A Nanodrop® (Wilmington, USA) Model ND-1000 Spectrophotometer was used. The spectrophotometer is equipped with a
xenon flash lamp and a 2048-element linear silicon CCD array detector. The optical path length is 1mm. The sample droplet is held in place by surface tension when it is slightly compressed between the drop-supporting surface (pedestal) and the sample arm. Sample pedestals are made of stainless steel and quartz fiber. The spectrum measurement is performed with two optical fibers installed in the pedestal (emitting light of a Xenon lamp) and the sample arm (spectrometer with linear CCD array). A schematic diagram of the deposition of the enriched microdrop on the pedestal
of the microvolume UV–vis spectrophotometer for measurement after HS-SDME is depicted elsewhere [5]. Absorption peak measurements were carried out at 295 nm.Headspace single-drop microextraction was performed with a commercially available 10-L syringe containing a guided-PTFE plunger (Hamilton model 1701 RN, 10 AL). Iodine generation was carried out in a 40mL amber-vial with a silicone rubber septum. A domestic microwave oven, Samsung, Model M 9245 (Seoul,South Korea), with a 2450MHzmicrowave frequency and an output power of 1000W was used for pre-treatment of aqueous samples prior to iodate determination.