Precautions for starting atomic absorption spectrophotometer
1. Space and venue requirements:
The installation room for atomic absorption spectrometer should have a minimum area of 12m2, with no direct sunlight on the instrument. The room should have water supply and drainage, no heat sources other than water, heating, and air conditioning, and no dust. The walls and ceilings must be painted to prevent dust and debris caused by general coatings. There should be no large electrical equipment or strong vibrating machinery around the instrument room.
2. Circuit requirements:
The cable entering the instrument room should be a two-phase AC power with a ground wire. The graphite furnace and air compressor are independently powered by an air circuit breaker. (Specific circuit diagrams can be consulted)
The use of high current instantaneous power supply in graphite furnaces can cause significant voltage fluctuations. The starting current of air compressors is relatively high, so sharing a live wire can seriously affect the stability of the host. Although the instrument allows a deviation of+10% from the 220V power supply, this refers to the wide voltage working range of the instrument, not+10% fluctuations. If the 220V voltage supplied to the host fluctuates between 5V, a 3KW voltage regulator should be added to ensure that the instrument is in a relatively stable working state. According to national standards, all three hole flat sockets with ground wire connectors should be used. Three hole sockets can be installed on one side of the air compressor, and it is recommended to install a 30A air switch (without grounding wire) on the other side of the graphite furnace. All these sockets are arranged on a distribution panel and installed on the wall behind the instrument panel. The instrument must have a qualified grounding wire, and water pipes or heating pipes must not be used as a substitute for grounding. Qualified grounding wires should be connected (drawings can be consulted). Air conditioning should be installed: the temperature should not exceed 35 ℃ in summer and not be lower than 15 ℃ in winter. The temperature change rate is less than 1 ℃/h, and the relative humidity is ≤ 85%.
3. Requirements for the instrument bench:
The instrument measures 880mm in length, 540mm in width, and 480mm in height (specifically designed for our household instruments, with a miniaturized module that saves space);
The size of the instrument table is a cement table or wooden table with a length of 230cm and a width of 90cm;
The tabletop should be able to bear a weight of 170kg. If it is a wooden table, the thickness of the tabletop should not be less than 5cm;
The instrument table should not be placed close to the wall and should have a spacing of at least 50cm (specific drawings can be consulted).
4. Water source requirements:
There should be a water basin near the instrument room, with a height of less than 90cm, to facilitate the discharge of cooling water from the instrument. The inlet should be equipped with a water hose that can connect to a Φ 8 × 1.5 hose, and the outer diameter of the joint should be 9-10mm. The water pressure should ensure a flow rate of 3 liters per minute. The water temperature cannot be higher than 22 ℃, but it cannot be lower than 15 ℃ either. (It is recommended to choose cooling water circulation to reduce the amount of visible water in the instrument room, which is beneficial for the preservation of the instrument)
5. Exhaust requirements:
An exhaust device should be installed above the instrument as shown in the upper right image to promptly remove harmful gases generated during analysis.
6. Requirements for various gases
Various gases (argon or nitrogen, acetylene gas<99.9% or above, laughing gas, etc.) should be placed outside the instrument room, equipped with their own pressure gauges, and introduced into the room for analysis using stainless steel pipes (Φ 5) or Φ 8 × 1.5 hoses.
Low noise air compressors can be placed outdoors or near instruments.
The dissolved acetylene in steel cylinders should comply with the safety requirements of GB6819-1996, and high-purity acetylene with a purity greater than 99.9% should be used. The acetylene cylinder should be placed upright. High purity argon gas (purity of 99.99% or above) or high-purity nitrogen gas (purity of 99.999%).
7. Requirements for various solutions:
Should have Cu standard reserve solution and Cd standard reserve solution;
Should have deionized water (at least 10 liters);
At least one bottle of high-grade pure nitric acid and one bottle of high-grade pure hydrochloric acid;
Various types of pipettes (1ml, 2ml, 5ml, 10ml, each no less than five), volumetric flasks (100ml/12), measuring cylinders (500ml/1), beakers (500ml/3); 1 ear ball and 2 glass rods;
8. If you choose a hydride generator (190mm in length, 215mm in width, and 220mm in height), you must also have:
Borohydride Na or Borohydride Jia, analytical purity;
High purity nitrogen gas (above 99.999%) and pressure reducing valve;
Arsenic (As+3) standard solution;
Potassium iodide (KI) solid (analytical grade is sufficient);
Solid ascorbic acid (analytical grade is sufficient);
1 bottle of high-quality pure hydrochloric acid;