50%矮壮素水剂矮化一串红穴盘苗试验

为了控制一串红穴盘苗的徒长，提高穴盘苗的质量，用不同浓度的50％矮壮素水剂对其进行矮化试验，结果表明：50％矮壮素水剂800～5000倍液均能明显抑制一串红穴盘苗的株高，使其株型紧凑、茁壮，叶色浓绿。而50％矮壮素水剂800倍和1250倍两组的矮化效果相近。     

UPLC-MS/MS检测番茄酱中缩节胺、矮壮素残留的研究

利用超高效液相色谱-串联质谱(UPLC-MS/MS)技术监测缩节胺、矮壮素残留在番茄酱模拟工艺试验过程中的变化情况。监测结果显示:不同程度缩节胺、矮壮素残留在番茄酱工艺过程中不会减少,而随着番茄酱浓度的增加而同倍增加。     

食品中矮壮素和缩节胺分析方法的研究进展

近年来由于植物生长调节剂使用不当引起的食品安全问题逐渐增多,而吸引了众多研究人员对其检测方法的研究。矮壮素和缩节胺是我国农业上广泛使用的植物生长调节剂,随着人们对其残留危害的日益关注,痕量矮壮素和缩节胺的分析技术也在不断发展。文中综述了近年来食品中矮壮素和缩节胺分析前处理技术和测定方法的研究进展,并着重介绍了固相萃取法及液相色谱-质谱法,为进一步研究食品中矮壮素和缩节胺的分析检测方法以及开展风险评估提供参考。     

QuEChERS-气相色谱–串联质谱法测定粮谷和油料油脂中矮壮素残留

通过前处理及仪器条件优化，建立了QuEChERS-气相色谱-串联质谱法（QuEChERS-GC- MS/MS）法测定粮食和油料油脂中矮壮素残留的分析方法。选用小麦粉、大米、玉米、大豆、大豆油、油菜籽、菜籽油作为样品，样品经乙腈提取，无水硫酸镁和氯化钠盐析脱水、再经N-丙基乙二胺（PSA）、十八烷基键合硅胶（C18）吸附剂净化。采用衍生质谱方法考察了不同基质（小麦粉、大米、油菜籽、菜籽油）的基质效应，基质匹配外标法定量。结果表明，不同基质中矮壮素在0.05~2 μg/mL浓度范围内有较好的线性关系，相关系数R2均大于0.998 0。检出限为0.004~0.009 mg/kg，定量限为0.01~0.03 mg/kg；在3个添加水平下的平均加标回收率为73.6%~99.1%，相对标准偏差（RSD）为2.34%~7.78%（n=6）。该方法高效、灵敏度高，可满足粮谷和油料油脂样品中矮壮素残留量的检测要求。     

土壤中矮壮素、缩节胺的残留对番茄酱品质的影响

采用HPLC-MS/MS技术,同时测定土壤中的矮壮素和缩节胺残留。土壤样品经缓冲溶液提取后,经Agilent ZORBAX Rx-Si(l100mm×3.0mm,1.8μm)色谱柱分离,以含浓度10mmol/L NH4Ac+0.2%HCOOH的水溶液和甲醇(60:40,V/V)为流动相进行等度洗脱,经正离子多反应监测模式测定目标化合物。结果表明:两种化合物在1.0-50.0μg/L浓度范围内线性关系良好,定量限(LOQ)矮壮素为0.8μg/L,缩节胺为0.6μg/L;加标回收率平均在97.6%-99.5%;相对标准偏差(RSD)平均在2.5%-2.9%,适用于检测土壤中矮壮素和缩节胺。     

An intercomparison study of the determination of glyphosate, chlormequat and mepiquat residues in wheat

An intercomparison study of the determinations of glyphosate, chlormequat and mepiquat residues in cereals was performed. Four samples comprising one blank, two incurred and one spiked sample were sent to six participating laboratories. For glyphosate, two laboratories reported considerably lower results than the other four. One of the two laboratories with low results also reported low recoveries. The results of a sample spiked with 0.80 mg kg^-1 glyphosate and an incurred sample, ranged from 0.23-0.87 mg kg^-1 and 0.11-0.25 mg kg^-1 respectively. The strong correlation between the two samples (r² = 0.95) indicates a systematic between-laboratory variation. Several different principles were used for the analysis of glyphosate using different clean-up techniques and GC/MS, HPLC-fluorescence or LC/MS for detection. The results of the chlormequat residues showed more consistency. All but one laboratory obtained comparable results. However the correlation between the results for the sample spiked with 0.38 mg kg^-1 (range: 0.26-0.65 mg kg^-1) and the incurred samples (range: 0.19-0.45 and 0.15-0.23 mg kg^-1, respectively) again showed a strong correlation (r² = 0.99 and 0.88) indicating a systematic component. For mepiquat, results above the limit of quantification were only reported for the spiked sample. The results ranged from 0.29-0.92 mg kg^-1 (spiked concentration = 0.38 mg kg^-1). Three laboratories had results that deviated less than 25% from the fortified concentration. Two laboratories reported results 38% and 141% above the fortified concentration, respectively.     

The effect of the time and mode of application of gibberellic acid and inhibitors of gibberellin biosynthesis on the dormancy of potato tubers grown from true potato seed

Gibberellic acid (GA₃) and inhibitors of gibberellin biosynthesis (daminozide and chlormequat chloride) were applied to the foliage of potato plants grown from true seed (TPS) either once at two stages of plant development, 40 and 60 days after transplantation (DAT), or repeatedly at 10 day intervals starting from the same growth stages. When GA₃ was applied towards the end of the vegetative cycle (either singly 60 DAT or repeatedly from the same date), it induced rapid breakage of tuber dormancy, a reduction in specific weight, a higher rate of respiration and increased weight loss during storage. Single applications of GA₃ early in the vegetative cycle (40 DAT) had no effect on the weight loss and specific weight of tubers during storage, whereas repeated foliar applications of GA₃ starting from the same stage resulted in the formation of tubers with a low specific weight and a high rate of weight loss during storage. However, the tubers from these treatments did not break dormancy uniformly, and, although in the early stages of storage they exhibited a high rate of respiration, this declined to the level of the control (no growth regulator applied). Although daminozide and chlormequat chloride did not affect the duration of tuber dormancy and had little or no effect on any of the other metabolic indicators studied, gibberellin is nevertheless implicated in dormancy breakage, and its application late in the growth cycle may be of practical value in cases where tubers are required for planting soon after harvest. Overall, tubers from TPS respond to plant growth regulator treatment in a similar way to those from plants grown from seed tubers. Copyright © 2007 Society of Chemical Industry     

Occurrence and risks associated with chlormequat residues in a range of foodstuffs in the UK

Trends in the usage pattern of chlormequat (a plant growth regulator) on cereal crops in the UK over the past 6 years are presented. The figures have been supplemented by monitoring of chlormequat residues in food commodities through the UK surveillance programme, and for cereals, the carry-through into a number of processed cereal-based foods has been followed. A downward trend of chlormequat residue levels in pears sampled between 1997 and 2002 was observed. This decline reflects changes that were introduced in European and national regulations and which have proven to be extremely effective in reducing both the frequency of detection and levels of chlormequat residues. Both acute and chronic risk assessments were undertaken based on aggregate dietary exposure data. Even when the highest residues observed were used in the calculations, the assessments showed that both the short- and long-term intakes for all consumer groups would be unlikely to cause adverse health effects and were therefore not of any cause for concern.     

高效液相色谱-质谱法测定蔬菜中矮壮素残留

为建立蔬菜中矮壮素残留的高效液相色谱- 电喷雾离子阱质谱(LC-ESI/MS)的检测方法,样品中的矮壮素残留采用甲醇- 水- 乙酸溶液提取,离心,分取部分上清液过SCX 阳离子交换固体萃取小柱,LC-ESI/MS 法测定,以保留时间和特征离子定性、外标法定量。结果表明,矮壮素在0.03～10mg/L 范围内线性良好,线性相关系数为R2=0.9991,加标回收率为74.92%～103.28%,相对标准偏差为2.92%～10.48%,方法定量下限可达0.02mg/kg。     

矮壮素在茄子中的残留分析与膳食暴露评估

目的明确茄子中施用矮壮素的作用,分析矮壮素在茄子中的残留行为和评估其膳食暴露风险。方法开展矮壮素在茄子中的规范残留试验,茄子样品经乙酸-乙腈提取,超高效液相色谱-串联质谱法(ultra performance liquid chromatography tandem mass spectrometry,UPLC-MS/MS)检测,分析矮壮素在茄子中的残留行为,监测矮壮素对茄子生长和品质的影响,用农药残留联席会议的方法对茄子中矮壮素残留带来的膳食摄入风险进行评估。结果矮壮素在0.002~0.5 mg/L的范围内线性关系良好,在茄子中的检出限和定量限分别为0.0005和0.002 mg/kg。在0.002、0.01和0.02 mg/kg添加水平下,回收率在86.7%~102.3%,相对标准偏差为6.1%~8.2%。茄子中矮壮素残留对我国各类人群的膳食摄入暴露量为0.51~1.4μg/(kg bw·d),占ARf D的1.02%~2.8%。矮壮素应用在茄子中的推荐使用剂量为9 g ai/ha浓度喷施2次,茄子中矮壮素残留带来的膳食摄入风险极低。结论本研究为茄子中矮壮素的合理使用、科学监管及最大残留限量标准的制定提供依据。