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Agilent 2D liquid phase platform leads the way in impurity analysis of vitamin D soft capsules
Date: 2025-10-29Read: 0
At the beginning of this year, the National Health Commission released the "2024 Report on the Nutrition and Chronic Disease Status of Chinese Residents", once again pushing "vitamin D deficiency" to the forefront of public health topics. At almost the same time, multiple social media platforms were discussing whether daily supplementation of 400 IU is sufficient, the safety of taking deep-sea fish oil and VD together, and which brand of VD product has a higher cost-effectiveness. The focus of public attention quickly shifted from "how much to supplement" to "whether the supplement is pure, impure, and stable". Faced with increasingly strict regulatory demands and consumer quality expectations, pharmaceutical companies urgently need to respond with data - can vitamin D and its related substances in soft capsules be accurately, repetitively, and efficiently measured?
Agilent has provided you with an "approximate standard" answer: based on the Agilent 1260 Infinity III platform, the center cut online reverse phase two-dimensional liquid chromatography (RP x RP 2D-LC) has been used for the first time to achieve vitamin D in vitamin D soft capsule products3The one-time injection, complete separation, and quantitative detection of pre vitamin D and five key impurities have solved the analytical problems of "extremely low content", "extremely similar structure", and "easily masked by the matrix".
Figure 1 Vitamin D3And its related chemical structures of substances
Why are traditional methods difficult to measure accurately?
Vitamin D3Easily converted into pre vitamin D under light and heat conditions3Trans vitamin D3Equivalent isomers of sitosterol, phytosterol, and light sterol. These impurities have minimal differences from the main component structure, and their UV absorption characteristics highly overlap; The contents of soft capsules are often carried in matrices such as soybean oil, corn oil, olive oil, and cod liver oil, with high concentrations of triglycerides causing strong background interference. At present, foreign pharmacopoeias or the 25th edition of the Chinese Pharmacopoeia use offline preparation methods for the detection of related substances in VD complex preparations. Whether it is normal or reverse phase preparation, the recovery rate fluctuates due to the numerous sample pretreatment steps, or the separation degree is insufficient due to matrix co outflow, ultimately resulting in an insurmountable "obstacle" between "detection" and "accurate quantification".
Agilent 2D-LC: How to achieve "accurate measurement"
The core idea of single center cutting online two-dimensional liquid phase is to complete the "purification" and "separation" in the same system according to the peak order:
initial stageThe valve position is 1-2, and the one-dimensional chromatographic column completes the sample purification of vitamin D preparation, while the two-dimensional chromatographic column maintains mobile phase equilibrium;
transfer stageThe valve position is 6-1, and one-dimensional chromatography transfers the fraction containing vitamin D and its related substances to the capture column;
Two dimensional analysis stageThe valve position is 1-2, and the two-dimensional pump uses a high proportion of organic phase mobile phase to transfer the sample on the capture column to the two-dimensional chromatography column for separation, achieving the separation and analysis of vitamin D and its related substances.
Figure 2 Schematic diagram of online center cutting two-dimensional column switching system
The Truth and Value Behind Data
Figure 3 First and second dimensional separation spectra of mixed standard solution
(1. Impurity A; 2. Impurity D; 3. Pre vitamin D)34. Impurity E; 5. Vitamin D36. Impurity C; 7. Impurity B)
Figure 4 Analysis spectra and two-dimensional separation amplification spectra of different formulations of vitamin D drops (28min~70min)
1. Impurity A 2. Impurity D 3. Pre vitamin D3（pre-vitamin D3）4. Impurity E 5. Vitamin D3（vitamin D3）6. Impurity C
Figure 3 shows the one-dimensional and two-dimensional chromatograms of the mixed standard, while Figure 4 shows the spectra of the newly prepared vitamin D soft capsule sample and the accelerated 6-month preparation sample. The use of center cut two-dimensional liquid chromatography method can effectively remove interference from matrix components and achieve separation and analysis of principal components and target five impurity components; By comparing the accelerated stability test samples, it can be seen that impurity D (trans VD)3）With the increase of impurity E (sitosterol) content, this method can achieve the analysis of six main related substances of vitamin D3. In addition to the pre VD, trans VD, and sitosterol specified in the 25th edition of the Chinese Pharmacopoeia, it also adds isosterols and photo sterols mentioned in the EP European Pharmacopoeia, providing reliable technical support for improving the quality standards and optimizing the production process of vitamin D3 preparations.
From Single Variety Application to 2DLC Platformization Solution
The analysis and detection of substances related to vitamin D soft capsules is the "tip of the iceberg" of Agilent's two-dimensional liquid phase application plan. Agilent has already extended the two-dimensional liquid phase method to different fields:
From Green Skin Train to High Speed Rail: Agilent tells you how to quickly test vitamins A, D, and E
GB 5009.296-2023 "Determination of Vitamin D in Foods" can use two-dimensional liquid chromatography and online solid-phase extraction two-dimensional liquid chromatography techniques
Latest Articles in One Stop | Agilent 2D-LC Liquid Chromatography Chinese Medicine/Natural Product Application Express (Part 1)
Latest Articles Step by Step | Agilent 2D-LC Liquid Chromatography Application Express for Traditional Chinese Medicine/Natural Products (Part 2)
Conclusion
The public's trust in nutritional supplements comes from every investment made by companies in quality control; And every investment requires reliable, compliant, and transferable analytical tools as the foundation. Agilent 1260/1290 Infinity III two-dimensional liquid phase platform sets a new benchmark for impurity analysis of vitamin D soft capsules with rigorous and industry-leading separation and sensitivity that is consistent with domestic and foreign pharmacopoeias - making "hot search" no longer just a topic, but a starting point for promoting standard upgrading and protecting consumer health.
If you need to obtain detailed application reports, method parameters, and other separation results of different matrices, please reply to the message in the WeChat backend or contact your local Agilent sales personnel.We look forward to working with more pharmaceutical, dietary supplements, special medical food and third-party testing agencies to write "accurate measurement" into the industry consensus and send "reassurance" to thousands of households.