高效液相色谱法测定化妆品中依克多因的含量

建立高效液相色谱法测定化妆品中依克多因的分析方法,采用Agilent Poroshell 120 EC-C₁₈色谱柱（100 mm×3.0 mm,2.7μm）分离,以甲醇和p H为3.0的40 mmol/L磷酸二氢钠-10 mmol/L 1-庚烷磺酸钠缓冲溶液梯度洗脱,流速0.8 m L/min,柱温30℃,检测波长210 nm。采用外标法定量测定化妆品中的依克多因含量。结果表明,依克多因在5～800 mg/L的质量浓度范围内呈现良好线性关系,相关系数为0.999 8,方法的检出限和定量限分别为0.3和1.0 mg/L。该方法具有分离效率高、分析时间短、节省溶剂等优点,解决了依克多因在C₁₈色谱柱上保留弱的问题。     

Biogenic amines assessment during different stages of the canning process of skipjack tuna (Katsuwonus pelamis)

The present research focused on the biogenic amines (BAs) formation in skipjack tuna (Katsuwonus pelamis) throughout the whole canning process. In agreement with its wide employment on this species, on‐board brine immersion freezing (BIF) was tested as post‐mortem processing. The study included fish samples corresponding to different stages of the canning process such as frozen, thawed, cooked and canned; after cooking, two kinds of tuna muscles were considered, that is, whole fillets (main product) and grated muscle (off‐product arising from small pieces). For the BAs (tryptamine, putrescine, cadaverine, histamine, spermidine and spermine) assessment, an HPLC‐DAD method was developed and validated in skipjack tuna samples, in agreement with different parameters such as suitability, linearity, limits of detection and quantification, precision, accuracy and robustness. Tuna submitted on‐board to BIF procedure provided low levels of spermine and spermidine (up to 27.6 mg kg^?1), while contents on the remaining BAs maintained below the limit of detection. Throughout the different stages of the canning process, skipjack tuna showed a low formation of most BAs; interestingly, histamine content was found below 10.6 mg kg^?1 level. The highest values were obtained for spermidine, these related to cooked grated tuna (from 22.6 to 66.7 mg kg^?1) and canned grated tuna (from 70.6 to 104.4 mg kg^?1). Values for pH assessment in all kinds of tuna samples corroborated the results obtained for BAs determination. BIF procedure proved to be an amenable post‐mortem processing to guarantee the quality of canned skipjack tuna.     

Detection and analysis of triterpenic compounds in apple extracts

A new technique for the rapid detection and analysis of triterpenic compounds in apple extracts using HPLC was developed and validated. The main advantage of this technique is the short duration of the analysis – this makes this technique superior to others currently applied for the routine HPLC analysis of triterpenic compounds. The developed, optimized, and validated technique was used for the evaluation of triterpenic compounds in samples of different cultivars of apples, their peels, and flesh. In total, four triterpenic compounds were isolated and identified. Ursolic acid was the dominant compound in all the tested apple samples. The highest amounts of triterpenic compounds were detected in the peels of the ‘Lodel’ apple cultivar, and thus apples of this cultivar may be potentially useful for the isolation of individual compounds and the production of functional food and dietary supplements.     

GC和HPLC分析金银花多糖的单糖组成方法比较

目的:GC法和HPLC法分析金银花多糖的单糖组成,并对两种方法进行比较。方法:金银花多糖经2.0 mol·L-1的三氟乙酸水解后,用糖腈乙酸酯衍生化-GC法和1-苯基-3-甲基-5-吡唑啉酮(PMP)柱前衍生化-HPLC法分别测定其单糖组成及其比例。结果:GC法检测出金银花多糖由鼠李糖(L-Rha)、阿拉伯糖(D-Ara)、甘露糖(D-Man)、木糖(D-Xyl)、葡萄糖(D-Glc)、半乳糖(D-Gal)组成;HPLC法检测到金银花多糖中含有甘露糖(D-Man)、鼠李糖(L-Rha)、葡萄糖醛酸(D-GlcA)、葡萄糖(D-Glc)、半乳糖(D-Gal)、阿拉伯糖(D-Ara)和木糖(D-Xyl),其中半乳糖(D-Gal)与阿拉伯糖(D-Ara)的色谱峰重叠。结论:两种方法均能检测出中性糖,HPLC法不仅能测中性糖,还能检测出葡萄糖醛酸,对金银花多糖的单糖组成分析GC与HPLC联合使用较为合适。     

液态发酵红曲黄色素粗提物色素组分的分离纯化与鉴定

采用高效液相色谱、质谱和核磁共振分析,对液态发酵红曲黄色素粗提物色素组分进行分离纯化和分子结构鉴定,确定其化学结构式。结果表明,红曲黄色素有2种主要色素成分,组分A和组分B,两者在分析型液相色谱上分离度达到2.51。进一步将分析型液相分离条件在制备型液相上进行放大并调整,收集得到组分A和组分B,纯度分别为98.95%和99.02%,达到标准品的纯度。通过质谱分析结合一维及二维核磁共振,确定组分A的相对分子质量为358,为红曲素(C21H26O5),组分B的相对分子质量为332,为Monaphilone B(C20H28O4),A和B的显色性能来自于其分子结构中的α,β-不饱和酮结构。     

Influence of temperature and environmental conditions on aflatoxin contamination in maize collected from different regions of Pakistan during 2016–2019

Aspergillus and their associated metabolites like aflatoxins (AFs) are one of the extremely significant contaminants that affect food production around the world. This species decreases yield and grains quality under suitable environmental conditions. AFs were identified in various food commodities, have been recognized as carcinogenic, mutagenic, teratogenic and immunosuppressive. From 2016 to 2019, a total of 324 samples of maize were obtained from diverse areas of Pakistan and examined for AFs level. AFs were determined using an HPLC validated method through post-column derivatization and fluorescence detection. This study also focused on the effect of climatic conditions on AF production. The total AFs (B₁+B₂+G₁+G₂) were detected in 267 (82.4%) samples, ranged between 0.69 and 356.7 μg/kg with a mean of 15.27 ± 0.82 μg/kg. A total of 182 (56.2%) and 85 (26.2%) samples had AFs level above the maximum acceptable limit as accepted by European Union (EU) and United States of America (USA), respectively. The outcomes of the existing study indicated that the climatic situations in the examined areas had a great impact on AFs contamination. Significant differences were found between AFs contamination levels in the samples collected in different months (p < 0.05). The most contaminated samples were identified in July, August and September as the climatic conditions favored the AF production. These outcomes suggested that the food commodities must be regularly examined in order to prevent the health of human and animal from the hazardous effects produced by AFs contamination.     

红曲改善客家黄酒的品质

本研究采用HPLC法研究不同酒曲配方对酿造客家黄酒时产生的风味物质有机酸的影响,考察红曲对黄酒发酵过程中有机酸风味、总量的影响。发酵30d时三种酒样的有机酸总量差异明显,采用酒药、麦曲酿制的黄酒(酒样Ⅱ)最高,单用红曲(酒样Ⅲ)次之,红曲、酒药、麦曲复配(酒样Ⅰ)最少,分别为33.83 g/L、27.72 g/L和22.67 g/L。其中,Ⅰ、Ⅱ、Ⅲ号酒样中挥发性酸与非挥发性酸的比例分别为1:4、1:1和2:1;酒样中乳酸含量差异较大,Ⅰ号酒样最高,为11.40 g/L,Ⅲ号酒样最少,为6.02 g/L;乙酸含量在三种酒中较接近,约5.5 g/L;Ⅰ、Ⅱ号酒样中琥珀酸含量较接近约为5 g/L;丙酸在Ⅱ、Ⅲ号酒样中含量大,但在Ⅰ号酒样中未检出。另外,Ⅰ号酒样中还测出少量的苹果酸和柠檬酸。结果表明,在客家黄酒酿造时添加适量红曲,有助于维持客家黄酒的酸味平衡,提升味觉层次感。     

高效液相色谱法测定肉桂醛生物转化体系中10种苯基香料

建立一种同时测定微生物转化肉桂醛体系中10种天然苯基香精香料(苯甲醇、苯甲醛、苯甲酸、苯乙醇、苯乙酮、肉桂醇、肉桂醛、肉桂酸、3-苯丙醇和3-苯丙醛)的高效液相色谱分析方法。试样经无水乙醇提取,离心,过滤后进样。色谱分析采用SunFireTMC18色谱柱(250 mm×4.6 mm,5μm),以甲醇∶乙腈∶水∶冰醋酸=28.4∶18∶53.6∶0.04(体积比)为流动相,流速1.0 mL/min,紫外检测器检测。10种待测物在2.00 mg/L^318.60 mg/L范围内线性关系良好(0.9987≤R2≤0.9996),方法检出限(method detection limit,LOD,S/N=3)为0.36 mg/L^1.16 mg/L,在低、中、高3个加标水平下的平均回收率为92.13%~102.90%,RSD为0.62%~4.01%。该方法可用于微生物转化肉桂醛合成天然苯基香料的生物反应体系的成分分析,也可用于生物转化肉桂醛合成天然香料的菌种选育工作中。