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The volatile components of 10 agarwood samples from 5 countries (Kalimantan, Malaysia, Bangladesh, India, Indonesia) were analyzed by headspace gas chromatography-mass spectrometry (HS-GC-MS). The results showed that the volatile components of 10 agarwood samples were mainly aromatic and sesquiterpe-noids. The types and relative contents of volatile components of agarwood samples with the same origin but different morphology were different. The volatile components of the samples also showed certain differences. The mannene and (+) -cyclodecene were only detected in the agarwood samples of Malaysia and could be used as the characteristic components of the agarwood in the producing area; a-cluene and β-Guaiacrox were only detected in Indonesian agarwood samples and could be used as the characteristic component of the agarwood in this area; (+)-α-long-leafene and a-carboene were only detected in Indian agarwood samples and could be used as the characteristic component of agarwood in this area; the types and contents of alcohols in agarwood samples from Indonesia were significantly lower than those in other places. The results could provide a new idea for the rapid detection and identification of the agarwood production area. [ABSTRACT FROM AUTHOR]

Using electrospray ionization-high resolution mass spectrometry (ESI-HRMS) method to confirm the catalpol propionylated products,and using peak area normalizing method to complete the semi quantitative,the analysis method on the synthesize process of catalpol propionylated products was established. The results showed that the ESI-HRMS method could quickly determine the type of propionylated products; the peak area normalization method could calculate the relative content of each catalpol propionylated products, which could be controlled to synthesize the main or mixed products with the specific structure by controlling the reaction conditions according to the need. The application of ESI-HRMS method in the reaction process of catalpol pro-panolation could provide a new approach for the analysis of the synthesis process of catalpol propanylated products. [ABSTRACT FROM AUTHOR]

Hundreds of endogenous peptides were released from milk proteins within the human mammary gland and some of them possess a variety of bioactive functions. Thus, it is important to investigate human milk endogenous peptides for infant health. Peptidomics based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) has been used to investigate human milk endogenous peptides. Extraction of endogenous peptides from human milk is an essential and key procedure for analyzing human milk peptides using LC-MS/MS. This study aimed to compare methods for extracting endogenous peptides from human milk using LC-MS/MS. Ultrafiltration methods including that not involving denaturation (UF 1), that involving heat denaturation (UF 2), and that involving chemical denaturation (UF 3), precipitation methods using trichloroacetic acid (PCPN 1) and alcohol (PCPN 2), and an enrichment method using highly ordered mesoporous carbon (OMC) were used to extract endogenous peptides from human milk. Extracted endogenous peptides were then analyzed using LC-MS/MS. The samples extracted using UF 1 and UF 2 comprised 1161±8 and 1017±91 endogenous peptides, respectively. More than 70% peptide sequences in each sample extracted using UF 1 and UF 2 overlapped. The results revealed that endogenous peptides extracted using UF 1 and UF 2 showed similar characteristics. UF 1 yielded the highest number of peptides, whereas UF 3 extracted the least number of peptides at 366±18. The number of endogenous peptides extracted using PCPN 1 and PCPN 2 were 779±69 and 876±55, respectively. However, their characteristics were quite different, and only about 50% peptide sequences overlapped. The number of peptides extracted using OMC (549±151) was not remarkable compared with that using other methods. However, the isoelectric point (pI) and grand average of hydropathicity (GRAVY) of the peptides extracted using OMC were different from those extracted using other methods. This method presented no selectivity for the endogenous peptides with different pI and GRAVY and may be used to extract unique peptides from human milk. A total of 205 peptides were commonly identified in the samples using each of the six methods. The percent of shared peptides across the six samples ranged from 13% to 23%. The number of unique peptides in the samples extracted using UF 1 and UF 2 (226 and 228, respectively) were the highest among those extracted using the six methods. The results showed that all six methods could be used to extract endogenous peptides from these high-abundance precursor proteins. A total of 21, 38, and 19 peptides were extracted from lactotransferrin using UF 2, UF 3, and OMC, respectively, and the coverage rates of these peptides in lactotransferrin were 14%, 16%, and 19%, respectively. These three methods could extract the endogenous peptides from lactotransferrin in human milk, but PCPN 1 that has been commonly used in previous studies could not. The peptides from β -casein, polymeric immunoglobulin receptor, osteopontia, α S1 -casein, κ -casein, and bile salt-activated lipase were identified in all samples extracted using the six methods. Moreover, these precursor proteins contributed 88% peptides in the samples extracted using the six methods. In conclusion, UF 1 and UF 2 were efficient procedures for extracting endogenous peptides from human milk. In addition, UF 2 could extract peptides from lactotransferrin, which is the optimum choice for extracting endogenous peptides from human milk. Additionally, the OMC enrichment method can be used to enrich and extract specific endogenous peptides from human milk. This study systematically compared the sample preparation methods commonly used in human milk endogenous peptidomics in recent years. The results provide strong support for uniform and standardized sample preparation methods. An ultrafiltration method without denaturation, which is more advantageous than the currently commonly used trichloroacetic acid precipitation method, was also established to prepare human milk endogenous peptide samples. In combination with OMC, this method can help in a more comprehensive and in-depth understanding of the endogenous peptidome of human milk.

A polyaniline/graphene (PANI/G) composite was selected as the coating material to prepare a coated anion-exchange chromatographic stationary phase. First, aniline and graphene were used to prepare the PANI/G composite, which was coated onto the surface of poly(styrene-divinylbenzene) (PS-DVB) microspheres by physical absorption. Then, a series of anion-exchange stationary phases with different exchange capacities were obtained by quaternization using the nitrogen atom of polyaniline as the reactive site. The stationary phase was characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), and elemental analysis (EA). The results revealed that PANI/G was successfully coated onto the surface of PS-DVB and quaternized. The efficiency of the self-fabricated chromatographic column was evaluated by separating conventional anions and organic acids. The PANI/G-coated PS-DVB anion-exchange chromatographic column that was quaternized eight times showed good separation performance for conventional anions and organic acids.

Human milk is the optimal food for infant nutrition and growth. Proteins are abundant and represent a key element in human milk. With recent developments in proteomics, more tools are available to explore human milk proteins. This article aims to review the recent investigations of human milk proteins using proteomic methodologies. This review focuses on using proteomics as a tool to study the components of human milk proteins; dynamics of human milk proteins during lactation; comparison of proteome from human milk and other source milk, phosphoprotein and glycoprotein analysis of human milk; endogenous peptides in human milk; and the human milk proteome and its correlation to curing of various diseases. Proteomics technology has enabled the study of human milk proteins in the era of micronutrient research, and the results of these studies will be helpful for further analysis of mother and infant health.

Allyl glycidyl ether (AGE) was selected as the copolymerization monomer to prepare a copolymer latex-agglomerated anion exchange chromatography stationary phase for ion chromatography (IC). First, allyl glycidyl ether-styrene (AGE-ST) copolymer latex was prepared by the saponification emulsion polymerization method. It was then quaternized by reacting alternatively with methylamine (MA) and 1,4-butanedioldiglycidyl ether (BDDGE) and agglomerated on the surface of sulfonated polystyrene-divinylbenzene (PS-DVB) microspheres to obtain a copolymer latex-agglomerated anion exchange chromatography stationary phase. The stationary phase was characterized by scanning electron microscopy (SEM), FT-IR and elemental analysis (EA). It was found that the diameters of the PS-DVB microsphere and AGE-ST copolymer latex were about 6 μm and 300 nm, respectively. The quaternized AGE-ST copolymer latex was successfully agglomerated on the surface of PS-DVB microspheres and the nitrogen content increased as quaternization time was increased. The chromatographic properties were evaluated by separating conventional anions and organic acids. The results showed that the quaternized AGE-ST copolymer latex-agglomerated PS-DVB anion exchange column exhibited good separation properties toward anions. Therefore, based on the good pH toleration and reaction activity of the newly developed stationary phase, it was concluded that using AGE as a monomer was a good choice.