Daminozide Residues Research Articles

Determination of daminozide residues in apple pulp using HPLC-DAD-UV.

This paper reports an HPLC-UV method to determine daminozide residues in apple pulps adopting the recently introduced EU limit of 0.01 mg/kg for baby food preparation (Commission Directive 1999/39/CE). The method is based on alkaline hydrolysis of daminozide to N',N'-dimethylhydrazine (UDMH), which is recovered by distillation and subsequently derivatizated with salicyl aldehyde to salicyl aldehyde-N,N-dimethylhydrazone under strongly basic conditions. The resulting solution was cleaned up with Extrelut 20 NT and dichloromethane as eluent, then analyzed by HPLC with a C18 column and a mobile phase programmed from 50:50 AcCN/H(2)O to 100% AcCN. The salicyl aldehyde-N,N-dimethylhydrazone was selectively detected through two diagnostic UV absorption maxima at 295 and 325 nm, which have strong molar absorbivities. Recoveries of daminozide at 0.01 mg/kg were above 80%. The limits of detection (LODs) of salicyl aldehyde-N,N-dimethylhydrazone expressed as daminozide concentration were 100 pg/microL at 295 nm and 150 pg/microL at 325 nm, and the limits of quantitation (LOQs) of daminozide were 0.0013 mg/kg at 295 nm and 0.0022 mg/kg at 325 nm.

Determination of daminozide residues in apples using gas chromatography with nitrogen-phosphorus detection

A method was developed for the determination of daminozide in apples using gas chromatography (GC) with nitrogen-phosphorus detection (NPD). Daminozide is hydrolysed to 1,1-dimethylhydrazine (UDMH) by alkaline digestion. The UDMH generated is distilled from the apple matrix, derivatized with 2-nitrobenzaldehyde and analysed by GC-NPD. The limit of detection (LOD) and the limit of quantitation (LOQ) for daminozide are 1.9 μg/kg and 6.2 μg/kg, respectively, in a 10-g sample. Average recoveries from apples spiked at the 12 and 60 μg/kg level are between 88% and 108% with R.S.D.s ⩽6.9%. Additives used by others, such as calcium chloride, titanium chloride or zinc, have no positive effect on the extraction of daminozide from samples with incurred residues. The repeatability for these samples, containing 0.018, 0.13 and 1.8 mg/kg daminozide, is 4.0%, 4.4% and 2.5%, respectively.

Determination of Daminozide Residues at Very Low Levels in Fruits by Gas Chromatography/Mass Spectrometry

Determination of Daminozide Residues at Very Low Levels in Fruits by Gas Chromatography/Mass Spectrometry

The Decomposition of Daminozide (Alar) to Form Unsymmetrical Dimethylhydrazine (UDMH) in Heated, pH Adjusted, Canned Solutions

Processing conditions were chosen to determine the influence of temperature, pH, and processing on model solutions containing daminozide residues. Daminozide (succinamic acid 2, 2-dimethylhydrazide) fortified solutions (12.5 ppm) containing 50mM NaH2PO4 and 24% sucrose (w/w) were adjusted to pH 3.0, 3.6, or 4.0 and either heated (100°C) for 0, 5, 10, or 15 min in sealed cans and cooled or heated (80°C) for 0, 5, or 10 min in open cans, sealed, heated (100°C) for 5 min, and cooled. Daminozide degradation due to heating was less than the HPLC detection limit (1.5 ppm) for all of the treatments. Unsymmetrical dimethylhydrazine (UDMH) concentration was significantly affected by heating time, pH, and processing. Heating of daminozide solutions in sealed cans produced approximately 1 ppm of UDMH for every minute of heating at 100°C. Heating of daminozide solutions in open cans at 80°C resulted in simultaneous production of UDMH in the solution and loss of UDMH through volatilization. Maximum degradation of daminozide was observed at pH 3.6.

DAMINOZIDE RESIDUE PRESENT IN APPLE FRUIT AFTER LONG AND SHORT TERM EXPOSURE

ABSTRACTDaminozide residues were determined in ppm or ppb on ‘Starking', ‘Red King', ‘Rome’and ‘Golden Delicious’apples after repeated long term exposure (21 years) and on ‘Top Red’apples after short term (1 year) exposure. Application rates varied from 2.2 to 9.0 kg/ha for short term exposure and 2.2 to 4.5 kg/ha for long term exposure. Two and three years after cessation of the daminozide spray program no daminozide residues were found in ‘Top Red’regardless of the rate applied or analytical procedure used. Daminozide residues (<1 ppm) were present in ‘Starking', ‘Red King', ‘Rome’and ‘Golden Delicious’one year after cessation of the spray program. The cultivar ‘Rome’had consistently higher daminozide residue levels followed by ‘Golden Delicious', ‘Red King’and ‘Starking'.

Daminozide residues in apple orchards: Concentrations in fruit, trees, and soil

In the Spring of 1989 considerable public attention was focussed on daminozide (Alar n) residues found in apple products. Daminozide is manufactured by the Uniroyal Chemical Company (Naugatuck, CT) and is used as a growth retardant on fruit trees, peanut vines, and ornamental plants, and to a lesser extent on tomatoes, grapes, and brussels sprouts. In apple orchards it is applied as a foliar spray from mid-July to mid-August to improve color development in red varieties and to maintain quality during the cold storage of all apple varieties. One objective of the current study is the determination of carry-over levels of daminozide in apple orchards from one growing season to the next. We sought to determine if daminozide lingers as a xenobiotic when the chemical is used in normal agricultural practice rather than in carefully controlled studies. Previous field studies of daminozide residues in apple trees were carried out at well-regulated application levels

Determination of Daminozide in Apples by Gas Chromatography /Chemical Ionization Mass Spectrometry

A method using gas chromatography/chemical ionization mass spectrometry (GC/CIMS) for the determination of daminozide residues in apples has been developed. Daminozide was separated from the sample matrix by water extraction and cation exchange, converted to the methyl ester by treatment with HCl-methanol, and determined by GC/CIMS using succinonitrile as an internal standard. The detection level was 0.05 ppm. Recoveries were 92-104% from apples spiked at the 0.05-0.5 ppm levels. Of the 25 apple samples analyzed, only 2 were positive for daminozide (1.04 and 0.32 ppm).

RESPONSE OF ‘TOP RED DELICIOUS’ APPLES TO DAMINOZIDE

ABSTRACTDaminozide was applied at 2.2, 4.5, 6.7 or 9.0 kg/ha to ‘Top Red Delicious’ apple trees 86 days after full bloom the first year and at 2.2, 3.4 or 4.5 kg/ha, 80 days after full bloom the second year. At commercial harvest, after 2 and 4 months regular cold storage, and after 6 and 10 months of controlled atmosphere (CA) storage apples were evaluated for carbon dioxide, ethylene production, flesh firmness, external color, soluble solids, acids, subjective appearance and daminozide residue. Ethylene production was reduced as daminozide application was increased. Delay in onset of the climacteric ranged from 3 to 21 days depending on chemical rate used. Firmness, red color, acids, subjective appearance and number of days to reach climacteric were significantly improved by all rates of daminozide. Quality differences due to daminozide were evident following both types of storage. Daminozide residues were directly related to rate and did not dissipate during storage. There was no detectable daminozide carry‐over in fruit from year to year.

Residue Levels of Daminozide in Apple Trees Sprayed the Preceding Spring and Summer

Daminozide residue levels in fruit and vegetative parts of apple trees were determined the year following foliar spray treatments with daminozide at recommended rates and times and at excessive rates and times closer to harvest than recommended. Trees were sampled in December, March and August following spraying. Daminozide residues were found in all vegetative plant parts, with the highest residue levels found in the buds, bark and xylem of spurs, and in terminal and lateral buds; the lowest residue levels were found in the bark and xylem of stems. Residue levels were affected by both rate and time of application. Residue levels increased as application rates increased, but the response to rate was less when treatments were applied 21 d after bloom (125 d before harvest) than when treatments were applied closer to harvest. The highest residue levels were from treatments applied the day of harvest. Higher residue levels were found in March samples than December samples. Residues had been dissipated to low levels by the August sampling date. No daminozide residues were found in apple fruit from trees treated the previous year with recommended levels of daminozide applied at the recommended time. However, low residue levels were found in fruit treated with 2 × and 4 × rates of daminozide at times closer to harvest than recommended.

Daminozide and Unsymmetrical Dimethylhydrazine(UDMH) Residues in Fresh and Processed ‘Red Delicious’ Apples

Daminozide is a growth regulating substance widely used on apples and other fruit crops to affect various fruit and tree characteristics. Daminozide residues were determined in ‘Starkrimson’ Red Delicious apples orchard-sprayed at both recommended and excessive rates, at recommended periods before expected harvest, and at several application times closer to harvest than recommended. Analyses were conducted on the whole raw fruit, including the peeling, and on applesauce processed from the peeled and cored fruit, immediately after harvest, and after cold storage periods of 30, 60 and 90 d. Residues in both the fresh and processed fruit were directly proportional to the concentration of daminozide in the foliar sprays, regardless of application date. The highest residues in both fresh and processed apples were in fruit from trees sprayed 14 to 28 d before harvest at all spray concentrations. Residues from all spray concentrations and all application dates were persistent for 90 d at 0°C storage for fresh fruit and at 23°C storage for processed fruit. Only the residues in fruit sprayed with four times the recommended level at 2 or 4 wk before harvest exceeded the U.S. Environmental Protection Agency tolerance level (30 ppm). Residues ranged from <2 to 32 ppm. Unsymmetrical dimethylhydrazine (UDMH) levels were directly proportional to the daminozide residues in the applesauce. Average UDMH residues ranged from 0.03 ppm for fruit sprayed with the recommended rate of daminozide to 0.8 ppm for fruit with the highest daminozide residues.

Daminozide residues in cherries and peaches resulting from daminozide spray to enhance fruit maturity

Cherries sprayed with 500, 1000, 1500 and 2000 mg/l daminozide solution were analysed for daminozide residues 7, 14, 21 and 28 d after the spray. The residues decreased with time and the difference between the first and fourth week residues was significant (P&lt; 0.05) for each treatment. The residues in peaches were measured 18 weeks after the spray and were not significantly different for each treatment. There was a strong correlation (r=0.98) between the residues in cherries and the daminozide concentration in spray. The recommended concentration of darninozide spray (1000 mg/l) for cherries and peaches resulted in residues below the National Health and Medical Research Council limit of 30 mg/kg for pome fruit.

Daminozide residues in sweet cherries, and their determination by colorimetric and gas‐liquid chromatographic methods

AbstractDaminozide residues in fruit from sweet cherry trees were determined over a period of 4 years as part of an investigation into the effects of growth regulators. Analysis was by the usual colorimetric method. Additionally, for the 2 final years, a gas‐liquid chromatographic method was developed to determine the 1,1‐ dimethylhydrazine produced by hydrolysis of daminozide residues and to confirm the results from the first method.

Determination of daminozide residues on foods and its degradation to 1,1-dimethylhydrazine by cooking.

Determination of daminozide residues on foods and its degradation to 1,1-dimethylhydrazine by cooking.