Sample preparation for HPLC analysis

SAMPLE PREPARATION FOR HPLC ANALYSIS OF DRUG PRODUCTS... 

Sample preparation for HPLC analysis of free amino acids usually involves an extraction step (for solid matrices), followed by purification to remove possible impurities. When the aim of the... 

Support Protocol 2 Sample Preparation for HPLC Analysis Support Protocol 3 Converting Glycosidic Isoflavones to Their Aglycones 11.6.10... 

Sample preparation for HPLC analysis of acesulfame-K can be accomplished as described in Sec. I.C. A number of extraction procedures for acesulfame-K have been reported (16,17,33,34,40,44,49). Sodium fumarate and theophyllin can be used as internal standard (17,44). 

Sample preparation for HPLC analysis of alitame will depend on the type of food (16,33), and complex matrices may be clarified with Carrez solutions or by means of C18 disposable cartridge (33), as described in Sec. I.C. 

Hill, N.S., Rottinghaus, G.E., Agee, C.S. and Schultz, L.M. (1993) Simplified sample preparation for HPLC analysis of ergovaline in tall fescue. Crop. Set., 33, 331-333. 

Sample preparation for saccharin analysis by HPLC can be performed as indicated in Section I.C. Methods for extraction have also been described for desserts and sweets containing food thickeners (38) soy sauce, orange juice, and yogurt (60) chewing gum (17,39), and different food samples (42). Aminobenzoic acid, theophyllin, sodium fumarate, and adenine sulfate have been used as internal standards (17,31,39,44). 

Sample preparation for color analysis will depend on the type of food sample. Liquid samples such as beverages can be filtered through a 0.45 /rm pore membrane filter and injected directly in the HPLC. Carbonated beverages are degassed. Beverages containing suspended solids are filtered or centrifuged to eliminate suspended solids (143,156,160). 

Barbiturates can be prepared for HPLC analysis by dissolution of the drug sample in methanol at a chosen concentration, followed by removal of any sofid particulate material by filtration, etc. A typical set of HPLC operating conditions used for the analysis of barbiturates is shown in Table 9.4. 

Sample preparation before HPLC analysis differs for juice and peel oil samples. Juice samples were extracted 1 1 on a weight basis with solvent (10% w/w dichloromethane + 90% hexane) (40 g juice + 40 g solvent), the solvent was separated and evaporated to 0.5 g using a Turbovap 11 model concentration This concentrated mixture was injected into the HPLC. Extraction recovery for the PMFs was determined to be 89 %. Oil samples were diluted to 10% (w/w i in ethanol and injected directly. In both cases, injection volumes of 5 jL were used. All oil samples in this study were winterized for at least 30 days at a temperature of 4 C or less. 

One reason that we felt it was possible that decomposition of the nanombe system would be observed was an experiment that we had done earlier with the n-decyl tetramer. The tetramer was crystallized into either bilayers or capsnles by changing the crystallization solvent. We dissolved samples of each crystal in EtOAc in preparation for HPLC analysis [25]. When either sample was injected into the HPLC, the chromatogram observed was essentially identical. This suggested that the system was highly dynamic, despite the reported ability of pyrogallol[4]arene capsules to retain their integrity in aqneons solution [31]. 

An analytical chemist who is able to optimize his or her sample preparation and HPLC analysis can very well decide whether to use an internal standard, whether to calculate the straight Hne with or without weighting, and whether or not to consider an intercept. Obviously, it is mandatory that one can give reasons for these decisions. 

Carotenoid pigments were extracted by chloroform-acetone-isopropyl alcohol /2 l l/ after acetone extraction as described earlier. Lipids of different parts were extracted and their fatty acid composition were analysed by GLC. Tocopherols of different parts of the fruits were extracted, saponified and prepared for HPLC analysis according to Speek and co-workers. Organic acids were prepared by a method described previously. Following preparation the samples were redissolved in a minimal volume of the HPLC eluent. 

In conclusion, SPME is an ideally suited sample preparation method to prepare samples for GC or GC-MS. Most compounds well suited for GC analysis can be extracted and concentrated using SPME, which is easy and results in excellent analytical performance. SPME is, however, less well adapted as a sample preparation for HPLC to study polar or large molecules. 

Method 3 - Physical separation of parts. Cranberries were physically separated by removing the peel and squeezing the juice from the remaining solid. Samples were prepared for HPLC analysis from the peels, solids, juice and the whole berry by extraction with 98 2 methanol/acetic acid. Solutions were passed through Whatman Puradisc 13 mm/0.45 pm filters prior to HPLC analysis. The samples were also analyzed spectrophotometrically for total flavonoid and anthocyanin content using the method of Lees and Francis (4). The data are shown in Table III. 

Sample preparation for analysis by hyphenated methods requires some additional planning when compared to nonhyphenated methods. All steps, extraction, concentration, and final solvent selection must take into consideration and be compatible with all the components of the hyphenated instrumentation. For gas chromatographic methods, all the components in the mixture must be in the gaseous state. For liquid chromatography (LC) or high-performance liquid chromatography (HPLC), the samples of the analytes of interest can be solids or liquids, neutral or charged molecules, or ions, but they must be in solution. If the follow-on analysis is by MS, then each of the analytes may require a different method of introduction into the MS. Metals and metal ions may be introduced by HPLC if they are in solution but commonly are introduced via AAS or inductively coupled plasma (ICP). Other analytes may be directly introduced from HPLC to MS [2],... 

All reagents and solvents were used as received (Sigma-Aldrich) if not stated otherwise. NOL-130 stab initiation mix and preformed, 19 mg graphite-blended l,3,5-trinitro-l,3,5-triazacyclohexane (RDX) pellets were purchased from Day Zimmerman (DZI). Samples prepared for LC-MS analysis were dissolved in ammonium hydroxide and run utilizing a Phenomenex Gemini C6-Phenyl column (4.6 mm X 150 mm) and a mobile phase of 20 mM ammonium acetate in water pH 7.02 at 0.75 ml,-min The HPLC analysis is done using... 

HPLC has been shown as an effective method in the fractionation and preparation of AHLs for structural analysis. Preparation of AHL-containing samples for HPLC analysis requires their extraction with organic solvents such as dichloromethane or ethyl acetate [37]. Usually, C8 reverse-phase columns are employed and samples eluted with either gradient or isocratic mobile phases, e.g. acetonitrile-water. Fractions are analysed for the presence of AHLs using the biosensors described in the previous section. AHLs from active fractions can then be identified using more powerful techniques (see following sections). 

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