Changes in the levels of headspace volatiles, including acetaldehyde and formaldehyde, in red and white wine following light irradiation.

The effects of fluorescence light irradiation on the changes in the levels of volatiles, especially acetaldehyde and formaldehyde, were determined in red and white wines. Three different red or white wine brands were mixed and subjected to light irradiation for 5 days. Generally, the levels of total volatiles in white wine were higher than those in red wine were and decreased during light irradiation. The level of 1,1,6-trimethyl-1,2-dihydronaphthalene, an aromatic compound commonly found in aging wine, decreased significantly following light irradiation (p < 0.05), whereas those of acetaldehyde and formaldehyde increased significantly in white wine (p < 0.05). Furthermore, the formaldehyde content in white wine was higher than that in red wine. Thus, light irradiation promotes the decomposition of major volatiles to a greater degree in white wine than in red wine. This implies that white wine may require more attention and caution against light exposure than red wine. PRACTICAL APPLICATION: Red and white wines are two globally consumed alcoholic beverages; several factors influence their quality. This study evaluates the effects of light irradiation on the profiles of headspace volatiles, such as formaldehyde and acetaldehydes, which are harmful chemicals. Generally, the levels of total headspace volatiles decreased during storage, while those of acetaldehyde and formaldehyde increased markedly in white wine. This increase in aldehyde levels suggests that wines should not be exposed to light irradiation. The results of this study will help wine producers, distributors, and consumers maintain wines with low contents of acetaldehyde and formaldehyde.

Inorganic arsenic contents in ready-to-eat rice products and various Korean rice determined by a highly sensitive gas chromatography-tandem mass spectrometry.

Rice and rice products have been reported to contain high contents of toxic inorganic arsenic (iAs). The inorganic arsenic contents in microwavable ready-to-eat rice products (n=30) and different types of Korean rice (n=102) were determined by a gas chromatography-tandem mass spectrometry (GC-MS/MS). The method showed low limit of detection (0.015pg), high intra- and inter-day repeatability (<7.3%, RSD), and recovery rates (90-117%). The mean iAs content in the ready-to-eat rice products was 59µgkg-1 (dry weight basis). The mean iAs contents in polished white, brown, black, and waxy rice were 65, 109, 91, and 66µgkg-1, respectively. The percentages of ready-to-eat rice products, white, brown, black, and waxy rice containing iAs over the maximum level (100µgkg-1) set by EU for the infant foods were 17, 4, 70, 36 and 0%, respectively.

One step derivatization with British Anti-Lewsite in combination with gas chromatography coupled to triple-quadrupole tandem mass spectrometry for the fast and selective analysis of inorganic arsenic in rice.

We developed a new fast and selective analytical method for the determination of inorganic arsenic (iAs) in rice by a gas chromatography - tandem mass spectrometry (GC-MS/MS) in combination with one step derivatization of inorganic arsenic (iAs) with British Anti-Lewsite (BAL). Two step derivatization of iAs with BAL has been previously performed for the GC-MS analysis. In this paper, the quantitative one step derivatization condition was successfully established. The GC-MS/MS was carried out with a short nonpolar capillary column (0.25 mm × 10 m) under the conditions of fast oven temperature ramp rate (4 °C/s) and high linear velocity (108.8 cm/s) of the carrier gas. The established GC-MS/MS method showed an excellent linearity (r(2) > 0.999) in a tested range (0.2-100.0 µg L(-1)), ultra-low limit of detection (LOD, 0.08 pg), and high precision and accuracy. The GC-MS/MS technique showed far greater selectivity (22.5 fold higher signal to noise ratio in rice sample) on iAs than GC-MS method. The gas chromatographic running time was only 2.5 min with the iAs retention time of 1.98 min. The established method was successfully applied to quantify the iAs contents in polished rice. The mean iAs content in the Korean polished rice (n = 27) was 66.1 µg kg(-1) with the range of 37.5-125.0 µg kg(-1). This represents the first report on the GC-tandem mass spectrometry in combination with the one step derivatization with BAL for the iAs speciation in rice. This GC-MS/MS method would be a simple, useful and reliable measure for the iAs analysis in rice in the laboratories in which the expensive and element specific HPLC-ICP-MS is not available.