Development of a Modified QuEChERS Method Coupled with LC-MS/MS for Determination of Spinetoram Residue in Soybean (Glycine max) and Cotton (Gossypium hirsutum)

An analytical method for the quantitative determination of the insecticide spinetoram in cotton and soybean was established and validated using liquid chromatography tandem mass spectrometry (LC-MS/MS). Spinetoram is the mixture of two spinosyns, 3′-O-ethyl-5,6-dihydro spinosyn J and 3′-O-ethyl spinosyn L. The method involves extraction with ethyl acetate followed by dispersive solid phase extraction (dSPE) clean-up with primary secondary amine (PSA), C18 and graphitised carbon black (GCB). The final quantitation of spinetoram was done by using LC-MS/MS with positive electrospray ionization. The method was reproducible (Horwitz ratio (HorRat) < 0.5 at 25 ng g−1) and validated by the analysis of samples spiked at 25, 50 and 100 ng g−1 in soybean, cotton and soil. The recoveries of spinosyns were found to be more than 85% when spiked at different levels. The identities of spinosyns were confirmed by using the ion ratio. A field dissipation study was conducted in soybean and cotton to find out the environmental fate of spinetoram, and samples were analysed following the proposed analytical method. Both isomers were found to be dissipated quickly. The pre-harvest interval of spinetoram was calculated in different substrates.

Analysis of aflatoxins and ochratoxin a in chilli powder using ultrahigh performance liquid chromatography with fluorescence detection and tandem mass spectrometry

Chilli powder, a popular spice, is predominantly contaminated with aflatoxins (AFs) and ochratoxin A (OTA), posing a menace to public health. As no validated method exists for the simultaneous and direct analysis of AFs and OTA in chilli powder, it was imperative to develop one to ensure their effective monitoring and promote trade. In this research, we developed and validated a multi-mycotoxin analysis method that allows the simultaneous determination of AFs (AFB₁, AFB₂, AFG₁ and AFG₂) and OTA in chilli powder with high sensitivity, accuracy and precision. The optimised sample preparation workflow started with the extraction of chilli powder (25 g) with methanol-water (100 mL, 80:20). An aliquot (3 mL) was cleaned on a multi-mycotoxin, immunoaffinity column (AFLAOCHRA PREP^®) and analysed using ultrahigh performance liquid chromatography with fluorescence (UHPLC-FLD) and tandem mass spectrometric (LC-MS/MS) detection in a single chromatographic run. The method performance was evaluated through intra- and inter-laboratory validation (ILV) studies, and also by analysing a certified reference material. A direct analysis using UHPLC-FLD (without derivatisation) provided the limits of quantification (LOQ) of 0.25 and 1 ng/g for AFs and OTA, respectively, while the LOQ for all these mycotoxins in LC-MS/MS was 0.5 ng/g. These LOQs are much lower than the maximum levels (MLs) specified by the European Commission. The recoveries of these analytes at LOQ and higher levels were above 75% (RSD_r < 12%). The ILV study demonstrated satisfactory method-reproducibility (RSD_R < 25%). The analysis of the certified reference material provided accuracies of AFs and OTA in the range of 83-101%. The analysis by UHPLC-FLD and LC-MS/MS provided very similar results. The incurred levels of B1 in market samples were estimated with a precision-RSD of < 6%. Considering its efficiency and alignment with the regulatory requirements, this method can be implemented for the routine analysis of AFs and OTA in chilli powder.

Persistence behaviour and safety risk evaluation of pyridalyl in tomato and cabbage

A field experiment was set up to evaluate persistence behaviour of pyridalyl in tomato, cabbage and cultivated field soil over two consecutive seasons. An analytical method was developed to analyze pyridalyl residues in different matrices and duly validated, based on single laboratory method validation criteria. Pyridalyl residues were detected and quantified using a gas chromatograph equipped with an electron capture detector. The compound exhibited low persistence in tomato, cabbage and soil. A safe waiting period of 17-18 d after final insecticide application needs to be maintained before harvesting the crop. Both dietary and soil ecological risk were assessed and it was found that the harvested vegetables were toxicologically safe for consumption. However, there was concern about insecticidal toxicity against the algal population of soil which needs to be reconfirmed by further studies.

Chemo-profiling of anthocyanins and fatty acids present in pomegranate aril and seed grown in Indian condition and its bioaccessibility study

The goal of the present study was to investigate the bioactive molecules (anthocyanins and fatty acids) present in the aril of pomegranate. Major anthocyanins present in the aril of pomegranate were identified by HRMS as delphinidin 3,5-diglucoside, cyanidin 3,5-diglucoside, pelargonidin 3,5-diglucoside, cyanidin 3-glucoside and delphinidin 3-glucoside. In-vitro study revealed that bioaccessibility of anthocyanin in duodenal condition was varied between 7.3 and 9.7%. Encapsulation enhances the bioaccessibility of both the phenolics to some extent in gastric as well as duodenal condition. Seed oil contains significant amount of unsaturated fatty acids especially ω-5 fatty acids. Geometrical isomers of ω-5 fatty acids were also identified by GC-MS. The spray dried anthocyanin formulation has potential for food application.

High-sensitivity direct analysis of aflatoxins in peanuts and cereal matrices by ultra-performance liquid chromatography with fluorescence detection involving a large volume flow cell

This paper reports a sensitive and cost effective method of analysis for aflatoxins B1, B2, G1 and G2. The sample preparation method was primarily optimised in peanuts, followed by its validation in a range of peanut-processed products and cereal (rice, corn, millets) matrices. Peanut slurry [12.5 g peanut + 12.5 mL water] was extracted with methanol: water (8:2, 100 mL), cleaned through an immunoaffinity column and thereafter measured directly by ultra-performance liquid chromatography-fluorescence (UPLC-FLD) detection, within a chromatographic runtime of 5 minutes. The use of a large volume flow cell in the FLD nullified the requirement of any post-column derivatisation and provided the lowest ever reported limits of quantification of 0.025 for B1 and G1 and 0.01 μg/kg for B2 and G2. The single laboratory validation of the method provided acceptable selectivity, linearity, recovery and precision for reliable quantifications in all the test matrices as well as demonstrated compliance with the EC 401/2006 guidelines for analytical quality control of aflatoxins in foodstuffs.

Persistence behavior of metamifop and its metabolite in rice ecosystem

A field experiment was conducted to determine the persistence of metamifop in transplanted rice crop for two seasons. Metamifop 10% EC was applied at two doses: 100 g a.i. ha^-1 and 200 g a.i. ha^-1 at 2-3 leaf stage of Echinochloa crusgalli. The residues of metamifop along with its major metabolite, N-(2-fluorophenyl)-2-hydroxy-N-methylpropionamide (HFMPA), were estimated in rice plant, field water and soil using Liquid Chromatography Mass Spectrometry. Limit of detection and limit of quantification of the method for both the compounds were set at 0.003 μg g^-1 and 0.010 μg g^-1 respectively. Metamifop showed less persistence in field water and rice plant as compared to soil samples. Presence of HFMPA was recorded in rice plant and soil. Both the compounds were found below level of quantification in harvest samples of straw, grains, husk and soil. A safe waiting period of 52 d was suggested for harvesting of rice when metamifop was applied at 100 g a.i. ha^-1 (recommended dose).

Optimization and Validation of a Residue Analysis Method for Glyphosate, Glufosinate, and Their Metabolites in Plant Matrixes by Liquid Chromatography with Tandem Mass Spectrometry

A sensitive and accurate LC with tandem MS (MS/MS)-based method was developed and validated for the analysis of the herbicide glyphosate, its metabolite aminomethylphosphonic acid (AMPA), and glufosinate after derivatization with 9-fluorenylmethyl chloroformate (FMOC-Cl) in various plant matrixes. The method also covers direct analysis of the glufosinate metabolites 3-methylphosphinicopropionic acid (3-MPPA) and N-acetyl-glufosinate (NAG). The homogenized samples were extracted with 0.1% formic acid in water-dichloromethane (50 + 50). The aqueous layer was derivatized with FMOC-Cl, cleaned through an HLB SPE cartridge, and determined by LC-MS/MS. The sample size, extraction solvent, sample-to-solvent ratio, derivatization conditions, and cleanup procedure were thoroughly optimized, the LOQs of glyphosate, glufosinate, and AMPA were 0.5 ng/g in grape, corn (leaf and seed), and cotton (leaf, seed, and oil) and 2 ng/g in soybean and tea. The LOQs of NAG and 3-MPPA were 50 ng/g in all the test matrixes, except tea and soybean, for which the LOQ was 100 ng/g. In all cases, average recoveries were >80%. The method successfully performed the estimation of glyphosate in incurred corn and cotton leaf samples collected from supervised field trials.

Persistence behaviour of fungicide tebuconazole in a viticulture application

Dissipation pattern and risk assessment of tebuconazole in grapes was studied following two application rates (250 and 500 mL ha(-1)) under tropical humid climatic condition of West Bengal during 2009-2010. Residues of tebuconazole were confirmed by liquid chromatography-mass spectrometry. The average recoveries were found 87.53 % and 89.67 % for grapes and cropped soil respectively. Following the first order kinetics the fungicide dissipates in grapes with a half-life (T1/2) value ranges between 2.62 and 2.86 days irrespective of seasons and doses. No residues of tebuconazole were detected in harvest grapes and soil samples which refers that, tebuconazole does not possess any background contamination property in grapes. So it may be concluded from the study that tebuconazole does not possess any toxicological property when applied at the recommended dose.

Persistence behaviour of fungicide mixture (benalaxyl-M 4% + mancozeb 65%) WP in grapes

Benalaxyl-M [methyl N-phenylacetyl-N-2, 6-xylyl-DL-alaninate] is a newly introduced phenyl-amide fungicide whereas Mancozeb is one of the member of ethylenebisdiothiocarbamate (EBDC) fungicide. Benalaxyl-M in combination with Mancozeb effectively controls downy mildew of grapes. A two season field trial was conducted under West Bengal climatic condition during 2009-2010 to evaluate the dissipation pattern of fungicide mixture (Benalaxyl-M 4 % + Mancozeb 65 %) WP in grapes at two application rates (2,750 g and 5,500 g ha(-1)). The quantitative analysis was performed using liquid chromatography-mass spectrometry (LC-MS/MS) and UV-Vis spectrophotometer for Benalaxyl-M and Mancozeb residues respectively. Following the first order kinetics the fungicide Benalaxyl-M dissipates in grapes with half-life (T(1/2)) value ranges between 2.59 and 2.79 days irrespective of seasons and doses. The dissipation pattern of Mancozeb also follows first order kinetics with half-life (T(1/2)) value ranges between 3.86 and 4.93 days irrespective of seasons and doses.

Atopy patch testing with aeroallergens in patients with atopic dermatitis and controls in Singapore

The role of allergy in atopic dermatitis is controversial. The atopy patch test (APT) has been used to investigate the association between atopic dermatitis and aeroallergen allergy. To determine the proportion of patients with atopic dermatitis with positive patch tests to common local aeroallergens and to compare this to controls with and without respiratory atopy, we performed APT, skin-prick tests (SPT) and IgE radioallergosorbent tests (RAST) on 73 patients with atopic dermatitis and on 38 nonatopic controls (13 with and 25 without respiratory atopy). The allergens used were house dust mite, cat dander, Bermuda grass and German cockroach. Only the APT for house dust mite showed a significant difference between the two groups. APT for house dust mite correlated with the RAST test, while APT for cat fur correlated with the SPT. The APT may be useful to evaluate aeroallergens in atopic dermatitis, but further work is needed to make it more reliable.

A comparison of the combined effect of cryotherapy and corticosteroid injections versus corticosteroids and cryotherapy alone on keloids: a controlled study

BACKGROUND

Treatment modalities for keloids, which are commonly found in Asians, include intralesional corticosteroid injections and cryotherapy as well as a combination of these two modalities. Few studies have been performed in a controlled fashion to evaluate the efficacy of these treatments.

OBJECTIVE

A controlled study, to evaluate the combined effect of intralesional corticosteroid injection with cryotherapy vs. intralesional corticosteroid or cryotherapy alone.

METHODS

Ten patients completed the study: eight patients had at least three keloids and two had two keloids. Patients were treated for at least three sessions 4 weeks apart. The outcome of the lesions was compared between the treatments regarding the thickness of the lesion using a caliper and photographic assessment, and the presence of itch and pain before and after treatment using a visual analogue scale.

RESULTS

In terms of thickness, the keloids responded significantly better to combined cryotherapy and triamcinolone vs. triamcinolone alone or cryotherapy alone (P < 0.001). Pain intensity was significantly lowered with all treatment modalities; however, itch was lowered only with the combined treatment and intralesional corticosteroid alone. No significant side effects were noted with any of the treatments and no re-occurrence of keloids was noted with the combined therapy.

CONCLUSION

Combined injection of intralesional steroids with cryotherapy appears to be superior to other current modalities.

Clinical characteristics of pruritus in chronic idiopathic urticaria

BACKGROUND

Although pruritus is a predominant symptom of chronic idiopathic urticaria (CIU) its clinical characteristics have not been explored.

OBJECTIVES

To characterize the clinical pattern and sensory and affective dimensions of the itch experience, utilizing a comprehensive itch questionnaire.

METHODS

A structured questionnaire based on the McGill pain questionnaire was used in 100 patients suffering from CIU randomly recruited from a tertiary referral centre.

RESULTS

All 100 patients recruited with CIU completed the questionnaire. In 68 patients pruritus appeared on a daily basis. Most patients experienced their pruritus at night and in the evening (n = 83), and 62 reported difficulty in falling asleep. Pruritus involved all body areas, but mostly the arms (n = 86), back (n = 78) and legs (n = 75). Accompanying symptoms were a sensation of heat in 45 patients and sweating in 15. Most patients (n = 98) were prescribed antihistamines (mainly sedating), of whom 34 experienced long-term relief. The sensation of itch was reported to be stinging (n = 27), tickling (n = 25) and burning (n = 23). Seventy-six patients found their pruritus bothersome, 66 annoying and 14 complained of depression. The itch intensity at its peak was more than double that felt after a mosquito bite. The worst itch scores of those who felt depressed were significantly higher than of those who did not (P = 0.018). There was a positive correlation between the sensory and affective scores during worst itch (P < 0.001).

CONCLUSIONS

This study describes the itch experienced in CIU, highlighting sensory and affective dimensions. The itch questionnaire was found to be a valuable tool for evaluating pruritus in CIU and its unique features.

The effect of topically applied aspirin on localized circumscribed neurodermatitis

BACKGROUND

Lichen simplex chronicus is a troublesome intractable itchy dermatosis, which may persist despite intensive topical treatments. Recently it has been demonstrated that topical aspirin solution with dichloromethane has a significant antipruritic effect in an experimentally induced itch.

OBJECTIVE

The aim of this double-blind, crossover placebo trial was to evaluate the efficacy of this solution in the treatment of lichen simplex chronicus.

METHODS

Twenty-nine patients with lichen simplex chronicus of at least 3 months' duration that did not respond to topical corticosteroids were randomized in a double-blind fashion to receive aspirin/dichloromethane solution in treatment period 1 for 2 weeks followed by placebo in treatment period 2 or placebo followed by aspirin in period 2 with a crossover design after a 2-week washout. The patients rated the pruritus intensity before and during therapy with a visual analog scale; a blinded investigator performed photographic assessment.

RESULTS

A significant therapeutic response was achieved in 11 (46%) of the patients who completed the study compared with 3 patients (12%) receiving placebo. Overall, aspirin-treated patients experienced an average decrease in the visual analog scale of 2.18 +/- 2.86 versus 0.69 +/- 2.31 of those receiving placebo. The difference between the 2 treatments for week 2 was significant (P =.03).

CONCLUSION

The study suggests that topical aspirin/dichloromethane might be a practical treatment for lichen simplex chronicus.

The prevalence and clinical characteristics of pruritus among patients with extensive psoriasis

BACKGROUND

Many patients with psoriasis are known to suffer from itch. However, the data available regarding itch and its characteristics in psoriasis are sparse.

OBJECTIVES

To examine the prevalence of pruritus and various related clinical characteristics in 101 patients with extensive psoriasis.

METHODS

A structured questionnaire was used.

RESULTS

Generalized pruritus was a feature of psoriasis in 84% of the patients. In 77% of these it appeared on a daily basis. It involved all areas of the body, had prolonged duration and appeared mainly in the evening and at night. The pruritus significantly affected quality of life. Important daily factors that were found to exacerbate the itch were ambient heat (81%), skin dryness (80%), sweating (65%) and stress (55%). Important factors that were found to ameliorate itch were sleep (57%) and cold showers (55%). The pruritus was found to be unresponsive to most available antipruritics, including phototherapy. Itch intensity as reflected by a visual analogue scale did not correlate with Psoriasis Area and Severity Index scores; however, a highly significant correlation was obtained between the affective descriptors and itch intensity in the worst itch states (r = 0.6, P < 0.001).

CONCLUSIONS

Pruritus is a common feature of psoriasis and affects quality of life.

Multifocal planes head-mounted displays

Stereoscopic head-mounted displays (HMD's) provide an effective capability to create dynamic virtual environments. For a user of such environments, virtual objects would be displayed ideally at the appropriate distances, and natural concordant accommodation and convergence would be provided. Under such image display conditions, the user perceives these objects as if they were objects in a real environment. Current HMD technology requires convergent eye movements. However, it is currently limited by fixed visual accommodation, which is inconsistent with real-world vision. A prototype multiplanar volumetric projection display based on a stack of laminated planes was built for medical visualization as discussed in a paper presented at a 1999 Advanced Research Projects Agency workshop (Sullivan, Advanced Research Projects Agency, Arlington, Va., 1999). We show how such technology can be engineered to create a set of virtual planes appropriately configured in visual space to suppress conflicts of convergence and accommodation in HMD's. Although some scanning mechanism could be employed to create a set of desirable planes from a two-dimensional conventional display, multiplanar technology accomplishes such function with no moving parts. Based on optical principles and human vision, we present a comprehensive investigation of the engineering specification of multiplanar technology for integration in HMD's. Using selected human visual acuity and stereoacuity criteria, we show that the display requires at most 27 equally spaced planes, which is within the capability of current research and development display devices, located within a maximal 26-mm-wide stack. We further show that the necessary in-plane resolution is of the order of 5 microm.

Efficacy of hypocaloric total parenteral nutrition in hospitalized obese patients: a prospective, double-blind randomized trial

Obesity is a major health problem in the United States today. Traditionally, management of obese hospitalized patients has not differed from that of normal-weight patients, with calorie and protein needs based on current body weight and weight loss postponed until the acute illness has subsided. This study was undertaken to determine whether obese hospitalized patients (> 130% ideal body weight) requiring total parenteral nutrition and given hypocaloric (HC) feedings with adequate protein intake could achieve nitrogen balance comparable with that of controls (C) given isonitrogenous normocaloric formulas. Sixteen obese patients (HC = 9, C = 7) were randomized to either HC (50% resting metabolic energy expenditure, plus protein; calories:nitrogen = 75:1) or C (100% resting metabolic energy expenditure, plus protein; calories:nitrogen = 150:1) formulas. Resting metabolic energy expenditure was determined by indirect calorimetry on day 0 and weekly, and nitrogen balance was determined daily. The two groups were similar in Harris-Benedict predicted energy expenditure and metabolic energy expenditure, initial and final serum albumin, total iron-binding capacity, and weight loss. Total daily calorie and nonprotein calorie intake per kilogram body weight were 14 +/- 4.1 (HC) vs 25 +/- 4 (C) and 7 +/- 1.9 (HC) vs 20 +/- 3 (C), respectively. Protein intake was 1.23 +/- 0.4 (HC) vs 1.31 +/- 0.2 (C) g/kg per day. Initial respiratory quotients were similar and consistent with fasting (HC = 0.7 +/- 0.09 vs C = 0.66 +/- 0.09); final respiratory quotients in C patients reflected mixed fuel use (C = 0.82 +/- 0.11 vs HC = 0.7 +/- 0.12).(ABSTRACT TRUNCATED AT 250 WORDS)