食品用金属製器具の材質中鉛試験法  [in Japanese] Test Method for Lead in Metal Utensils for Food Contact Use  [in Japanese]

金属製品の材質中鉛試験法を確立した．測定法としてフレーム-原子吸光分析(AAS)法，フレームレス-原子吸光分析(GFAA)法，誘導結合プラズマ発光分析(ICP)法および蛍光X線分析(XRF)法の比較を行い，試験溶液の調製法についても検討を行った．試料 100 mg を精秤し，塩酸・硝酸(3 : 1)混酸(チタンは塩酸)を 2.5 mL 加えて溶解した．これに水を加えて 50 mL としたものを試験原液とし，0.1 mol/L 硝酸で適宜希釈して試験溶液とした．鉛を0.1％ 添加したときの回収率は90～118％ と良好であった．鉛を0.0098～0.11％ 含有する標準物質を測定したところ，各定量値は認証値とほぼ近い値を示した．本法はアルミニウム，鉄，ステンレス鋼，銅，スズ，チタン製品に適用でき，AAS法，GFAA法，ICP法ともに鉛試験法として適用可能であった．また，XRF法はスクリーニング法または簡易定量法として有用であった．ICP法を用いて市販金属製器具22検体の鉛含有量を測定したところ，6検体から0.011～0.040％ の鉛が検出された．

We compared test methods for measurement of lead in metal utensils using flame-atomic absorption spectroscopy (AAS), graphite furnace-AAS (GFAA), inductively coupled plasma atomic emission spectrometry (ICP) and X-ray fluorescence analysis (XRF). The procedure for preparation of the test solution was improved. A 100 mg of sample was dissolved in 2.5 mL of HCl and HNO3 (3 : 1) mixture (in the case of titanium sample, dissolved in HCl). Stock solution was prepared by diluting to 50 mL with water. The test solution was prepared by diluting with 0.1 mol/L HNO3. The recoveries of lead added to various kinds of metal reagent at the level of 0.1% were 90-118%. When standard materials which contained lead at the level of 0.0098-0.11% were measured, the measured values were in close agreement with the standard values. These procedures are applicable to aluminum, iron, stainless steel, copper, tin and titanium products. The AAS method, GFAA method and ICP method were suitable as the lead test methods. Moreover, the XRF method was useful as a screening method or a simple determination method. The ICP method was used to determine the lead contents in 22 kinds of commercial metal utensils, and 0.011-0.040% of lead were detected in 6 samples.