Atomic absorption spectrometry A Vocabulary warm-up: hollow light source unattended ignite vapour burn cracked damaged capillary tip syringe purge burner hose bubbles align solvent replace convert ashing depth adjust graphite furnace internal Definitions – fill in the missing word: 1 If a tree trunk has no wood in it, it is ____________ 2 Keep an eye on the fire, don’t leave it _____________ 3 The part of a cooker or a stove that produces a flame is called a/an _____________ 4 A long tube made of rubber, plastic is called a/an ___________ 5 A plastic tube with a long needle is a/an ____________ 6 _____________ is the extreme part of a capillary. 7 ____________ a mass of very small drops of liquid in the air 8 ____________ is a process where a substance is converted into ashes. 9 A ball of air or gas in a liquid is called a/an _________________ 10 ___________ provides light. B Reading 1 Read the text and fill the gaps with the words from the box. ________ (1) cathode lamps are a high-intensity, stable-light source that emits the element-specific spectral lines required for atomic absorption spectrometry. A flame AAS instrument must never be left _________ (2) while the flame is burning. Install and remove the burner. If you cannot ________ (3) flame after two attempts, it is likely that there is some problem with the ________(4), ignition system, or gas supplies. Clean external and _________ (5) surfaces of the burner. Inspect the gas supply hoses regularly, and replace any that are ________ (6) or damaged. We recommend that all gas supply hoses are replaced every four years. Periodically check the external drain tube. Syringe purge A command is provided in the system software to purge the syringe to remove any ______ (7) and contamination before use. Capillary tip alignment The autosampler capillary tip must be ________ (8) with the cuvette injection hole before use, and the capillary tip depth adjustment set correctly so that the sample is injected properly onto the floor of the cuvette. The operating system of electrothermal atomisation in a graphite furnace _________ (9) of three phases: The drying phase, at 100 °C, to remove the solvent The ___________ (10) , or pyrolysis phase, at a higher temperature, to remove organic matrix The third phase atomisation, to convert the residue into an atomic vapour 2 Read the text and answer the questions: 1 What are cathode lamps and what is their role in the AAS? 2 What are the possible causes, if you cannot light the fire? 3 Do you have to change the gas supply hose more often than the drain tube? 4 When do you have to purge the syringe? Why? 5 Where do you inject the sample? How is this made? 6 How many phases are there in electrothermal atomization? What are they? C Video C1 Describing the machine. Decide where these words come to in the machine: left – middle – right? detector – burner – monochromator – hollow cathode lamp – amplifier – aspirator –pre-mixer C2 Decide if these statements are true or false. 1 According to Amy, it is important for you to know all the components of the machine. 2 Before using the AAS, you have to set up everything yourself, except for setting the wavelength. 3 You don’t have to worry about ‘knobs and stuff’ if you do only sampling. 4 Amy can’t get used to the noise made by the pump in the background. C3 Starting up the instrument. Listen and fill in the gaps. 1 Give me some ______ air, just use a regular sparkler. And that’s what your _____ looks like. You get used to the pump in the background. It’s quite warm so you want to keep the door closed once you have it _______ . 2 You’ve already had your _______ prepared. You want to start off with your zero, because you want to _______ the machine. 3 This is just your nozzle, you ______ the straw into your sample and it automatically sucks up your sample, aspirates it into the flame to create atoms. This is how we _______ your sample. 4 And then… once your ______ is being ingested by the flame, you ______ auto-zero to make sure your background is corrected for. 5 So when that’s accomplished, then it is really a matter of _______ each standard relatively quickly, since your __________ has an instance reading. 6 So just taking that in there and then you’ll see an __________ in your absorbance. 7 If you find your _________ fluctuating a lot, feel free to, at any time, take your zero and you can zero the machine at any time, just to make sure your background is relatively the same for all your ___________ readings. 8 And then you’ll __________ with the rest of your standards and now you have enough data to build the __________ curve and measure your unknown. D Grammar point 1 Irregular plural formation bacillus – locus – stimulus – genus – alga – addendum – bacterium – erratum – stratum – datum – codex – analysis – axis – basis – crisis – diagnosis – hypothesis – thesis – criterion – phenomenon – A Put into the plural: 1. Can I have both …............. of the pie, please? (half) 2. A cat is said to have no less than nine …………… (life) 3. Mary slid her ………….. into her sandals. (foot) 4. It is important to brush your ………... at least twice a day. (tooth) 5. In old-fashioned speech, ………... were often denoted as the fair sex. (woman) 6. ……….. are bacteria with a long straight shape, some of which cause diseases. (bacillus) 7. They tested the children’s reaction to simple visual …………….... (stimulus) 8. Chemical experts are doing …………... of the samples. (analysis) 9. The signs and symptoms that he showed allowed several ……………... (diagnosis) 10. Not all of the present-day cultural, natural, and social …………………. have been fully understood. (phenomenon) B Choose the correct form of the verb. 1 Gymnastics is/are my favourite sport. 2 The trousers you bought for me doesn’t/don’t fit me. 3 The police want/wants to interview the men about the accident in the lab. 4 Physics was/were my best school subject. 5 Can I borrow your scissors? Mine isn’t/aren’t sharp enough. 6 Fortunately the news wasn’t/weren’t as bad as we expected. 7 Three days isn’t/aren’t long enough for a good holiday. 8 I can’t find my binoculars. Do you know where it is/they are? 9 The United States is/are the leader in scientific research. 10 I don’t like hot weather. Thirty degrees is/are too warm for me. 2 Much, many, little, few