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Creative use of 3D printing to create analytical standards greatly increased the sample homogeneity and the accuracy of the desired concentration.

This study investigated the effect of storage time on biochemical characteristics of hawk tea (Litsea coreana) and explored the correlation between the content of flavonoids and polyphenols and antioxidant activity. The antioxidant activity and the content of inclusions, amino acid, and mineral elements in hawk tea processed by boiling water fixation and packed in airtight polypropylene bags and stored in 0°C refrigerator under different storage time (one year, three years, and six years) were analyzed. Results indicated that the biochemical characteristics of hawk tea changed less within 12 months. The total content and types of amino acids in hawk tea reached the maximum in the third year, as well as the content of total trace elements. The water extracts, tea polyphenol, caffeine, lysine, valine, isoleucine, glycine, proline, Ca, and Zn decreased continuously in the storage period of 6 years, but the total flavonoids, Mg, and Ni changed just the opposite. Total polyphenol is the main antioxidant material in hawk tea. Results of the present study provided useful information for people to systematically understand the changes of tea in the storage process and to reasonably develop hawk tea product.

Anthocyanins have attracted great attention because of their potential therapeutic benefit. However, the effective technique for simultaneous separation and preparation multiple anthocyanin monomers with high purity and high yield is still deficient. In this study, the chromatographic conditions of HPLC were optimized to investigate six well-known major anthocyanins (delphinidin-3-O-glucoside, cyanidin-3-O-glucoside, petunidin-3-O-glucoside, pelargonidin-3-O-glucoside, peonidin-3-O-glucoside and malvidin-3-O-glucoside) in blueberry. The separation conditions were optimized in analytical HPLC and further applied in semi-preparative HPLC to prepare anthocyanin monomers. The results showed that six well-known major anthocyanins were well separated under the condition of using acetonitrile-water (contained 0.3% phosphoric acid) as a mobile phase with gradient elution at a detection wavelength of 520 nm. The method showed good linear correlations between the concentrations and peak areas of the six components with correlation coefficients greater than 0.9994, and the detection limits of the six anthocyanins were 0.010���0.035 ��g/mL, and the quantification limits were 0.033���0.117 ��g/mL, which was suitable for the determination of anthocyanins in products. In the same experimental conditions, six well-known major anthocyanins were simultaneously prepared by semi-preparative HPLC with high purity to 99% and high yield to 22.5%. This study provides a practical and valuable method for simultaneous determination and preparation of six well-known major anthocyanins.

Fixation is one of the critical steps in tea processing and can cause various physico-chemical changes, thus affecting tea quality. There are many tea processing techniques, but their influence on quality remains unclear. Here, we studied the impact of different fixation methods, including for 6 or 10 min by machine, by iron pan, or by boiling water, on the biochemical characteristics of hawk tea. The results showed that tea fixation technique had a significant influence on the sensory quality, biochemical components, and antioxidant activity of the tea. Compared to other fixation techniques, fixation by boiling water produced a more nutritious hawk tea with stronger DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging activity (EC50 = 6.56 μg/mL). Processing with boiling water also resulted in a better sensory quality with a unique sweet aftertaste. This tea also contained more polyphenols (19.60%), total amino acids (21,219 mg/100 g), essential amino acids (10,564 mg/100 g), and trace elements (5873.13 mg/kg). These results can guide the development of hawk tea products.

This study investigated the effect of storage time on biochemical characteristics of hawk tea (Litsea coreana) and explored the correlation between the content of flavonoids and polyphenols and antioxidant activity. The antioxidant activity and the content of inclusions, amino acid, and mineral elements in hawk tea processed by boiling water fixation and packed in airtight polypropylene bags and stored in 0°C refrigerator under different storage time (one year, three years, and six years) were analyzed. Results indicated that the biochemical characteristics of hawk tea changed less within 12 months. The total content and types of amino acids in hawk tea reached the maximum in the third year, as well as the content of total trace elements. The water extracts, tea polyphenol, caffeine, lysine, valine, isoleucine, glycine, proline, Ca, and Zn decreased continuously in the storage period of 6 years, but the total flavonoids, Mg, and Ni changed just the opposite. Total polyphenol is the main antioxidant material in hawk tea. Results of the present study provided useful information for people to systematically understand the changes of tea in the storage process and to reasonably develop hawk tea product., The biochemical characteristics of hawk tea processed by boiling water fixation changed less within 12 months. The total content and types of amino acids in hawk tea reached the maximum in the third year, as well as the content of total trace elements. The water extracts, tea polyphenol, caffeine, lysine, valine, isoleucine, glycine, proline, Ca, and Zn decreased continuously in the storage period of 6 years, but the total flavonoids, Mg, and Ni changed just the opposite. Total polyphenol is the main antioxidant material in hawk tea.

Liver plays a major role in metabolism and acts as a source of energy for the body by storing glycogen. Also, working with other systems and organs, it is responsible for several important functions such as storing iron, detoxifying harmful substances, maintaining the hormonal balance, and producing immune factors to fight infections. Cattle seemed to be the most sensitive animal species with respect to some metal toxicities resulting from ingestion of feed material. With the growing interest and investigation in the biological effects in recent years, it is important and necessary to develop accurate and comparable analytical methods for elements in bio-samples. It has, however, been 10 years since the tissue sample (bovine liver) of CCQM-K49 key comparison. Therefore, the IAWG has included the need for such a key comparison to maintain, expand and improve core capabilities, and to support specific CMCs claim in bio-sample analysis as well.

Liver plays a major role in metabolism and acts as a source of energy for the body by storing glycogen. With the growing interest and investigation in the biological effects in recent years, it is important and necessary to develop accurate and comparable analytical methods for elements in bio-samples. It has, however, been 10 years since the tissue sample (bovine liver) of CCQM-K49 key comparison. The purpose of CCQM-K145 is to ensure the comparable and traceable measurement results for essential and toxic elements such as P, S, Zn, Mn, Ni, Mo, Sr, Cr, Co, Pb, As and Hg in bovine liver among NMIs and other designated measurement bodies worldwide. The comparison was agreed by IAWG as 6th IAWG Benchmarking Exercise with Zn and Ni as exemplary elements at the meeting in Korea in the early October 2016. The results of CCQM-K145 are expected to cover the measurement capability and support CMCs claiming for inorganic elements in the similar biological tissue materials and food samples. 30 NMIs and DIs registered in CCQM-K145. With respect to the methodology, a variety of techniques such as IDMS, ICP-OES, ICP-MS(non-ID), AAS and NAA were adopted by the participants. For Zn, Ni, Sr, Pb and Hg measurements, most participants chose ID-ICP-MS method, which showed the better performance in terms of consistency and reliability of the measurement results. In aspect of the traceability for the measurement results in CCQM-K145, most participants used their own (in house) CRMs or other NMI's CRMs to guarantee trace to SI unit. Most participants used similar matrix CRMs for quality control or method validation. Base on different statistic way to calculate the reference mass fraction values and associated uncertainties for each measurand, removal of the suspected extreme values, and discussion at the IAWG meetings, the median values are proposed as the KCRV for Zn, Ni, Mn, Mo, Cr, Pb and Hg; the arithmetic mean values are proposed as the KCRV for P, S, Sr, Co and As. In general, the performances of the majority of CCQM-K145 participants are very good, illustrating their measurement capabilities for Zn, Ni, P, S, Mn, Mo, Sr, Cr, As, Co, Pb and Hg in a complex biological tissue matrix. Bovine liver contains many kinds of nutrients and microelements, it can be regarded as a typical representative material of biological tissue and food. In CCQM-K145, the analytes involved alkali metals and transition elements, metalloids / semi-metals and non metals with a range of mass fraction from mg/g to μg/kg. CCQM-K145 also tested the ability of NMIs/DIs to determine elements that were easy to be lost and polluted, and interfered significantly. The chemical pretreatment methods of samples used in the comparison is suitable for general food and biological matrix samples. A variety of measurement methods used in the comparison represent the main instrumental technology for elemental analysis. Therefore, for supporting CMC claim, CCQM-K145 is readily applicable to measurement of more elements in a wide range of biological materials (including liquids and solids) and meat products. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Accurate molar mass measurement of the highly 28Si-enriched crystal (AVO28) plays a crucial role in the accurate determination of the Avogadro constant and thus the new definition of the kilogram. At the National Institute of Metrology (NIM), a high resolution inductively coupled plasma mass spectrometer (HR-ICP-MS) combined with the ‘virtual element’ isotope dilution mass spectrometry (VE-IDMS) method was used to determine the molar mass of the AVO28 material. The key advantage of this approach is that it can separate interferents, such as 28Si1H, completely from silicon ions when using medium mass resolution mode (M/ΔM ∼ 5000). During the sample preparation, AVO28, WASO 04, and enriched 29Si and 30Si materials were dissolved with 25% (mass fraction) tetramethylammonium hydroxide (TMAH), and the amounts of TMAH in prepared sample solutions were finally diluted to 0.025% to maximally reduce the potential interference of nitrogen or carbon based polyatomic species on silicon isotopes. Dead time correction and mass bias correction were also studied and performed. As a result, an average molar mass of four pieces of the AVO28 material was determined to be 27.97696905 g mol−1 with an associated relative standard uncertainty of 9.4 × 10−9 (k = 1). This result is in between the reported results of the Physikalisch-Technische Bundesanstalt (PTB, Germany), the National Metrology Institute of Japan (NMIJ, Japan), the National Institute of Standards and Technology (NIST, USA) and the National Research Council (NRC, Canada), with its uncertainty level very close to that of PTB and NRC.

We have determined the absolute isotopic composition of ytterbium in six varieties of (terrestrial source) materials based on calibrated mass spectrometry using multi-collector inductively coupled plasma mass spectrometry. Instrumental mass bias was corrected by measuring a series of mixture solutions, which were gravimetrically prepared with three high purity and isotopically enriched isotopes 171Yb, 172Yb and 174Yb. The isotopic compositions of three enriched isotope materials were accurately measured by means of total evaporation thermal ionization mass spectrometry. Six natural-like ytterbium materials including NIM GBW04623 and NIST SRM3166a, yielded the absolute isotopic composition (in at%) of 168Yb 0.12648(22), 170Yb 3.0280(19), 171Yb 14.239(5), 172Yb 21.789(5), 173Yb 16.119(3), 174Yb 31.881(8), and 176Yb 12.817(12). The new atomic weight of ytterbium was calculated to be 173.0417(5) (k = 2) based on these data. In addition, an ytterbium isotopic certified reference material in nitric acid solution (GBW04623) was developed by using a metrological approach, which would be proposed as the delta zero reference for ytterbium.

A fully calibrated strategy has been investigated for the first time for the accurate determination of absolute isotopic composition and atomic weight of molybdenum using multiple-collector inductively coupled plasma mass spectrometry. The correction for instrumental mass bias was performed using synthetic isotope mixtures, which were gravimetrically prepared with all of the seven high-purity and isotopically enriched molybdenum isotope materials together. Six natural molybdenum materials, including molybdenum standard solution NIST SRM 3134, were accurately measured and yielded the absolute isotopic composition (in atom %, k = 1) of 92Mo-14.690(18), 94Mo-9.173(6), 95Mo-15.865(5), 96Mo-16.666(3), 97Mo-9.588(4), 98Mo-24.307(16), and 100Mo-9.711(13). These isotopic data enable an atomic weight Ar(Mo) of 95.9466(34) (k = 2) to be calculated, which is slightly lower than the current standard atomic weight 95.95(1) and with a much improved uncertainty. The associated uncertainties were evaluated according to t...

The amphiphilic hyperbranched polyesteramides (AHPAs) consisting of hydrophobic hyperbranched polyether cores and hydrophilic poly (ethyleneglycol) arms with urethane bonds in the molecular structure were synthesized by solution polymerization in chloroform using hexamethylene diisocyanate (HMDI) as a coupling agent. And their chemical structures were confirmed by FT-IR and and 13C NMR. Further, the AHPAs were applied to disperse organic pigments and their dispersibilities were investigated. The results showed that AHPAs had good dispersing effect on organic pigments. When the dosage of AHPA was 12% (on the weight of pigment), the dispersing effect of AHPA on phthalocyanine green was the best with the lowest relative settlement rate, viscosity and particle size. The dispersibilities of AHPA on organic pigments were phthalocyanine green > benzidine yellow G > pigment red F5R. AHPAs have the characteristics of high solubility, low viscosity, good rheological properties and no pollution and would be the ideal materials for using as the pigment dispersants.

In order to improve the stability of blueberry anthocyanins, microencapsulation of blueberry anthocyanins was investigated by spray drying method and the stability of the native and microencapsulated anthocyanins was evaluated. The optimal microencapsulation parameters were as follows: β-cyclodextrin-whey protein-arabicgum with the quality ratio of 16:8:1 as wall material, the blueberry anthocyanins as core material, core-to-wall quality ratio of 1:2.5, the emulsion concentration was 250 g/L, rotary speed 2000 r/min, emulsification time 10 min, feed flow rate 350 mL/h, inlet air temperature 160 °C, outlet air temperature 80 °C. The encapsulation efficiency of 95% was obtained under the optimized conditions. The microcapsulated blueberry anthocyanins were dark-red powder with smooth spherical shape, and were more stable than the native anthocyanins when exposed to light and temperature.

To design and prepare targeted pesticides with environmentally responsive controlled release via compound and chemical modifications has shown great potential in creating novel pesticide formulations. Biological pesticide has spurred demand for efficient and effective delivery systems. In this work, an environmentally photoresponsive controlled release pesticide film was developed by encapsulating biological pesticide with spiropyran-grafted polyacrylic acid polymer as carrier and carboxymethyl chitosan as film-forming agent. Spiropyran-grafted polyacrylic acid polymer carrier had the characteristics of pH and light response. Under the pH response, pesticides were encapsulated. And under the light response, controlled release of pesticides was realized. A series of biological pesticides were encapsulated in the photoresponsive carrier and had high encapsulation rate. The photoresponsive polymer films could therefore be considered an efficient material for application in controlled release systems in agriculture.