Although the use of compounds containing heavy metals has decreased due to their toxic and environmental deterioration, traditional Chinese medicine occasionally still uses some of them as active ingredients. The inappropriate intake of these medicines sometimes causes death. In rural areas of China, many a few quack doctors often treat diseases, e. g., psoriasis, with applying a kind of poultice which usually contains several kinds of heavy metals.

Such a case happened in a rural area of northeast China three years before a boy likely died from the application of poultice onto his large part of skin ^[12]. In order to find his death reason, the boy’ s soft tissues, including heart, liver, kidney, subcutaneous tissue and heart-blood, were digested in a mixture of 6 ml of nitric acid (HNO3) and 2 ml of hydrogen peroxide (H2O2). All the samples were decomposed at the maximum temperature of 200º C in sealed TFM tubes. ICP-MS measurements revealed that the contents of arsenic (As), hydrargyrum (the more acceptable version of this element as “ mercury” ) (Hg) and lead (Pb) were hundreds even thousands times higher in the samples than the normal content in the controlled tissue samples, indicating the fact of poisoning. It is rare that these three heavy metals coexist in one formula of Chinese medicine because of the potential to cause poisoning. According to the contents of the elements in different tissues of the dead boy, these heavy metals were deduced to coordinate in the body and redistribute in different tissues. Arsenic was deposited mainly in liver and kidney while mercury mostly sank in kidney. Lead was metabolized slowly, presenting basically itself in skin and subcutaneous tissues.

There are many Chinese famous brands of liquors which are expensive. For to profit, some people are increasingly manufacturing and selling the fake and/or quality-inferior liquors on market. Usually, the GC/MS is employed to analyze the alcohols and ketones. Yet, ICP-MS measurement is a better alternative to fulfill this task for identification of trace elements in the liquors whose reality needs to be verified. Although the microwave digestion is usually used to treat the samples with nitric acid, it is inadequate for the liquor to receive the very same treatment because of the high content of alcohol. In our laboratory, 21 different brands of liquors suspected of faked ones were volatilized and then added 2ml of nitric acid (ultra-pure) to dissolve the samples and transferred to 25 ml volumetric flask with deionized water for ICP-MS measurement ^[13], leading to be measured of elements of lithium (Li), potassium (K), vanadium (V), copper (Cu), arsenic (As), strontium (Sr) and lead (Pb). The concentration of element potassium (K) is generally higher than other elements. Copper (Cu) is relatively lower in concentration but changes dramatically among different liquor samples. Arsenic (As) is higher with its concentration of 32 ng/ml in one kind of liquor than the other samples where their As concentrations are low and no obvious difference amid them. Lithium (Li) and vanadium (V) are relatively low of content in the samples, varying little in different ones of them. Lead (Pb), a heavy metal element harmful to human health, is very low of content in the samples. With determination and measurement of all the elements plus their concentrations by ICP-MS, different brands of liquor samples have been differentiated thoroughly and totally.

Cars are becoming even more involved in different kinds of cases, mainly the traffic accidents in China. Headlights of cars are easily broken and left over at the scenes. Plastic, instead of glass, is commonly used into automobiles’ headlights now. In many cases, plastic headlight shucks are necessarily compared to determine whether they come from the same source. In forensic science, plastic is typically identified by the way of infrared spectroscopy to define its type and/or by X ray dispersive spectrometry (EDX) to conduct elemental analysis for deciding if there are any additive elements. But for the plastic of car headlight shuck, its types of fabricating material are almost same, resulting in the impossibility to differentiate them by the infrared spectroscopy and/or EDX. Since trace amounts of additives can improve the physical and chemical properties of the headlight shuck during the manufacture process, ICP-MS, able to differentiate the elemental ingredients, is used to find out the additives and their amount present in the plastic samples. Such information can help make the comparison to disclose their provenance. In one experiment conducted in our lab, 33 different plastic samples of headlight shuck were collected and analyzed by ICP-MS. With the parameter optimization for microwave digestion, the contents of boron (B), sodium (Na), magnesium (Mg), calcium (Ca), potassium (K), titanium (Ti), scandium (Sc), chromium (Cr), lead (Pb), manganese (Mn), strontium (Sr), ferrum (iron) (Fe), hydrargyrum (mercury) (Hg) were measured along with their Euclidean distances. Taken together of the 528 pairs of comparison between different samples, the differentiating rate is about 92.8 %, demonstrating that ICP-MS, when combined with the Euclidean data processing, is reliable to compare the plastic samples of headlight shuck.

Chinese government rules that the releasing of fluids or gases into the environment must be strictly controlled. Yet, there are lots of illegal factories, who are engaged in, e. g., electroplating and have no post-disposing devices, often directly discharging the waste water into soils. The waste water and polluted soil samples are often brought to our lab to test if the concentrations of some heavy metals are higher than the blank sample. Once, the elements of zinc (Zn), chromium (Cr) and lead (Pb) were examined in more than ten cases. Waste water was usually diluted and subjected to direct analysis by ICP-MS. For the soil samples controlled with its blank specimen, they were commonly digested with the mixture of nitric acid (HNO3), hydrochloric acid (HCl) and hydrofluoric acid (HF) at the volume ratio of 6:5:1.5 under 210º C for 20 minutes. The elements of zinc (Zn) and chromium (Cr) were measured with the cell collision, together with the lead (Pb) being determined with the standard mode by ICP-MS.

Trace elements in soil sample are usually measured by solution-based ICP-MS. Nevertheless, LA-ICP-MS method is preferred when the sample’ s amount is less than 0.1 g. In one of our experiments, the soil samples were sieved and pressed for measurement ^[16]. In order to better ablate the soil samples with laser, the parameters including the laser spot size, energy level, pulse and the frequency, were to be optimized. It was found that two Chinese standard soil samples got good results by the raster mode setting with the laser spot of 150 μ m and energy level at 100 %. The data analyzed were close to those labeled. The soil samples, unable to be differentiated by XRF that is eligible for major elemental composition, were further discriminated by LA-ICP-MS choice.

Metal wires are often found to truss dead bodies and/or other objects in crime scenes. These wires are usually thin and their main components generally tend to be same, thereby making the inter-sample comparison difficult and even impossible. LA-ICP-MS provides a perfect way to solve this kind of problems. In a case where the metal wires taken from the corpse and the suspect were required to be compared, both wires are of iron and their diameter is only about 1.2mm ^[17]. In our experiment, the cross sections were fresh created to undergo the LA-ICP-MS analysis. With presence of the elements nickel (Ni), cobalt (Co) and copper (Cu) plus their different concentrations measured in the evidence, these two ferreous wires were eventually differentiated. Necessary to mention, absolute counts per second of each element were often suggested to record and compare directly because of the frequent unavailability towards the standards of similar matrix to the evidence.

The counterfeit currency is one of the most serious problems in the world, having been bothering authorities of many countries since the appearance of currency. China is not immune from these problems and has suffered from them for over years. The most widely used and effective way to examine counterfeit banknotes is by visual and physical comparison. However, for the stuff that makes counterfeit notes, such as the paper, printing ink or toner together with those semi-finished samples that have had yet none of characteristic additional imitations of security features, better strategies should be used to acquire enough information to identify if they come from the same source by which to make cases linked. LA-ICP-MS is one of the best ways to examine paper samples, capable of meeting the fast analysis and nondestructive to the trace paper or paper with ink on it. In our lab, LA-ICP-MS was ever utilized to analyze 21 special paper samples that were seized from 12 different cases involving with counterfeit banknotes in different provinces^[18]. The data were processed by multivariate calculation of cluster and principle-component analyses. All these paper samples were mainly classified into three groups from which eight separate cases were successfully linked together. The results were confirmed by the suspects who bought this kind of paper and used them to make counterfeit notes.