RESUMO
A method for rapid determination of γ-hydroxybutyric acid (GHB) in beverages (water, sodas, beer) and urine was established by direct analysis real-time mass spectrometry (DART-MS). Samples were analyzed directly after dilution with mixture of methanol and water(1:1,V/V). Instrument parameter settings were optimized to obtain the sensitive and accurate determination of GHB. At the sample introduction speed of 0.5 mm/s, high intensity of[M-H]- ions for GHB were observed in the negative ion and selection ion monitoring mode by utilization of high purity helium gas at 350℃. For different samples of water,sodas,beer and urine,the limits of detection (LODs) (S/N=3) were in the range of 1-2 μg/mL, while the limits of quantification (LOQs) (S/N=10) were in the range of 3-5 μg/mL. The linear correlation coefficients of the standard curves with different sample matrixes were between 0.9899 and 0.9980. The recoveries were in the range of 80.8%-115.2% with the relative standard deviations of 1.9%-12.8%. With its rapid analysis and simple pretreatment steps,the method is expected to have a strong advantage in the rapid screening analysis of large quantities of beverage and urine.
RESUMO
Objective To establish a method for rapid detection of JWH-018, JWH-250 and AM-2201 in blood by direct analysis in real-time coupled with tandem mass spectrometry. Methods These samples were extracted by acetonitrile-methanol (4:1), using DART 12Dip-it automatic sampling system. They were analyzed by positive ion and MRM mode. Results The detection limits of JWH-018, JWH-250 and AM-2201 were in good linearity in the range of 0.02-5.00μg/mL. The correlation coefficients were above 0.99 and the detection limits were 0.016μg/mL, 0.003μg/ mL and 0.017μg/mL, respectively. The intra-day and inter-day RSD were less than 15%. Conclusion The method has the advantages of high sensitivity and good accuracy. The sample processing is simple and can be analyzed in short time. This method is suitable for the analysis of JWH-018, JWH-250 and AM-2201 in practical cases.
RESUMO
The paper presents a flexible and simple direct analysis in real-time ( DART) device without grid electrode for mass spectrometer injection. It contained inert carrier gas, ionizer, heater and temperature-controller etc. Excluding the grid electrode and then reducing the structure units, the device could be easy to build up in low cost and flexible to connect with a variety of mass spectrometers. The experimental conditions like the kind of carrier gas, flow rate and temperature were investigated for the device. By using argon as carrier gas, flow rate as 7. 5 L/min, and temperature of heat tape as 300 ℃, the device was used to analyze benzene alcohol, linoleic acid, dichlorvos emulsion, mosquito coils, citrus peel, and sample ( propranolol hydrochloride) on thin-layer plate combined with mass spectrometer. The results were accurate and the device was stable and reliable.