Mr. Pacheco,

You are lookin at easy method; or accurate, selective, sensitive, precise and exact method? Also, what you have reflected in mind under 'easy' method, generally?

You can extract Vitamin D from your sample by diethyl ether (2 times extraction will do) and further purification can be done by centrifugation and filtration (by using a cartridge) before injecting to the column

Article Development of an analytical method for the quantitative det...

Article Significance of previtamin D chromatographic resolution in t...

Article Potential intake of vitamins "A" and "D" through branded int...

One HPLC method may be better or worse than another. Depends on the specific "food". D2 and D3 alone are easy. When they are mixed in with other compounds, then things get more complicated. Sample preparation and using a method that is selective for the sample is very important. Please try a keyword search on the web (e.g. GOOGLE) to find many example articles, papers, application notes and examples. That will give you an idea of what is available.

Dear Sidney Pacheco thank you for your interesting question. In addition to the potentially useful references provided by Nantenaina Tombozara please also see this interesting article entitled

Convenient Analysis of Vitamin D in Cheese and Other Food Matrixes by Liquid Chromatography/Mass Spectrometry

Article Convenient Analysis of Vitamin D in Cheese and Other Food Ma...

With this study the authors present a rather easy and convenient method to determine vitamin D in various food items such as cheese, milk, cereals, non-carbonated soft drinks, and juice by employing liquid chromatography / mass spectrometry (LC/MS). The advantage of this method is that is does not require a time-consuming preliminary chromatographic step by HPLC.

Mr. Pacheco,

Please, consider the following comments on work:

Convenient Analysis of Vitamin D in Cheese and Other Food Matrixes by Liquid Chromatography/Mass Spectrometry, J. AOAC Int. 90 (2007) 1340, provided by Mr. Edelmann, because of the analytical protocol, therein, uses classical approach to quantify mass spectrometric (MS) experimental variables, which, however, does not provide superior method performences required for quantitative analysis of foods.

Of course, there should be accounted for that:

(i) The paper is relatively old (2007) and does not reflect more recent trends in the quantitative mass spectrometry; and

(ii) the author's affiliation is a food Coumpany, which analyses are restricted to Directives. The latter Directives, however, are updated slowly. Thus, they do not reflect innovations in methodological developments, even currently.

Thus, as Mr. Edelmann, has properly underlined, the aforementioned paper could be only potentially useful to you, due to the following reasons:

(A) The experimental design is based on the method of mass spectrometry, which is the only currently available exact method for quantification having superior instrumental characteristics; and (B) the author has provided a useful sample pretreatment allowing a direct analysis by mass spectrometry.

However, toward the data-processing of the experimental MS variables, there are the following remarks associated with a drawback of the classical concept of quantification. Please, concentrate on Figure 5 (page 1344.) The author correlates results from LC-UV and LC-MS measurements, however, there is a lack of data on standard deviations and errors of these measurements. If these latter data were given, then the chemometric parameter /r/ sould have a significantly lower value, than the given value of 99.04 %. Why?

First, the quantification of UV-spectroscopic patterns is characterized by a significant error contribution, due to mathemathical data processing within the framework of measurements in multiplications. Consider more detail on discussions [A,B], below. The comments on the vibrational spectroscopies are valid to UV-VIS one.

Second, the MS variables m/z- and 'intensity' (I) values are characterized by the so-called fluctuations. They are, due to interactions of analyte MS ions with the so-called continuum during the MS measurements. These fluctuations are results from the fact that the MS outcomes reflect exactly the energetics of the analyte species. Thus, any perturbation/fluctuation fo the energy of MS ions yields to perturbation/fluctuation of the corresponding m/z- and I-values. The relationship between energy and the mass is given by the well-known Einsteins' s law.

The relationship between m/z and I-values from MS experiments we have modeled and reported to our more recent contribution (Consider, reference [1], equation (5), given below.)

The further development of this our own-authored (to me and my co-author's contribution according to the shown authorship) stochastic dynamic theory and model formulas presented in reference [1] for quantification of experimental mass spectrometric variables has shown that within the framework of this theory the analytes in mixtures are quantified exactly or absolutely, showing coefficient of linear correlation between theory and experiment /r/ = 0.99997-1 at anlyte concentrations of pg.(mL)-1 and ng.(L)-1. Our method is validated by means of chromatography. Please, consider references [2,3].

[A] [https://www.researchgate.net/post/HPLC_how_to_calculate_violaxanthin_area_if_it_overalps_with_neoxanthin]

[B] [https://www.researchgate.net/post/Sensitivity_Coefficient_in_Uncertainty_Calculations_for_HPLC_assay_method_UV_assay_methods_and_pH_measurement]

[1] Bioorganic Chemistry, 93 (2019) 103308

A mass spectrometric stochastic dynamic diffusion approach to selective quantitative and 3D structural analyses of native cyclodextrins by electrospray ionization and atmospheric pressure chemical ionization methods

Bojidarka Ivanova, Michael Spiteller

[2] Stochastic Dynamic Mass Spectrometric Approach to Quantify Reserpine in Solution; Bojidarka Ivanova, Michael Spiteller

Analytical Chemistry Letters, 10 (2020) 703-721; Received 13 Oct 2020, Accepted 16 Dec 2020, Published online: 28 Jan 2021

Download citation https://doi.org/10.1080/22297928.2020.1865834

[3] Steroids, 164 (2020) 108750

Stochastic dynamic mass spectrometric quantification of steroids in mixture — Part II; Bojidarka Ivanova, Michael Spiteller

Since, I have mentioned above the theory behind contributions [1-3] is our authored method, if you have any questions, regarding, its application to analysis of foods, please do not hesitate to ask them, herein. They shall be answered, accordingly.

There remains to be clarified, what you understand under an 'easy' method? Because of, the complexity of a method depends on the functional relationships of the parameters leading to an observation of a given phenomenon in the Nature under a set of experimental factors. Thus, we are able to model the functional dependence writing the law which a phenomenon obeys. However, we are unable to create naturally observed phenomena and their functional relationships, themselves.

(The analysis within the framework of our theory takes about 10 minutes depending on the complexity of the analyte mixture, of course.)

there is a review that refers to different extraction and analysis methods for determination of Vitamins from different matrixes. I hope it can help you.

Best

Molecules 2018, 23(6), 1484; https://doi.org/10.3390/molecules23061484

(A Review of the Extraction and Determination Methods of Thirteen Essential Vitamins to the Human Body: An Update from 2010)