Simultaneous determination of caffeine, theobromine, theophilline, paraxanthine and nicotine in human milk by liquid chromatography with diode array UV detection

A liquid chromatography-diode array UV detection (LC–UVDAD) method for the simultaneous determination of the alkaloids Nicotine, Caffeine, Theobromine, Paraxanthine and Theophylline is described. The chromatographic separation was achieved on a LC-18-DB column using 20:80 methanol:buffer (5 mM sodium octane sulphonate, 10 mM citric acid adjusted to pH 5.8 with triethylamine) as mobile phase. The method has been applied to human milk samples. The overall procedure had % recoveries ranging from 60.2 ± 0.6 (theobromine) to 98.6 ± 0.4 (caffeine). The within-day (n = 5) and between-days (n = 5 over 5 days) coefficients of variation in milk ranged from 3.7% (caffeine) to 4.7% (theobromine) and from 5.1% (caffeine) to 6.7% (theobromine). Estimated LOD and LOQ in milk ranged from 8 (caffeine) to 13 (nicotine) ng/ml and from 24 (caffeine) to 34 (nicotine) ng/ml, respectively. Samples naturally contaminated with the target analytes were found

Simultaneous determination of salicylates and benzoic acid in food by SPME-LC-UV-DAD

Salicylates, i.e. acetylsalicylic acid (aspirin) and their derivatives, are used as fungicidal and antimicrobial agents in pharmaceuticals preparations (external use) as well as in the treatment of inflammatory processes as antipyretic and analgesic drugs (internal use). Salicylates have been also used in beverages and foods for preservation, but it has been forbidden since the sixties in several countries due to its toxicity. These chemicals occur also naturally in many plants, including many fruits vegetables, and herbs. Salicylates are generally regarded as safe for adults, even if high enough doses are harmful to everyone. Unfortunately, there is a small percent of the population for which even a small dose of salicylates can be a problem. Some adults and children may develop symptoms and health problems from salicylates which are dose-related. This is called ‘Salicylate Sensitivity’ or ‘Salicylate Intolerance’ (urticaria, angiooedema, rhinitis, bronchial asthma and recurrent nasal polyps). The chronic nature of some of these clinical presentations, without other obvious cause, may suggest an underlying etiology related to dietary salicylates. This cannot be established however, until the salicylate content of different food and drinks is known. Data on the salicylate content of foods are scarce and contradictory. Our aim was to develop an accurate analytical method to measure the salicylates content of food. Existing papers on this topic have been essentially based on chromatographic techniques, after purification of the analytes by means of complicate isolation procedures. A good alternative could be represented by the use of solid-phase microextraction (SPME), a solventless technique initially coupled to GC and later interfaced also to LC [3]. This work presents the first solid-phase microextraction (SPME)–LC–UV-DAD method for the simultaneous determination of salicylates and benzoic acid in food samples