Dynamic Light Scattering for Particle Size Analysis
Dynamic light scattering is a technique that allows for the measurement of the hydrodynamic size of small particles in suspension. These can include liposomes, micelles, lipid droplets, proteins, polymers, and nanoparticles. The reported data will reflect the distribution of particle sizes present in suspension. We apply this method to our own custom liposome formulations, and offer this service to customers who would like to test their own formulations.
Zeta potential is generally used as an indicator of stability of colloidal suspensions, as it is an approximation of the surface charge density of particles in suspension. A highly positive or highly negative zeta potential indicates a suspension that has excellent stability, while a suspension with zeta potential near zero will tend to aggregate more rapidly.
Particle Size Analysis and Zeta Potential Analysis
If you order both particle size analysis and zeta potential analysis, for the same sample, we offer a discounted combination price. They must be ordered at the same time and must be for the analysis of the same sample to receive the discount.
Thin Layer Chromatography (TLC)
Thin layer chromatography performed against appropriate standards provides a fast and accurate means to determine the identity of lipids classes present in a sample. This technique is typically the starting place for any sample of unknown composition. This analysis may not be suitable for samples with limited amounts.
Molecular Characterization of an Unknown Lipid Sample
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We can combine any of our identification methods to provide a structural analysis of your unknown lipid sample. The combination of various NMR methods along with mass spec can be powerful in determining the lipids of your unknown sample.
Phosphorus Content by UV/VIS Spectrophotometry
This is a quantitative method which measures total elemental phosphorus after sample digestion. The results can be used to calculate information such as % phosphorus and concentration of a phospholipid solution. Weight % determination of a purified lipid may be measured relative to theoretical phosphorus content.
Peroxide Oxidation Value (POV)
Peroxide oxidation value is a semi-quanitative measurement of the degree of early oxidation events in lipid and phospholipid preparations. The method is based on American Oil Chemist’s Society Method. Results are reported as mEq peroxide / Kg of sample.
Water Content by Karl Fischer Titration
Water Content by Karl Fischer Titration measures the amount of water in sample as either % by weight (w/w) or % by volume (v/v). Your sample must be soluble in non-polar solvents such as alcohols, alkanes and chlorinated hydrocarbon solvents. Acetone and other ketone solvents are not acceptable for apparatus.
High Performance Liquid Chromatography with Evaporative Light Scattering Detection (HPLC/ELSD) (Area Under Curve)
High Performance Liquid Chromatography coupled with an Evaporative Light Scattering Detector (HPLC/ELSD), provides separation and quantitation of lipid compounds in a sample. Methods include normal phase and reversed phase techniques for measurement of known compounds within a formulation. Separation and quantitation of lipids and phospholipids in a complex mixture or matrix is one of our specialties.
High Performance Liquid Chromatography with Evaporative Light Scattering Detection (HPLC/ELSD) (Weight/Weight)
High performance liquid chromatography coupled with an evaporative light scattering detector (HPLC/ELSD) and the appropriate calibration standard(s), can provide separation and quantitation of lipid compounds in a sample. This option applies multi-point calibration and more detailed sample preparation to provide you with weight % results for each lipid analyzed.
Electospray Mass Spectroscopy (ESMS)
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Electrospray Mass Spectrometry (ESMS) is a low fragmentation technique whereby molecular weight and structural information can be obtained from a small sample amount. Infusion of lipid solutions into the electrospray or atmospheric chemical ionization interface can identify the heterogenous molecular species present. Structural information or structural confirmation can be obtained utilizing tandem mass spectral (MS/MS) or MS/ion trap techniques.
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Quantitative trace analysis for targeted analytes and degradation products in a sample is possible at sensitivities of microgram to picograms with LC/MS/MS. Customers should inquire on available services and technical aspects of performing sample analysis prior to submission of samples. Method development and validation are available.
GC-FAME Analysis (AUC)
Our experience with gas chromatography for the characterization of fatty acids is extensive. Use of modern capillary columns with a choice of stationary phases, coupled with flame ionization detection support a vast range of possible analytical applications; the most popular request being percent composition of fatty acids present in a sample (sample preparation techniques allow for assay of esterified fatty acids only or total fatty acids (esterified and free). This method reports the fatty acids present in your sample with percentages based on the area under each chromatographic peak. FAME standards from C4 through C24 are used with each analysis.
GC-FAME Analysis (weight/weight)
Quantitation of fatty acids on a weight percent basis employs internal standards spiked into sample matrix upon extraction / preparation. This method provides a more accurate reporting for the amount of each individual fatty acid present in your sample with the use of both internal standards and external calibration curves.
Ion Chromatography separates ions based on their affinity to the ion exchanger. This technique can be used to confirm the salt form of a compound (such as ammonium salt form versus sodium salt form), characterize a raw material, and test water quality.
Fourier Transformed Infrared Spectroscopy (FTIR)
Qualitative analysis by mid-range Fourier Transform IR (FTIR) can be performed on solids as well as liquids by ATR (Attenuated Total Reflectance). Best results are obtained on purified materials. Functional groups are readily identified to aid in the assignment of chemical structure and/or formula. Spectral matching can be performed against any of Avanti’s lipid compounds for confirmation.
Analytical Method Development, Qualification, and Validation
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We perform method design and development for a vast array of assays including NMR, HPLC-ELSD, LC-MS/MS and GC. The goal of method qualification is to demonstrate a method is fit for the intended use. In most instances this requires some demonstration of specificity, accuracy and linearity. As the life cycle of products develop and change we are capable of moving methods from method development through full validation. Method validation requires assessment of clearly defined and agreed upon criteria utilizing a set of assays that demonstrate a robust reproducible method. A protocol is initiated and approved prior to the beginning of validation. The protocol includes experimental design as well as acceptable limits for method performance. The experiments routinely performed in validation include: system suitability, linearity, limit of detection, limit of quantitation, specificity, accuracy, precision (repeatability, reproducibility and intermediate) and robustness (CFR 211.194(a)(2)). We recognize that as the product lifecycle moves forward, and technology constantly changes, validated methods undergo a lifecycle of their own which includes continued method evaluation.
Stability Testing of Lipid Related Products
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Avanti can perform stability testing of lipid-related products or raw materials utilizing a combination of any of our assays. Development of a testing protocol based on ICH Stability Testing Guidelines is available. Samples are sent to Avanti on a pre-determined schedule for analysis. Results are reported back to you upon completion of testing at each time point. Following an initial consultation, we will provide a quotation for stability testing services.
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Sometimes all you need is an idea to get started. Our experience in phospholipid and lipid analysis is available to you through direct conversation with one of our many technical experts. Avanti requires initial consultation on new projects and on method development / validation, or molecular characterization. This assures the best, most accurate data can be obtained in the shortest amount of time.
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Please note that all of Avanti Analytical Services are performed in a Quality Control Laboratory by a trained analyst and is intended for research use only. All work is documented and reviewed by a second trained analyst but does not involve the review of the cGMP Quality Unit of Avanti. If you require cGMP analysis of a sample, please see our cGMP Testing Services page for more information.