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Quantitative analysis of cow whole milk and whey powder adulteration percentage in goat and sheep milk products by isotopic dilution-ultra-high performance liquid chromatography-tandem mass spectrometry

文献作者：Xing Ke, Jingshun Zhang, Shiyun Lai, Qi Chen, Yu Zhang, Yirong Jiang, Weimin Mo, Yiping Ren   《Analytical and Bioanalytical Chemistry》

ABSTRACTS
The aim of the study was to develop a method for quantification of cow’s whey and whole milk powder in goat or sheep milk products including infant formula. A ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was established for simultaneous quantification of four caseins and two major whey proteins by detecting their signature peptides, which were able to act as markers for differentiating goat or sheep from cow whey and whole milk powder in infant formulas. The signature peptides were screened based on the computational prediction by Biolynx software, and confirmed by database searching after analysis of liquid chromatography-quadrupole-time-of-flight tandem mass spectrometry (LC-Q-TOF-MS). The isotopic-labeled signature peptide was used as internal standard to compensate the matrix effect. The limits of quantification were 0.01–0.05 g/100 g for target proteins. The observed recovery rates ranged from 82.3 to 116.6 % and the reproducibility was excellent (RSD <12 %) at different spiking levels. The RSDs of intra- and inter-day precision were 2.8–6.2 and 3.3–9.8 %, respectively. The multiple reaction monitoring method was successfully applied to milk powder with different composition, showing high specificity and accuracy in detection of species involved. The calculating formula was designed to assess the composition of adulteration in the actual detection of infant formulas. These results highlight applicability of this method for the detection of infant formulas with complicated matrix.
KEY WORDS
Adulteration ;Quantification ;Goat and sheep; Infant formula .
SCREENSHOT

RELATED PRODUCTS
The selective signature peptides and their stable isotope-labeled signature peptides of α-lactalbumin, β-lactoglobulin, β-casein, α s1 -casein, α s2 -casein, and κ-casein (Table 1) were synthesized by ChinaPeptides Co., Ltd. (Shanghai, China).
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https://link.springer.com/article/10.1007/s00216-016-9987-9
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CAS:85466-18-8|Thymopoietin II (32-35)|RKDV

Contact： Liven Qian(钱叶华)-Custom Peptide Mobile: 13761298676（微信） Email：cps037@chinapeptides.net QQ：2880526724 ChinaPeptides Co., Ltd./强耀生物科技有限公司 Name Thymopoietin II (32-35) Code [85466-18-8] The alias Thymopoietin II (32-35) Sequence (single letter abbreviation) RKDV Sequence (three-letter abbreviation) H-Arg-Lys-Asp-Val-OH (trifluoroacetate salt) A basic description TP-4 and TP-3; shortest active thymopoietin II fragments described that exhibit potent immunoregulatory properties in vitro and in vivo. solubility The molecular weight 516.6 Chemical formula C21H40N8O7 The purity 80%，90%，95%，98%，99% Weight 1mg,5mg,10mg,50mg,100mg,1g Storage conditions Store at -20°C. Keep tightly closed. Store in a cool dry place. Number of Residues: 4 1-Letter Code: RKDV 3-Letter Code: Arg-Lys-Asp-Val Molecular weight (Mr): 516.6 g/mol Isoelectric point: 10.1 Net charge at pH 7.0: 1.0 Average hydrophilicity: 1.9 Ratio of hydrophilic residues / total number of residues...
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