Ultrasound-assisted enzymatic indirect determination of total 3-monochloropropane-1,2-diol esters in canned fish oil fraction.

A novel, fast, and cost-effective indirect enzymatic method was successfully developed to assess the total 3-monochloropropane-1,2-diol (3-MCPD) in canned food's oil fraction by the action of Burkholderia cepacia lipase. The total 3-MCPD were derivatized with n-Heptafluorobutyrylimidazole (HFBI) for GC-MS analysis during dispersive liquid-liquid microextraction (DLLME). An asymmetrical 2213//8 screening design was used to study the influence of critical factors on the method's effectiveness. The analytical features of the proposed method were assessed following Food and Drug Administration (FDA) guidelines using extra virgin olive oil (EVOO) as a blank sample. Outstanding results were achieved in terms of linearity (r2 = 0.9995), sensitivity, precision (2.1 % to 10.4 % RSD), and accuracy (98.7 % ≤ recovery ≤ 101.9 %). Method efficacy was tested by comparing the results of 10 edible oils for total 3-MCPD with those reported in previous works. A total of 41 samples were analyzed. The lowest 3-MCPD content was found in samples of albacore canned in EVOO oil, while the highest amounts were found in albacore, mackerel, and Atlantic saury samples, all preserved in refined sunflower oil.

Microextraction by packed sorbent followed by ultra high performance liquid chromatography for the fast extraction and determination of six antidepressants in urine.

The growing use of antidepressants in recent years has led to their increasing presence in forensic analyses. In this work, microextraction by packed sorbent followed by ultra-performance liquid chromatography with photodiode array detection provided a fast method for determining the antidepressants mirtazapine, venlafaxine, escitalopram, fluoxetine, fluvoxamine, and sertraline in human urine. The microextraction conditions (viz., type of sorbent, number of draw-eject extraction cycles or strokes, sample volume and pH, and type and volume of washing solution and eluent) were optimized by using an experimental design. The ensuing analytical method was validated in terms of linearity (25-1000 ng/mL urine), limit of detection (lower than 7.1 ng/mL), limit of quantification (25 ng/mL), precision (4.7-15.1% as relative standard deviation), and accuracy (80.4-126.1% as mean recovery for four replicate determinations). The proposed method allowed the six target antidepressants to be determined at concentrations from therapeutic to toxic levels. The application to small volumes (300 µL) of urine afforded fast extraction of the analytes and provided results on a par with those of existing clinical and forensic alternatives.

Solid-phase micro-extraction procedure for the determination of 1,3-dichloro-2-propanol in water by on-fibre derivatisation with bis(trimethylsilyl)trifluoroacetamide.

The headspace solid-phase micro-extraction technique with on-fibre derivatisation followed by gas chromatography-tandem mass spectrometry has been evaluated for the analysis of 1,3-dichloro-2-propanol in water. An asymmetric factorial design has been performed to study the influence of five experimental factors: extraction time and temperature, derivatisation time and temperature and pH. The best extraction performance is achieved in the headspace mode, with 5 mL stirred water samples (pH 4) containing 1.3 g of NaCl, equilibrated for 30 min at 25 degrees C, using divinylbenzene-carboxen-polydimethylsiloxane as the fibre coating. On-fibre derivatisation has been used for the first time with 50 microL of bis(trimethylsilyl)trifluoroacetamide at 25 degrees C during 15 min, leading to effective yields. The proposed method provides high sensitivity, good linearity and repeatability (relative standard deviation of 5.1% for 10 ng mL(-1) and n = 5). The limits of detection and quantification were 0.4 and 1.4 ng mL(-1), respectively. Analytical recoveries obtained for different water samples were approx. 100%.

Microwave-assisted extraction and HPLC-DAD determination of drugs of abuse in human plasma.

A sample preparation procedure using microwave energy is proposed for the determination of morphine, 6-acetylmorphine, codeine, cocaine, cocaethylene, benzoylecgonine, methadone, and 2-ethylene-1,5-dimethyl-3,3-diphenylpyrrolidine in human plasma. A screening asymmetrical factorial design was used to identify the most suitable extraction conditions as regards solvent, temperature, and extraction time. The target drugs were quantified by high-performance liquid chromatography with diode-array detection. The use of microwave energy was found to reduce solvent consumption and extraction time compared with solid-phase extraction. The detector response was linear over the drug concentration range of 0.05-2.0 microg/mL in human plasma. The precision and accuracy were good, with values less than 8% and 7%, respectively. Drug recoveries from spiked samples ranged from 69 to 81%. The proposed method was successfully applied to a number of forensic cases.

Microwave assisted extraction of drugs of abuse from human urine.

Microwave assisted extraction (MAE) was used to extract drugs of abuse from urine samples for the simultaneous determination of morphine, codeine, 6-acetylmorphine (6AM), cocaine, cocaethylene, benzoylecgonine (BEG), methadone and 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP) by high performance liquid chromatography with diode array detector (HPLC-DAD). The working wavelengths used were 285 nm for morphine, codeine and 6AM; 233 nm for cocaine, cocaethylene and BEG; and 292 nm for methadone and EDDP. The mobile phase was a gradient of acetonitrile and phosphate buffer at pH 6.5. A full factorial design was used to identify the most suitable extraction conditions as regards pH, solvent and time of extraction. The optimum conditions thus established provided analyte recoveries from 61% to 109%. The detector response was linear over the drug concentration range 0.1-4.0 microg ml(-1) in urine. The within- and between-day precision and accuracy were less than 8% and 6.5%, respectively. The method was applied successfully to samples obtained from Galician hospitals and courts.