染率和纤维透染性的影响.结果表明,三只分散染料对POM纤维的上染性能相似,其上染平衡温度分别为100℃、110℃和110℃.分散蓝2BLN的最大上染率较低,为80％左右;分散大红3B和分散黄棕S-2RFL的最高上染率均可达90％以上.POM纤维在110℃上染30 min后,无白芯,纤维被透染.     

双卤代均三嗪活性染料及其水解产物的 HPLC 分离方法的建立

为了研究双卤代均三嗪活性染料的水解反应,首先采用反相离子对高效液相色谱对双卤代均三嗪活性染料及其水解产物进行了色谱分离。从双卤代均三嗪活性染料的选择、色谱柱的选择、流动相的选择和优化、柱温的确定等方面,探讨了对称结构双卤代均三嗪活性染料及其水解产物的HPLC分离方法的建立过程,利用该方法对双一氟均三嗪活性染料活性红LS-2G及双一氯均三嗪活性染料活性红KE-3B的水解产物进行了分离,得到了较好的分离效果。     

Studies on melanoidin-type colorants generated from the Maillard reaction of protein-bound lysine and furan-2-carboxaldehyde – chemical characterisation of a red coloured domaine

 The identification of a coloured substructure of melanoidin-type colorants is reported in the present paper. Brown-orange melanoidins with mass >10000 daltons were isolated from a thermally treated aqueous solution of casein and furan-2-carboxaldehyde using ultracentrifugation. After complete enzymatic digestion of the protein skeleton, two intense red coloured compounds were detected in the melanoidin hydrolysate by HPLC. These compounds were identified as the previously unknown chromophoric amino acid (S)-2-amino-6-{4-[(E)-1-formyl-2-(2-furyl)ethenyl]-5-(2-furyl)-2-[(E)-(2-furyl) methylidene]-2,3-dihydro-3-oxo-1H-pyrrol-1-yl}hexanoic acid and its 2-[(Z)-(2-furyl)methylidene] isomer, by using several NMR techniques, by MS, UV, and IR spectroscopy. The identification of these novel compounds verifies the idea that melanoidin-type colorants can be generated by a cross-linking reaction between a low molecular weight chromophore and a non-coloured high molecular weight biopolymer. Received: 19 August 1997 / Revised version: 24 October 1997     

Studies on melanoidin-type colorants generated from the Maillard reaction of protein-bound lysine and furan-2-carboxaldehyde – chemical characterisation of a red coloured domaine

 The identification of a coloured substructure of melanoidin-type colorants is reported in the present paper. Brown-orange melanoidins with mass >10000 daltons were isolated from a thermally treated aqueous solution of casein and furan-2-carboxaldehyde using ultracentrifugation. After complete enzymatic digestion of the protein skeleton, two intense red coloured compounds were detected in the melanoidin hydrolysate by HPLC. These compounds were identified as the previously unknown chromophoric amino acid (S)-2-amino-6-{4-[(E)-1-formyl-2-(2-furyl)ethenyl]-5-(2-furyl)-2-[(E)-(2-furyl) methylidene]-2,3-dihydro-3-oxo-1H-pyrrol-1-yl}hexanoic acid and its 2-[(Z)-(2-furyl)methylidene] isomer, by using several NMR techniques, by MS, UV, and IR spectroscopy. The identification of these novel compounds verifies the idea that melanoidin-type colorants can be generated by a cross-linking reaction between a low molecular weight chromophore and a non-coloured high molecular weight biopolymer. Received: 19 August 1997 / Revised version: 24 October 1997     

超声波对普拉红B染料缔合状态的影响

 染料在溶液中的缔合状态对染色有着重要影响。本文通过染液的电导率和吸收光谱变化研究了超声波对染料缔合状态的影响。结果表明,弱酸性普拉红B溶液的最大吸收波长随着浓度的增加逐渐减小,发生蓝移,其缔合浓度为1×10-5mol/L。在高于染料缔合浓度的条件下,随着温度的升高,经超声波处理的染液电导率的增加幅度大于未经超声波处理的。在50℃下,染液随超声波处理时间的延长,其电导率逐渐增加,吸收光谱发生红移,吸收光谱中肩峰的峰值逐渐减小。     

Activated carbon as an electron acceptor and redox mediator during the anaerobic biotransformation of azo dyes

Activated carbon (AC) has a long history of applications in environmental technology as an adsorbent of pollutants for the purification of drinking waters and wastewaters. Here we describe novel role of AC as redox mediator in accelerating the reductive transformation of pollutants as well as a terminal electron acceptor in the biological oxidation of an organic substrate. This study explores the use of AC as an immobilized redox mediator for the reduction of a recalcitrant azo dye (hydrolyzed Reactive Red 2) in laboratory-scale anaerobic bioreactors, using volatile fatty acids as electron donor. The incorporation of AC in the sludge bed greatly improved dye removal and formation of aniline, a dye reduction product. These results indicate that AC acts as a redox mediator. In supporting batch experiments, bacteria were shown to oxidize acetate at the expense of reducing AC. Furthermore, AC greatly accelerated the chemical reduction of an azo dye by sulfide. The results taken as a whole clearly suggest that AC accepts electrons from the microbial oxidation of organic acids and transfers the electrons to azo dyes, accelerating their reduction. A possible role of quinone surface groups in the catalysis is discussed.     

聚乳酸纱线色牢度测试及其染色工艺

 在不同实验条件下,采用17种不同结构的分散染料对聚乳酸纱线染色。结果表明,分散红玉R167、分散橙O30、分散蓝284可作为聚乳酸染色中的三原色染料。分析17种染料结构发现,单偶氮且具有醋酸酯基的分散染料对聚乳酸纤维有较高的上染率。对染色工艺进行优化研究表明：当pH=4～5,温度11O℃,保温时间30～40 min染色条件下,聚乳酸纱线能获得高质量的染色效果,还原清洗条件中净洗剂FB的加入能提高染色纱线的耐汗渍色牢度及耐洗色牢度1～1.5级。