Aflatoxins contamination in spices and processed spice products commercialized in Korea

A survey for total aflatoxins (aflatoxins B₁, B₂, G₁, and G₂) was conducted on 88 spices and processed spice products commercialized in Korea. The presence of aflatoxins was determined by high-performance liquid chromatography (HPLC) with fluorescence detector using immunoaffinity column clean-up. Total aflatoxins (AFs) are detected in 12 samples (13.6% of incidence) including seven red pepper powder, two red pepper pastes (Kochujang), two curry and one ginger product. The contamination levels are 0.08–4.45 μg/kg as aflatoxin B₁ and 0.08–4.66 μg/kg as AFs. The liquid chromatography–tandem mass spectrometry (LC–MS/MS) analysis on contaminated samples was conducted for the confirmation of detected aflatoxins. The 12 samples which showed aflatoxins by HPLC/FLD were confirmed as aflatoxins by LC–MS/MS.     

Rapid quantitation of curcumin in turmeric via NMR and LC–tandem mass spectrometry

A rapid, sensitive and accurate ¹H NMR method has been developed for the quantitation of curcumin isolated from Curcuma longa rhizome (turmeric) extract, the results of which were compared with a validated LC–MS/MS method. The relative standard deviations of the methods were found to be 2.49% and 3.48% for the ¹H NMR and LC–MS/MS methods, respectively. The correlation coefficients were 0.998 for ¹H NMR and 0.995 for LC–MS/MS assay in the calibration range. The recoveries at 5 mg mL⁻¹ and 50 μg mL⁻¹ concentrations averaged to 99–101% for both techniques, respectively. The uncertainty of the measurement of curcumin via ¹H NMR spectroscopy was determined to be 5.80% while in LC–ESI-MS/MS method was 7.38%.     

Identification of irradiated meats by determining o- and m-tyrosine as markers

To identify the irradiated meats, various parameters that affect extraction efficiency of tyrosine positional isomers were evaluated. The optimum procedure employed simple extraction by 0.1% formic acid and protein precipitation by acetone. Baseline separation for the extract was carried out on LC–fluorescence detection (FLD) and LC–tandem mass spectrometry (MS/MS). The LC–FLD and LC–MS/MS method had LOD of 1.7–2.1 and 0.3–0.5 ng/mL, respectively, and showed excellent linear correlation over three orders of magnitude, obtained ideal recoveries (78.68–88.90%) and RSD (≤ 8%). The methods were successfully applied in multiple samples. For o- and m-tyrosine, the order of descending trend was: chicken > beef > hairtail > pork and chicken > hairtail > beef > pork, respectively. The radiation dose could be quantitatively evaluated by the nonlinear correlation (y = A₀x² + A₁x + A₂) with coefficients of determination r² > 0.998 in individual meat samples.     

The determination of vitamin D3 in bovine milk by liquid chromatography mass spectrometry

A renewed international interest in vitamin D status has revealed significant deficiencies in several populations, including Australia. Vitamin D exists in two forms, cholcalciferol (D₃) and ergocalciferol (D₂). The main source of vitamin D₃ is from exposure of 7-dehydrocholesterol present in the skin to UV irradiation. However, there is an absolute requirement for vitamin D through proper dietary intake if humans live in the absence of sunlight or exclusively indoors. Bovine milk is considered to be a good dietary source of vitamin D₃, even though the levels are quite low. This paper describes robust methods using liquid chromatography–linear ion trap mass spectrometry (LC–MSⁿ) and liquid chromatography–tandem mass spectrometry (LC–MS/MS) to measure the levels of vitamin D₃ in fresh bovine milk (0.05 μg/100 ml), commercial (natural and fortified) milk samples (0.01–2 μg/100 ml) and a dairy based infant formula (8 μg/100 g), without the need for extensive clean-up procedures. The limits of quantification (LOQ) are 0.01 μg/100 ml and 0.02 μg/100 ml for LC–MSⁿ and LC–MS/MS, respectively. Recoveries of vitamin D₃ added to the samples prior to saponification were satisfactory (range 60–90%). 25-Hydroxyvitamin D₃ was not present in any of the samples analysed (LOQ = 0.01 μg/100 ml, recovery range 30–40%).     

Further data on the levels of emerging Fusarium mycotoxins enniatins (A,A1, B,B1), beauvericin and fusaproliferin in breakfast and infant cereals from Morocco

Sixty-eight samples of cereals products, including breakfast cereals (n = 48) and infant cereals (n = 20), purchased from supermarkets and pharmacies in Rabat-Salé area from Morocco were analysed for the determination of six emerging mycotoxins: four enniatins ENs (ENA, ENA1, ENB and ENB1), beauvericin (BEA) and fusaproliferin (FUS). Samples were extracted with a mixture of acetonitrile:water (85:15, v/v), using an Ultra-Turrax® homogeniser. Mycotoxins were then identified and quantified by liquid chromatography (LC) with diode array detection (DAD). Positive samples were confirmed by LC–MS/MS.     

Exploration of Vanilla pompona from the Peruvian Amazon as a potential source of vanilla essence: Quantification of phenolics by HPLC-DAD

This study provides the first chemical investigation of wild-harvested fruits of Vanilla pompona ssp. grandiflora (Lindl.) Soto-Arenas developed in their natural habitat in the Peruvian Amazon. Flowers were hand-pollinated and the resulting fruits were analysed at different developmental stages using an HPLC-DAD method validated for the quantification of glucovanillin and seven other compounds. The method showed satisfactory linearity (r² > 0.9969), precision (coefficient of variation <2%), recoveries (70–100%), limit of detection (0.008–0.212 μg/ml), and limit of quantification (0.027–0.707 μg/ml). The evaluation of crude and enzyme-hydrolyzed Soxhlet-extracted samples confirmed the leading role of glucosides in fruit development. LC–ESI-MS studies corroborated the identities of four glucosides and seven aglycones, among them vanillin (5.7/100 g), 4-hydroxybenzyl alcohol (3.6/100 g), and anisyl alcohol (7.1/100 g) were found in high concentrations. The attractive flavor/aroma profile exhibited by wild V. pompona fruits supports studies focused on the development of this species as a specialty crop.     

Determination of falcarinol in carrot (Daucus carota L.) genotypes using liquid chromatography/mass spectrometry

A new analytical method for the determination of falcarinol [(Z)-heptadeca-1,9-diene-4,6-diyn-3-ol] in carrot root samples has been developed and validated. The method consists of accelerated solvent extraction (ASE) of lyophilised carrot root samples with ethyl acetate and LC–MS analysis of the extracts. Falcarinol was determined by extracting the main ion species generated in the ESI positive mode, m/z 268 [M+H–H₂O+MeCN]⁺, from the full MS chromatogram. Quantitation was performed using a falcarinol calibration curve (correlation coefficient 0.9975) as an external standard and pelargonic acid vanillylamide as an internal standard. The method showed good precision with interday and intraday variation of less than 4% and high recovery (average recovery rate 97.9%). LOD (S/N = 3) and LOQ (S/N = 10) were 2.5 and 7 ng, respectively. Using this method, 27 different carrot genotypes grown and harvested under the same conditions were analyzed, and falcarinol contents ranging from 0.70 to 4.06 mg/100 g fresh weight were determined.     

The analysis of phenolic constituents in glabrous canaryseed groats

Nineteen glabrous canaryseed samples, comprising brown- and yellow-coloured seeds, were investigated to determine the nature of phenolic constituents present. Total phenolic content (TPC) was determined, using the Folin–Ciocalteau assay. Flavonoid and phenolic acid compositions were determined, using high performance liquid chromatographic and mass spectrometric (LC–MS/MS) techniques. TPC ranged from 174 to 209 mg/100 g for canaryseed wholemeal samples. The canaryseed bran contained twice as much TPC as the wholemeal. The brown- and yellow-coloured whole canaryseeds exhibited the same flavonoid profiles. LC–MS/MS analysis showed that the canaryseed acetone extract was rich in flavonoid glycosides, with the bran being mainly composed of O-pentosyl isovitexin and the flour having a compound at m/z 468. No proanthocyanidins were detected in the 19 samples. Ferulic acid was the dominant phenolic acid, followed by caffeic and p-coumaric acids. The wholemeal obtained from the brown-coloured group had significantly higher contents of ferulic (>196 mg/kg) and caffeic (>96 mg/kg) acids in comparison to the yellow-coloured canaryseed group. The latter had ferulic and caffeic acids at levels less than 165 and 78 mg/kg, respectively, with one exception which had relatively higher levels (190 and 94 mg/kg). Whilst canaryseed flour contained significantly very low levels of ferulic acid (22–34 mg/kg), the bran was enriched in ferulic (593–766 mg/kg), caffeic (304–452 mg/kg) and p-coumaric (119–142 mg/kg) acids.     

Occurrence and sensory perception of Z-2-(β-d-glucopyranosyloxy)-3-phenylpropenoic acid in rooibos (Aspalathus linearis)

Z-2-(β-d-glucopyranosyloxy)-3-phenylpropenoic acid (PPAG), a compound postulated to contribute to the taste and mouthfeel of fermented rooibos tea (Aspalathus linearis), was isolated from unfermented rooibos plant material. Its structure was unequivocally confirmed by LC–MS, –MS², FT-IR and NMR of the underivatised natural product, and optical rotation measurements of the hydrolysed sugar moiety. A similar compound, postulated to be E-2-(β-d-glucopyranosyloxy)-3-phenylpropenoic acid, was also detected. Analysis of the leaves of a large number of rooibos plants (n = 54), sampled at commercial plantations, showed that PPAG is not ubiquitously present in detectable quantities in the leaves of different plants. This leads to large variation in the fermented plant material, infusions and food-grade extracts. PPAG was shown to have a slightly bitter to astringent taste and a detection threshold of 0.4 mg/l in water.     

Simultaneous determination of bisphenol A,octylphenol, and nonylphenol by pressurised liquid extraction and liquid chromatography–tandem mass spectrometry in powdered milk and infant formulas

A new analytical method, using pressurised liquid extraction (PLE) and liquid chromatography–tandem mass spectrometry (LC–MS/MS), was developed for the simultaneous determination of bisphenol A (BPA), octylphenol (OP) and nonylphenol (NP) in powdered infant formulas (IF) and powdered skimmed milk (PM). The analytes were extracted by PLE, using this optimised conditions: ethyl acetate as solvent, 70 °C of temperature, reversed-phase silica C₁₈ as dispersing agent and three cycles of extraction. The extracts were then injected in LC–MS/MS using a Gemini C₁₈ column and a mixture of 5% water and 95% methanol/acetonitrile, both with 0.1% ammonia, as a mobile phase. Recoveries at different fortification levels (0.5 and 0.05 mg kg⁻¹), were between 89% and 92% for BPA, 84 and 98% for OP, and 93% and 101% for NP. The method was applied to the analysis of samples of PM and IF, bought in Italian and Spanish markets. In positive samples, phenols concentration ranged from 0.07 to 1.29 mg kg⁻¹ for BPA, from 0.028 to 1.55 mg kg⁻¹ for OP and from 0.026 to 1.47 mg kg⁻¹ for NP.     

Identification and quantitative determination of glucosinolates in seeds and edible parts of Korean Chinese cabbage

Glucosinolates (GSLs) have attracted major interest due to the chemopreventive properties of some of their transformation products. GSLs in the seeds and edible parts of Korean Chinese cabbage (Brassicacampestris L. ssp. pekinensis) were identified and quantified by LC–ESI–MS and LC–UV. As a result, nine GSLs were identified: progoitrin, glucoraphanin, glucoalyssin, gluconapin, 4-hydroxy-3-indolylmethyl, glucobrassicanapin, glucoerucin, glucobrassicin, and 4-methoxyglucobrassicin. The total GSL levels were 268–198 and 23.0–15.8 μmol/g dry weight (DW) for seeds and edible parts, respectively. Gluconapin (197 μmol/g DW) was the highest individual GSL in seeds, whereas 4-methoxyglucobrassicin (6.08–4.94 μmol/g DW) and glucobrassicanapin (8.18–3.09 μmol/g DW) were found in the edible parts. In addition, LC–MS profiles of the nine GSLs identified from Korean Chinese cabbage were subjected to principal components analysis (PCA) to evaluate differences among samples. The metabolome among the four cultivar seed or edible parts was clearly separated by PCA.     

Isolation and purification of phenylethanoid glycosides from Cistanche deserticola by high-speed counter-current chromatography

Five phenylethanoid glycosides (PhGs), echinacoside, cistanoside A, acteoside, isoacteoside and 2′-acetylacteoside, were isolated and purified from Cistanche deserticola for the first time by high-speed counter-current chromatography (HSCCC) using two biphasic systems, one consisting of ethyl acetate–ethanol–water (5:0.5:4.5, v/v/v) and another of ethyl acetate–n-butanol–ethanol–water (0.5:0.5:0.1:1, v/v/v/v). A total of 28.5 mg of echinacoside, 18.4 mg of cistanoside A, 14.6 mg of acteoside, 30.1 mg of isoacteoside and 25.2 mg of 2′-acetylacteoside were purified from 1412 mg of the n-butanol extract of C. deserticola, each at over 92.5% purity as determined by HPLC. The structures were identified by their retention time, UV, LC–ESI-MS in the negative ion mode, and confirmed by NMR experiments. The characteristic LC–ESI-MSⁿ fragmentation pattern of the five compounds is discussed, and found to be a very specific and useful tool for the structural identification of PhGs from this important medicinal plant.     

Interference-free determination of acrylamide in potato and cereal-based foods by a laboratory validated liquid chromatography–mass spectrometry method

A simple and rapid method was developed and validated for the determination of acrylamide in potato and cereal-based foods by using a single quadrupole liquid chromatography–mass spectrometry (LC–MS) interfaced with positive atmospheric pressure chemical ionization (APCI+). Acrylamide was simply extracted with 0.01 mM acetic acid in a vortex mixer prior to LC–MS analysis. The applicability of validated method was shown for a wide range of processed foods including chips, fries, crisps, breads, biscuits and cookies. The mean recovery was found to be 99.7 with a repeatability of 1.8% in the range 100–1000 ng/g. During LC–MS analyses, the major interfering co-extractive was identified as valine which yields characteristic [M + H]⁺ and compound specific product ions having m/z of 118 and 72, respectively. Valine increased the baseline signal preventing accurate and precise quantitation, and resulted in poorer sensitivity in selected ion monitoring mode. The adverse effect of valine could be limited by instrumentally adjusted delay time or by solid-phase extraction with strong cation-exchanger sorbent.     

Sterigmatocystin presence in typical Latvian grains

Ninety five samples of different Latvian grains (wheat, buckwheat, barley, oats and rye) from the year 2006 and 120 samples from the year 2007 were analyzed for Aspergillus ssp. mycotoxin–sterigmatocystin (STC) content. 13.7% of the analyzed 2006 year samples were positive for STC with the concentration levels ranging from <0.7 to 83 μg/kg and 35% of the analyzed 2007 year samples were positive for STC with the concentration levels ranging from <1 to 47 μg/kg. A previously developed sensitive LC – Electrospray Positive Ionization – MS/MS method was applied for the analysis of STC in grains. Method includes sample extraction with acetonitrile/water solution, solid phase extraction (SPE) on Strata X SPE column, separation on reversed phase C₁₈ column and STC detection by LC–MS/MS.     

Determination of tetracyclines in multi-specie animal tissues by pressurized liquid extraction and liquid chromatography–tandem mass spectrometry

A specific, sensitive and robust pressurized liquid extraction (PLE) and liquid chromatography tandem mass spectrometry (LC–MS/MS) method for determining tetracycline, chlortetracycline, oxytetracycline and doxycycline in bovine, swine, poultry and lamb muscle tissues is presented. PLE was performed using an ASE^® 200 from Dionex and water as extractant, followed by solid-phase extraction (SPE) using an Oasis HLB cartridge. The method was validated for beef, chicken, pork and lamb meat in compliance with the requirements set by Commission Decision, 2002/657/EC [Commission Decision 2002/657/EC (2002). Implementing Council Directive 96/23/EC concerning the performance of analytical methods and interpretation of results. Official Journal of European Communities, L239, 66–98. (Available at: <http://europe.eu.int>)]. The average recoveries of the different meat samples, spiked with the four tetracyclines at three levels (1, 100 and 200 μg kg⁻¹ of each tetracycline), were always higher than 89% with intraday and interday precision lower than 15% and 17%, respectively. A good linearity was established for the four tetracyclines in the range from 5 to 10,000 μg kg⁻¹ with r > 0.995. The limits of quantification (LOQs) were between 0.5 and 1 μg kg⁻¹, which are well below the tolerance levels set by the European Union. The decision limit (CCα) and the decision capability (CCβ) were in the range 101–116 and 112–130 μg kg⁻¹, respectively. Compared with previous methods, sample preparation time required for the analysis and LOQs, are reduced. The method demonstrated its successful application for the analysis of 100 meat samples. Two samples of beef and one sample of chicken out of 25 of each type tested positive while none of 25 samples of either, lamb or pork, tested positive.     

Determination of aflatoxin levels in nuts and their products consumed in South Korea

A total of 85 nuts and their products marketed in South Korea were assessed for aflatoxins using a monitoring scheme consisting of enzyme-linked immunosorbent assay (ELISA) for rapid screening, high performance liquid chromatography (HPLC) for quantification and LC–mass spectrometry (MS) for confirmation. Thirty-one out of 85 samples gave ELISA readings above 0.06 and were screened as possible positive samples. Aflatoxin contents of possible positive samples were determined using HPLC with a detection limit of 0.08–1.25 μg/kg and a quantification limit of 0.15–2.50 μg/kg. Nine samples including 1 raw peanut, 4 roasted peanuts, 2 peanut butters, 1 pistachio and 1 seasoned assorted nut were contaminated with aflatoxins (10.6% of incidence), ranging in various levels up to 28.2 μg/kg. LC–MS analysis on contaminated samples revealed that peaks eluting at 4.4, 5.2, 9.1 and 11.9 min were confirmed as aflatoxin G₁, aflatoxin B₁, aflatoxin G₂ and aflatoxin B₂, respectively.     

Quantitative analysis of acrylamide in tea by liquid chromatography coupled with electrospray ionization tandem mass spectrometry

An effective sample preparation procedure was optimized and a liquid chromatography–tandem mass spectrometry (LC–MS/MS) was developed for the quantitative analysis of acrylamide in tea. [¹³C₃]-acrylamide was used as internal standard. Acrylamide was extracted at 25 °C for 20 min by 10 ml water followed by 10 ml acetonitrile, and then 4 g of magnesium sulfate and 0.5 g of sodium chloride were added to the above mixture under stirring thoroughly. In order to increase the response of acrylamide, 9 ml acetonitrile layer was taken and concentrated to 0.5 ml. Solid-phase extraction with an Oasis MCX cartridge was carried out for clean-up. The limit of detection (LOD) and limit of quantification (LOQ) were 1 and 5 ng/ml, respectively. The recovery efficiency of the extraction procedure ranged between 74% and 79%. The levels of acrylamide in 30 tea samples were less than 100 ng/g. Black, oolong, white and yellow tea samples had quite low acrylamide contents (<20 ng/g). Higher acrylamide levels occurred in baked, roasted, and one sun-dried green tea samples (46–94 ng/g).     

Analyses of selected non-authorized insecticides in peppers by gas chromatography/mass spectrometry and gas chromatography/tandem mass spectrometry

Two methods based on gas chromatography coupled with mass spectrometry and tandem mass spectrometry analyzers are described for the identification, confirmation and quantitation of two EU-banned insecticides: isocarbophos and isofenphos-methyl, detected in recent monitoring programmes in pepper samples. The proposed methodologies involved a liquid–liquid extraction with acetonitrile followed by a cleanup step by dispersive solid-phase extraction using primary–secondary amine as sorbent material. Recovery studies performed on peppers spiked at different fortification levels (10 and 50 μg kg⁻¹) yielded average recoveries in the range 85–98% with RSD values below 8%. Identification, confirmation and quantitation were carried out by gas chromatography/mass spectrometry (GC–MS) in selected ion monitoring mode and gas chromatography/tandem mass spectrometry (GC–MS/MS) using an ion trap operating in the multiple reaction monitoring (MRM) mode. The obtained limits of detection (LODs) were in the range 0.1–0.3 μg kg⁻¹, depending on the technique. The proposed methods were successfully applied to the analysis of suspected pepper samples.     

Dissipation kinetics of forchlorfenuron, 6-benzyl aminopurine,gibberellic acid and ethephon residues in table grapes (Vitis vinifera)

The residue dynamics of plant growth regulators (PGR) forchlorfenuron (CPPU), 6-benzylaminopurine (6-BA), gibberellic acid (GA₃) and ethephon in grape are presented, corresponding to their field applications at recommended and double doses. Random samples were collected from each treated and control plot at regular time intervals. The optimised sample preparation technique involves extraction of 10 g homogenised sample with 20 ml methanol (+1% formic acid) and measurement by LC–MS/MS multiple reaction monitoring, offering limit of quantification ?0.0025 μg/g for all except ethephon with LOQ of 0.005 μg/g. The recoveries at LOQ and above were 84.8–109.5%. Residue dissipation of all the PGRs followed non-linear two-compartment first + first-order kinetics. CPPU, 6-BA and ethephon residues dissipated with preharvest intervals (PHIs) of 33.5, 12 and 32 days at recommended dose with no PHI applicable for GA₃. The PHIs successfully minimised residue problems as observed from survey results of traceable field samples.