Phospholipid Analysis by 31P-NMR spectroscopy

Jun, 15 2018

What are Phospholipids?

Lipids are important components of biological systems. Phospholipids are a type of lipid molecule and are the major constituents of all biological cell membranes. For instance, when many phospholipids are combined, they form a double layer that is characteristic of all cell membranes (Fig. 1). These complex structures are glycerol-based phospholipids, consisting of a molecule of glycerol to which are attached two fatty acids, a phosphate, and usually one other small molecule (Fig. 2).

Fig. 1   Structure of a cell membrane

Fig. 2   Structure of phospholipids

.

There are two major sources of lecithin: animal and vegetable lecithins. Moreover, lecithins can be used in their native or modified form. Here, modification is a process to improve the emulsifying properties of lecithin.

.

Tab. 1   Lecithin sources (some examples)

.

.

.

Quantitative Phospholipid Analysis – what there is to know? The facts.

All common phospholipid species derive from soybean or other sources and can be determined using 31P-NMR spectroscopy. We from Spectral Service AG developed the phospholipid analysis method by 31P-NMR spectroscopy more than 25 years ago. Consequently, we are the worldwide leader laboratory in quantitative determination of phospholipids using 31P-NMR spectroscopy.

.

Our Team is performing this analysis since its development. Hence, we have the know-how, expertise and experience! Spectral Service AG receives an average of 50 samples on a daily basis of all kind of matrices and from companies all over the world – only for phospholipid analyses. Based on the analytical question, we use 1H-NMR, 13C-NMR, 19F-NMR and 31P-NMR spectroscopy.

.

The quantification of phospholipids is performed according to two different methods: (1) 100% method and (2) absolute method. The United States Pharmacopeia (USP) method for phospholipids in krill oil was developed in the past by Spectral Service according to our standard operation procedures. The AOCS method was established by Spectral Service as well. However, this method is only valid for native soy bean lecithin. The 31P-NMR method for phospholipid analyses is also adopted as the official method by the International Lecithin and Phospholipid Society (ILPS).

.

Spectral Service AG is a GMP and GLP certified laboratory as well as FDA approved. The certificates can be downloaded here. The phospholipid method is validated and within the certification.

.

.

.

Did you know that 31P-NMR is a method used for several analyses, not only phospholipid analyses?

31P-NMR spectroscopy is used for several quantitative determinations. In the addition to the quantification of phospholipids such as PC, LPC, PI, PE (Tab. 2) and glycerophospholipids such as glycerophosphocholine (GPC), glycerophosphoethanolamine (GPE), as well for the quantification of phosphates, diethyl phosphonates and ammonium phosphatides.

.

Tab. 2   Abbreviations of single phospholipids

.

Tab. 3   Chemical Structures of the single phospholipids

.

.

.

In which Matrices is the Phospholipid Analysis possible?



The above listed matrices are only a few examples. If you have a sample from a matrix, which is not listed above, please contact us.

.

.

.

How does a Phospholipid  31P-NMR spectrum look like? Some examples of certain matrices.

Fig. 3   Typical 31P-NMR spectrum of a soy lecithin sample, detail (phospholipids)

.

Fig. 4   Typical 31P-NMR spectrum of an egg lecithin sample, detail (phospholipids)

.

Fig. 5   Typical 31P-NMR spectrum of a krill sample, detail (phospholipids)

.

Fig. 6   Typical 31P-NMR spectrum of a milk sample, detail (phospholipids)

.

.

.

Contact us if you want to know more about phospholipids



                        

Tags:

Aktuelle Methoden

Newspaper

Events