AOAC 984.27-1986
用感应耦合等离子体发射光谱法测定婴儿食品中钙、铜、铁、镁、锰、磷、钾、钠和锌

Calcium, Copper, Iron, Magnesium, Manganese, Phosphorus, Potassium, Sodium, and Zinc in Infant Formula Inductively Coupled Plasma Emission Spectroscopic Method

标准号

AOAC 984.27-1986

发布日期

1986年01月01日

实施日期

1986年01月01日

废止日期

无

中国标准分类号

X04

发布单位

US-AOAC

引用标准

JAOAC 67

适用范围

This standard is specifies Calcium, Copper, Iron, Magnesium, Manganese, Phosphorus, Potassium, Sodium, and Zinc in Infant Formula Inductively Coupled Plasma Emission Spectroscopic Method A. Principle Test portion is digested in HNO3/HCiO4 and elements are determined by ICP emission spectroscopy.B. Reagents (a) Water.--Distilled, deionized. Use throughout. (b) Perchloric acid.--Double-distilled. Dilute l 0 mL to 50 mL with H20. (c) Standards.--All preparations yield 1000/-tg/mL. (1) Calcium.--Place 2.4973 g CaCO3 in I L volumetric flask with 300 mL H20, add 10 mL HCI, and after CO2 has been released, dilute to I L. (2) Copper.--Dissolve 1.000 g Cu in 10 mL HCI plus 5 mL H20 to which HNO3 is added dropwise until dissolution is complete. Boil to expel fumes, cool, and dilute to 1 L with H20. (3) Iron.--Dissolve 1.000 g Fe wire in 20 mL 5M HCI; dilute to 1L with H20. (4) Potassium.--Dissolve 1.9067 g KCI in H,O and dilute to 1 L with H20. (5) Magnesium.--Dissolve 1.000 g Mg in 50 mL 1M HCI and dilute to 1L with H20. (6) Manganese.--Dissolve 1.000 g Mn in 10 mL HCI plus 1 mL HNO3 and dilute to 1 L with H20. (7) Sodium.--Dissolve 2.5421 g NaCI in H20 and dilute to 1L with H20' (8) Phosphorus.--Dissolve 4.263 g (NH4)2HPO4 in H,O and dilute to 1 L with H20. (9) Zinc.--Dissolve 1.000 g Zn in 10 mL HCI and dilute to 1 Lwith H20. Commercially available certified standards may be substituted for any of the above element solutions. (d) Calibration standards.--Prepare to concentration indicated in Table 984.27, using standards above. All calibration standardsshould be prepared to contain 20% HCIOto approximate HCIOconcentration in diluted digest.C. Apparatus (a) ICP emission spectrometer.--Model 975 Plasma Atom Comp (Jarrell-Ash Corp., 27 Forge Pkwy, PO Box 9101, Franklin, MA 02038-9101, USA), or equivalent, capable of simultaneous or sequential determination of Ca, Cu, Fe, K, Mg, Mn, Na, P, and Zn.Minipuls 2 peristaltic pump (Gilson Medical Electronics, PO Box 27, 3000 W. Beltline Highway, Middleton, WI 53562, USA), or equivalent, used to feed glass crossflow nebulizer. Suggested operating parameters: warm-up time (plasma on), 30 rain; exposure time, 5 s; integration cycles, 1 cycle (2 on line exposures, 1 offline exposure); forward power, 1.1 KW; reflected power, <5 watts; analyte uptake rate (w/pump), 0.8 mL/min; observation height: 16 mm above load coil (optimized for Mn). (b) Controllable heating mantle and acid scrubber.--Labconco 60301 (Labconco, 8811 Prospect, Kansas City, MO 64132, USA), or equivalent. (c) Glassware.--Soak overnight in 10% HNO3 and thoroughly rinse with H20.