使用X射線(xiàn)能量色散熒光光譜儀(XRF Analyzer)的測(cè)試程序和步驟
1 光譜儀準(zhǔn)備
a) 按照儀器的工作說(shuō)明書(shū)給儀器通電,加熱設(shè)備,按廠家說(shuō)明書(shū)對(duì)儀器進(jìn)行穩(wěn)定。
b) 確保測(cè)試穩(wěn)定,并按照制造商的說(shuō)明使檢測(cè)器穩(wěn)定
2 校準(zhǔn)
a) 根據(jù)儀器用戶(hù)手冊(cè)的說(shuō)明,按照第 7 節(jié)的說(shuō)明選擇參考樣品作為校準(zhǔn)樣品。樣品中的元素
濃度應(yīng)該不一樣。如果校準(zhǔn)覆蓋的元素多,濃度范圍大,則需要大量的校準(zhǔn)樣品。
由于以下原因,校準(zhǔn)樣品的數(shù)量有所減少:
— 用基本參數(shù)法校準(zhǔn)(元素小于標(biāo)準(zhǔn))
— 使用基本參數(shù)方法校準(zhǔn)(使用具有相似元素的標(biāo)準(zhǔn))
— 使用基本參數(shù)方法分析加經(jīng)驗(yàn)校準(zhǔn)
b) 分析方法校準(zhǔn)考慮了光譜的干擾、基體效應(yīng)等影響,這些都會(huì)影響光譜中熒光散射的強(qiáng)度
決心的程度。這些效果的列表可以在本章的附件中找到。
c) 為保證各測(cè)量元素的分析性能合格,需選擇合適的激發(fā)參數(shù),使儀器處于好的狀態(tài)
測(cè)量條件。這些條件是儀器需要的。通常,此信息可以在分析師的說(shuō)明手冊(cè)中找到
d) 作為一般準(zhǔn)則,推薦方法的用戶(hù)知道,相互元素譜的干擾和樣品間基質(zhì)的變化將充分影響
對(duì)每個(gè)分析物結(jié)果的準(zhǔn)確度、精密度和檢測(cè)限。例如純聚乙烯中Cd的檢出限可達(dá)
至 15mg/Kg,但當(dāng)存在 10% 溴化合物和/或 2% 銻時(shí),無(wú)法達(dá)到檢測(cè)限
3 檢測(cè)器性能檢查
無(wú)論設(shè)備是否滿(mǎn)足要求的性能標(biāo)準(zhǔn),都需要通過(guò)測(cè)量認(rèn)證參考材料或相關(guān)參考樣品
決定。樣品中所含元素的濃度不得大于測(cè)試元素篩選限值的3-5倍(見(jiàn)表3)。按參考樣本
產(chǎn)品得到的結(jié)果必須在樣品測(cè)試誤差的允許范圍內(nèi)。當(dāng)設(shè)備用于分析未知材料時(shí),制造商應(yīng)提供
標(biāo)準(zhǔn)操作程序 (SOP) 和適當(dāng)?shù)膮⒖紭颖?。推薦的方法應(yīng)該保證操作者可以獲得高質(zhì)量的定量分析結(jié)果。
4 測(cè)試樣品的放置
a) 如果待測(cè)樣品可以放置在臺(tái)式X射線(xiàn)熒光光譜儀內(nèi)部的樣品室中,并且待測(cè)樣品被正確測(cè)量
位置,可以進(jìn)行相應(yīng)的測(cè)試。如果待測(cè)樣品不適合放置在樣品室中,則必須將其切割以適合
尺寸易于測(cè)量。為了使測(cè)試結(jié)果有效,必須滿(mǎn)足儀器關(guān)于樣品厚度和質(zhì)量的要求。
因?yàn)榉浅P〉幕虮〉臉悠房赡懿环线@個(gè)條件。在這種情況下,這樣的小樣本(如蝸牛)
線(xiàn)釘)放置在樣品杯中,然后進(jìn)行分析。同樣,相似的薄樣品應(yīng)堆疊在一起,以便
足以達(dá)到有效分析的最小樣品厚度限制。一個(gè)總的原則是所有樣本必須*
蓋住光譜儀的測(cè)量窗口。對(duì)于聚合物和輕合金,例如 Al、Mg 和 Ti,其厚度至少應(yīng)為 5mm。
液體的最小厚度為 15 毫米,而其他合金的厚度約為 1 毫米。但由于設(shè)備的個(gè)體差異,
所需的樣本量也不同。光譜儀的操作人員應(yīng)參考設(shè)備手冊(cè)或遵循制造商的要求。
制備樣品的尺寸/質(zhì)量/厚度。
b) 如果在便攜式 XRF 光譜儀上進(jìn)行測(cè)試,必須注意光譜儀的測(cè)量窗口應(yīng)為
測(cè)試樣品相對(duì)并直接接觸。小樣品或非常薄的樣品應(yīng)按照上述 a) 中提到的方法進(jìn)行操作。當(dāng)然
然后使用附件(如果有)進(jìn)行分析,讓操作員可以測(cè)量樣品杯中的樣品。關(guān)于最
小樣品的尺寸/質(zhì)量/厚度規(guī)定也適用于便攜式分析。
c) 如果樣品是液體、粉末或球形,或者只是一個(gè)小樣品,則需要
在樣品杯中測(cè)量薄膜。處理此窗膜時(shí),請(qǐng)注意不要
觸摸其表面以避免弄臟它
5 篩選測(cè)試
a) 按規(guī)定時(shí)間進(jìn)行測(cè)試。
b) 顯示和記錄分析結(jié)果。
6 結(jié)果分析
各種類(lèi)型的 XRF 光度計(jì)單獨(dú)使用,分析方法允許用戶(hù)將樣品分為以下三類(lèi)之一:
a)“合格"——如果所有元素的定量分析結(jié)果均小于表2所列的下限,則該樣品為合格。
b) “不合格"——如果全部高于表 2 所列的上限,則樣品檢測(cè)為不合格。
c) “未定"——如果 Hg、Pb 或 Cd 任何元素的定量分析結(jié)果在中間區(qū)域
或元素Br和Cr的結(jié)果高于表2所列的上限,分析結(jié)果未定。 也得進(jìn)步一步研究。 本次測(cè)試“未定"
The test procedure and steps of using X-ray energy dispersive fluorescence spectrometer (XRF Analyzer)
1 Spectrometer preparation
a) Power on the instrument according to the working instructions of the instrument, heat the equipment, and stabilize the instrument according to the manufacturer's instructions.
b) Ensure that the test is stable, and make the detector stable according to the manufacturer's instructions
2 calibration
a) According to the instructions in the instrument user manual, follow the description in section 7 to select the reference sample as the calibration sample. Of the elements in the sample
The concentration must be different. If the calibration covers a lot of elements and the concentration range is large, a lot of calibration samples are needed.
The number of calibration samples has decreased due to the following reasons:
— Calibrate with the basic parameter method (the elements are less than the standard)
— Calibrate with the basic parameter method (using a standard with similar elements)
— Use basic parameter method analysis plus experience to calibrate
b) The analysis method calibration takes into account the interference of the spectrum, matrix effects and other effects, which will affect the intensity of fluorescence scattering in the spectrum
Degree of determination. A list of these effects can be found in the attachment to this chapter.
c) In order to ensure the qualified analytical performance of each measurement element, it is necessary to select the appropriate excitation parameters to make the instrument at the best
Measurement conditions. These conditions are unique to the instrument. Typically, this information can be found in the analyst’s instruction manual
d) As a general guideline, users of the recommended method know that the interference of mutual element spectra and changes in the matrix between samples will fully affect
To the accuracy, precision and minimum detection limit of each analyte result. For example, the detection limit of Cd in pure polyethylene can reach
To 15mg/Kg, but when 10% bromine compound and/or 2% antimony are present, the detection limit cannot be reached
3 Detector performance check
Regardless of whether the equipment meets the required performance standards, it needs to pass measurement certification reference materials or related reference samples to
determine. The concentration of the element contained in the sample must not be greater than 3-5 times the screening limit of the test element (see Table 3). By reference sample
The result obtained by the product must be within the allowable range of the sample test error. When the equipment is used to analyze unknown materials, the manufacturer should provide
A standard operating procedure (SOP) and an appropriate reference sample. The recommended method should ensure that the operator can get high quality
Quantitative analysis results.
4 Placement of test samples
a) If the sample to be tested can be placed in the sample chamber inside the desktop X-ray fluorescence spectrometer, and the sample to be tested is properly measured
Location, you can perform the corresponding test. If the sample to be tested is not suitable for being placed in the sample chamber, it must be cut to fit
The size is easy to measure. In order for the test results to be valid, the minimum requirements of the instrument regarding sample thickness and quality must be met.
Because very small or thin samples may not meet this condition. In this case, such small samples (such as snails)
Wire nails) are placed in a sample cup, and then analyzed. Similarly, similar thin samples should be stacked together so that
Enough to reach the minimum sample thickness limit for effective analysis. A general principle is that all samples must be completely
Cover the measurement window of the spectrometer. For polymers and light alloys such as Al, Mg and Ti, it should be at least 5mm thick.
The minimum thickness for liquids is 15mm, while for other alloys the thickness is about 1mm. However, due to individual differences in equipment,
The required sample size is also different. The operator of the spectrometer should refer to the equipment manual or follow the minimum required by the manufacturer.
Size/mass/thickness to prepare samples.
b) If the test is performed on a portable XRF spectrometer, it must be noted that the measurement window of the spectrometer should be
The test sample is opposite and in direct contact. Small or very thin samples should be operated in accordance with the method mentioned in a) above. Of course
Then use an accessory (if available) for analysis, allowing the operator to measure the sample in the sample cup. About the most
The size/quality/thickness regulations for small samples also apply to portable analysis.
c) If the sample is liquid, powder or spherical, or just a small sample, it needs to be
The film is measured in the sample cup. When handling this window film, be careful not to touch its surface to avoid staining it
5 screening test
a) Test according to the stipulated time.
b) Display and record analysis results.
6 Result analysis
Various types of XRF photometers are used individually, and the analysis method allows users to classify samples into one of the following three categories:
a) "Pass"-if the results of quantitative analysis of all elements are all less than the lower limit listed in Table 2, the sample has been tested Is qualified.
b) "Unqualified"-If all of them are higher than the high limit listed in Table 2, the sample will be unqualified after testing.
c) "Undecided"-if the result of quantitative analysis of any element of Hg, Pb or Cd is in the middle area
Or the results of the elements Br and Cr are higher than the upper limit listed in Table 2, and the analysis result is undecided. Also have to make progress
One-step research. This test is "undecided"
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